landfill leachate treatment using free water
TRANSCRIPT
LANDFILL LEACHATE TREATMENT USING FREE WATER SURFACE
CONSTRUCTED WETLANDS
SITI RABE’AH BINTI OTHMAN
A project report submitted in partial fulfillment of the requirements for the award of the degree of
Master of Engineering (Civil – Environmental Management)
Faculty of Civil Engineering
Universiti Teknologi Malaysia
NOVEMBER, 2007
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This work is dedicated to my parents Hj. Othman Hj. Kassim,
Hjh. Laila Mariam Hj. Pudzil and my family members who love
me and support me during my whole journey of education.
Without you all who am I today!
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ACKNOWLEDGEMENT
“In the name of God, the most gracious, the most compassionate”
I would like to thank and express my appreciation for the support that I received throughout my studies from my supervisor, Assoc. Prof. Dr. Johan Sohaili and Pn. Normala Hashim and Cik Shamila Azman. They went above and beyond the call of my duty as members of my steering committee, and never failed to keep my eyes on the bottom line.
I enjoyed doing my M.Eng study under their supervision. Also, during my stay at Universiti Teknologi Malaysia I have had the chance to meet and learn from many people. Among them there are three individuals that have been a great teacher and friend, and have contributed to my studies by discussing and commenting on different aspects of this work. Special thanks go to Dr. Fadhil Othman, Dr. Fadhil Md. Din, and Dr. Azmi Aris as well.
Many friends and colleagues have contributed to my studies in many ways. The exceptional help, support and friendship that I received from Mohd. Izuddin, Mohd. Fahmi, Hafizi, Abd. Karim and Azhan.
Finally, I wish to express my heartfelt thanks to all my environmental
laboratories technicians, especially to Pak Usop, En. Ramlee Ismail, Pn. Rosmawati and En. Muzaffar for their timely support during my stay in the laboratories.
“May Allah bless us with His Taufik and Hidayat. May we benefit from the knowledge He has given us. May we always be under His Protection and Guidance. May He forgive us for our sins, those we know and those we do not know. May He place us on the righteous path and steadfast our Imans. May He shower our one and true Prohphet Muhammad Alaihisalam and his family and followers, with eternal blessings. Amin amin, ya rabbal-alamin”
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ABSTRAK
Masa kini, pengurusan sisa pepejal dan rawatan airsisa merupakan masalah utama yang sedang kita hadapi. Jumlah sisa pepejal yang dihasilkan di seluruh dunia meningkat secara mendadak, begitu juga di Malaysia amnya. Walaupun terdapat pelbagai alternatif untuk mengurangkannya, atau untuk tujuan rawatan dan pelupusan. Tempat pelupusan sampah (landfill) masih kerap dipraktikkan di negara maju dan membangun. Walaubagaimanapun, kaedah landfill ini menyebabkan penghasilan air leleh (leachate). Air leleh (leachate) dari pusat pelupusan sampah adalah merupakan cecair yang menyusup dari sesuatu tapak pelupusan ke alam sekitar. Tanah bencah buatan (constructed wetlands) muncul sebagai salah satu kaedah rawatan alternatif yang berpotensi dengan menggunakan tumbuhan tenggelam (emergent plant) untuk menyingkirkan bahan cemar dari air leleh. Dalam kajian ini, tanah bencah buatan telah di bangunkan menggunakan tumbuhan Limnocharis flava untuk merawat air leleh dari tapak pelupusan. Kepekatan air leleh yang berbeza (50% dan 33%) telah dikaji di tanah bencah buatan tersebut untuk membandingkan keupayaan rawatan dari segi keupayaan penyingkiran bahan cemar dan keupayaan penyingkiran tanah bencah buatan apabila masa tahanan hidraulik (HRT) yang berlainan digunakan. Keputusan menunjukkan bahawa keupayaan penyingkiran tertinggi bagi HRT 3 hari telah diperolehi di Cell B dimana peratus penyingkiran NH3-N, PO4
3-, Mn, Fe, Turbidity, dan TSS adalah 83%, 88%, 91%, 92%, 100%, dan 98%. Bagi HRT 6 hari pula, penyingkiran tertinggi adalah NO3-N, PO4
3-, Turbidity dan TSS dimana peratusan adalah 98%, 98%, 100% dan 90% telah didapati di Cell B, selain itu, penyingkiran tertinggi bagi Cell A pula berlaku di HRT 6 hari dimana parameter yang diperolehi adalah NH3-N, COD, Mn, Fe, Tubidity dan TSS iaitu 93%, 91%, 90%, 94%, 100% dan 90%. Walaubagaimanapun, keputusan makmal menunjukkan bahawa keupayaan penyingkiran bagi HRT 3 hari dan 6 hari tidak menunjukkan perbezaan yang ketara.
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ABSTRACT
Nowadays, solid waste management and wastewater treatment are the most important problems that we are facing. The amount of solid waste produced around the world is increasing at high rate as well as in Malaysia. Although there are different alternatives to reduce them or for their treatment and disposition, landfill is still the most common practice in developed and developing countries. However, the landfill method causes generation of leachate Landfill leachate refers to the liquid that seeps through a landfill site and enters the environment. Constructed wetlands emerged as one of the potential treatment alternative that employed emergent plants to remove pollutant from leachate. In this research, a constructed wetland was developed by using Limnocharis flava to treat the landfill leachate. Different leachate concentration (50% and 33%) was studied in the constructed wetland to compare the treatment efficiency in terms of pollutants removal in leachate and the efficiency of the system in different hydraulic retention time (HRT). The result shows a better removal efficiencies at HRT 3 days can be obtained in Cell B where the parameter are NH3-N, PO4
3-, Mn, Fe, Turbidity, and TSS (83%, 88%, 91%, 92%, 100%, and 98% removal). The highest removal at HRT 6 days are NO3-N, PO4
3-, Turbidity and TSS (98%, 98%, 100% and 90%) can be obtained in Cell B, while in Cell A the highest removal parameters are NH3-N, COD, Mn, Fe, Tubidity and TSS (93%, 91%, 90%, 94%, 100% and 90%). However, the highest removal of COD can be obtained at HRT 6 days in control unit of 94%. However, the laboratory result shows that the removal efficiencies for HRT 3 days and HRT 9 days have not much different.
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TABLE OF CONTENT
CHAPTER TITLE PAGE
DECLARATION
DEDICATION
ACKNOWLEDGEMENT
ABSTRAK
ABSTRACT
TABLE OF CONTENTS
LIST OF FIGURES
LIST OF PLATES
LIST OF TABLES
LIST OF SYMBOLS
LIST OF APPENDICES
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iii
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x
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xiv
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1 INTRODUCTION
1.1 Reviews
1.2 Constructed Wetland and Landfill
1.3 Objectives of the Study
1.4 Scope of Study
1.5 Problem Statement
1
1
2
4
5
5
2 LITERATURE REVIEW
2.1 Introduction
2.2 What is Constructed Wetlands?
2.3 Types of Constructed Wetland
2.3.1 Free Water Surface Wetlands (FWS)
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7
8
9
10
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2.3.2 Sub-Surface Flow Wetlands (SSF)
2.3.3 Hybrid Systems
2.4 Theory of Operation
2.5 Aquatic Macrophytes
2.6 Treatment Process Mechanisme
2.6.1 Biodegradable Organic Matter Removal
2.6.2 Metal Removal Mechanisms
2.6.3 Removal of Nitrogen
2.6.4 Removal of Phosphorus
2.6.5 Solids Removal
2.7 Landfill Leachate
2.7.1 Leachate Generation
2.7.2 Leachate Composition
2.8 Leachate Contol Strategies
2.9 Type of Landfill
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17
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29
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3 RESEARCH METHODOLOGY
3.1 Introduction
3.2 Experimental Set Up and Operating Conditions of
Constructed Wetland
3.3 Experimental Analysis
3.3.1 Analysis of Leachate
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39
41
44
44
4 RESULTS AND DISCUSSION
4.1 Introduction
4.2 Pollutant Removal In Leachate
4.3 Water Quality Analysis
4.3.1 Total Suspended Solid Removal
4.3.2 Turbidity Removal
4.4 Organic Matter Analysis
4.4.1 Biochemical Oxygen Demand Removal
4.5 Chemical Water Quality Analysis
4.5.1 Ammonia Nitrogen Removal
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4.5.2 Nitrate Nitrogen Removal
4.5.3 Phosphorus Removal
4.5.4 Manganese Removal
4.5.5 Iron Removal
4.6 Analysis of Variance
4.7 Conclusion
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5 CONCLUSIONS
5.1 Introduction
5.2 Recommendations
5.3 Conclusions
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71
REFERENCES 73
APPENDICES 84
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LIST OF FIGURES
NO. TITLE PAGE
Figure 2.1 Typical surface flow and subsurface flow constructed wetlands 9
Figure 2.2 Classification of constructed wetlands for wastewater treatment
(Vymazal, 2001)
10
Figure 2.3 Free water surface flow (FWS) constructed wetland 12
Figure 2.4 The free water surface constructed wetlands in a foreign
country
12
Figure 2.5 The subsurface constructed wetlands in a foreign country 13
Figure 2.6 Longitudinal constructed wetlands with horizontal SSF. Key:
1) Inflow of mechanically pretreated wastewater; 2)
Distribution zone filled with large stone; 3) Impermeable liner;
4) Medium (Gravel, sand, crush stones); 5) Vegetation; 6)
Outlet collector; 7) Collection zones filled with large stones; 8)
Water level in the bed maintained with outlet structure; 9)
outflow (Vymazal, 1997).
15
Figure 2.7 Typical arrangement of a vertical flow (VF) reed bed system 16
Figure 2.8 Hybrid constructed wetlands for wastewater treatment (based
on Cooper, 1999)
18
Figure 2.9 Floating aquatic weeds (a) water lettuce (Pista stratiotes); (b)
water lily (Nymphaeaceae)
20
Figure 2.10 Emergent aquatic weeds (a) Cattails (Typha latifolia); (b)
common reeds (Phragmites australis)
21
Figure 2.11 Aerobic condition (oxygen from water column if FWS systems
and from atmosphere if SF systems) (Chongrak and Lim, 1998)
23
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Figure 2.12 Aerobic condition (oxygen from plant roots) (Chongrak and
Lim, 1998)
23
Figure 2.13 Simplified wetlands nitrogen cycle (Kadlec and Knight, 1996) 29
Figure 2.14 Phosphorus removal process in constructed wetlands 30
Figure 2.15 Typical layout of landfill 32
Figure 2.16 Classification of landfill structures (Chew, 2005) 38
Figure 3.1 The framework of study 40
Figure 3.2 Limnocharis flava (yellow burhead) 42
Figure 4.1 Percentage of removal for Cell A and B for total suspended
solids (TSS). The FWSCW system can reach until 100%
removal for both cells.
53
Figure 4.2 Concentration of TSS as a function of sampling day for Cell A,
B as well as control unit where the concentration at HRT 9 day
reaches 0 mg/l. It was believed that all the particles are trapped
in the media.
54
Figure 4.3 Percentage removal for Cell A, B and control unit in different
HRT. The percentage removals are increasing steadily where
the system can reach until 100% removal for those cells in
FWSCW.
54
Figure 4.4 The turbidity concentration with different HRT for Cell A, B
and control unit where the leachate concentration are decrease
due to sedimentation and filtration that occur during the
process.
55
Figure 4.5 The percentage of removal of COD for Cell A, B and control
unit. The removals are increase steadily up to 94% removal in
control unit. On the other hand, the removal of control unit
higher than Cell A and B which was probably due to the
presence of non-biodegradable organic compounds in the
landfill leachate.
56
Figure 4.6 The effluent quality for Cell A, B and control unit with
different HRT. The highest COD removal occurs in Cell B at
HRT 9 day with 95.0 mg/l. The effluent quality for HRT 3 day
can be observed in Cell A with 93.0 mg/l.
57
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Figure 4.7 The percentage of removal for NH3-N with different hydraulic
retention time (HRT). The highest removal can be obtained in
Cell A at HRT 6 day. The lowest removal of NH3-N occurs in
control unit with 26% at HRT 6 day.
58
Figure 4.8 The percentage of removal for NO3-N with different hydraulic
retention time (HRT). The highest removal can be obtained in
Cell B at HRT 6 day with removal 98%. The lowest removal of
NO3-N occurs in control unit with 25% at HRT 9 day.
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Figure 4.9 The percentage removal of orthophosphate under different
HRT. The highest removal can be obtained in Cell B at HRT 6
day with removal 98%. The lowest removal of PO43- occurs in
control unit with 23% at HRT 3 day.
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Figure 4.10 The percentage removal of manganese under different HRT.
The highest removal can be obtained in Cell B at HRT 3 day
with removal 91%. The lowest removal of Mn occurs in control
unit with 48% at HRT 9 day.
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Figure 4.11 The percentage removal of iron (Fe) under different HRT. The
highest removal can be obtained in Cell A at HRT 6 days with
removal 94%. The lowest removal of Mn occurs in control unit
with 17% at HRT 3 days.
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LIST OF PLATES
NO. TITLE PAGE
Plate 3.1 Lab-scale constructed wetland 41
Plate 3.2 Dilution of landfill leachate before pour into the cells 43
Plate 3.3 Different concentration during the experiment 44
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LIST OF TABLES
NO. TITLE PAGE
Table 2.1 Some environmental requirements of the aquatic weeds
(adapted from Stephenson et. al., 1980; Reed et. al., 1988
and USEPA, 1988).
24
Table 2.2 Summary of removal mechanisms in wetland for the
pollutant in wastewater (Adapted from Stowell et. al., 1981)
25
Table 2.3 Nitrogen transformation in wetlands
Table 2.4 Landfill leachate composition from three different sources
(Harrington et al., 1986)
34
Table 2.5 Landfill Leachate Composition from new and mature
landfill (Tchobanoglous et. al., 1993).
35
Table 2.6 Landfill Aged Influence on BOD5/COD Ratio and pH of
leachate (Henry, 1987 and Amokrane, 1997)
36
Table 2.7 Classification of Landfill Structure (Pankratz, 2001) 37
Table 3.1 The characteristics of the Limnocharis flava 43
Table 4.1 Characteristics of landfill leachate used in FWSCW
experiments
48
Table 4.2 Effluent concentration after treated by FWSCW for Cell A 49
Table 4.3 Effluent concentration after treated by FWSCW for Cell B 49
Table 4.4 Effluent concentration after treated by FWSCW for control
unit
50
Table 4.5 Removal efficiencies in FWSCW at HRT 3 day 50
Table 4.6 Removal efficiencies in FWSCW at HRT 6 day 51
Table 4.7 Removal efficiencies in FWSCW at HRT 9 day 51
Table 4.8
Significant differences between control, Cell A and Cell B
at HRT 3 days
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Table 4.9 Significant differences between control, Cell A and Cell B
at HRT 6 days
67
Table 4.10 Significant differences between control, Cell A and Cell B
at HRT 9 days
67
Table 4.11 Percentage removal for three cells at HRT 6 days 68
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LIST OF SYMBOLS
Ca Calcium
CW Constructed wetlands
Fe Ferum
FWS Free water surface
FWSCW Free water surface constructed wetland
HRT Hydraulic retention time
mg/l milligram per litre
N2 dinitrogen
N2O Nitrous oxide
NO3- Nitrate
NO2- Nirite
NO2 Nitric oxide
NH4 Ammonium
Mg Magnesium
Mn Manganese
NH3 Ammonia
ppm Part per million
SSF Sub-surface flow
SSFCW Sub-surface flow constructed wetlands
TSS Total suspended solid
Zn Zinc
VF Vertical Flow
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LIST OF APPENDICES
APPENDIX TITLE
PAGE
Appendix A Standard B Under Environmental Quality (Sewage
and Industrial Effluent) Regulations 1979
85
Appendix B Laboratory Analyses 86
Appendix C Analysis of Variance 96
Appendix D Figures Of The Whole Experiment 120
CHAPTER 1
INTRODUCTION
1.1 Reviews
Over the last years, the high population growth rate, industrialization and
urbanization, have been the causes for several environment all over the world.
Nowadays, solid waste management and wastewater treatment are the most
important problems that we are facing. The amount of solid waste produced around
the world is increasing at high rate as well as in Malaysia. Kuala Lumpur and
Selangor produced 7922 tonnes/day in year 2000, and this will increase to 11 728
tonnes/day in year 2010. For the states of Negeri Sembilan, Melaka and Johor, waste
generated for 2000 for 2633 tonnes/day and 3539 tonnes/day are expected by year
2015 (Maseri, 2005). Although there are different alternatives to reduce them or for
their treatment and disposition, landfill is still the most common practice in
developed and developing countries.
However, the landfill method causes generation of leachate (Galbrand, 2003).
According to Pankratz (2001), leachate can be defined as any contaminated liquid
that is generated from water percolation through a solid waste disposal site,
accumulating contaminants and moving into subsurface areas. As these wastes are
compacted or chemically react, bound water is release as leachate. Landfill leachate
2
refers to the liquid that seeps through a landfill site and enters the environment. This
liquid may already be in the material dumped into the landfill, or it may be the result
of rainwater entering the landfill, filtering through the waste material and picking up
additional chemicals before leaking out into the environment. Landfill leachate that
escapes from the environment is most likely to eventually mix with the groundwater
near the site. The quantity of these leachates is small as compared to others
wastewater, but their contents are extremely hazardous (Tizaoui, at el., 2006).
Landfills are potential threats to groundwater quality (Howard, 1997), the
primary concern being the production and treatment of leachate (Eyles and Boyce,
1997). Major environmental problems have arisen from the production and migration
of leachates from landfill sites and subsequent contamination of surrounding land
and water (McBean et al., 1995). To prevent the adverse impacts of landfill leachate
on aquatic life and degradation of water quality, landfill leachate has to be collected
and treated before final discharge into the environment (Sartaj, 2001).
Conventional treatment systems are costly and require a long-term
commitment. Moreover, the great variations in strength and flows of leachate as well
as its toxic effect, due to presence of high concentrations of heavy metals and/or
organic substances, make the use of these systems undesireable (Vesilind et al.,
2002; Tchbanoglous et al., 1993). Many landfill operators are now considering non-
conventional systems such as engineered constructed wetlands, which are low
energy, do not require chemicals, and can satisfactorily address the leachate
management problems (Sartaj, 2002). However, the modern landfill sites require that
the landfill leachate to be collected and treated. Since there is no method to ensure
that rainwater cannot enter the landfill site, landfill sites must now have an
impermeable layer at the bottom.
1.2 Constructed Wetland and Landfill
The role of wetlands in water resource management is fact gaining ground
resulting in the construction wetlands in most developed countries. Constructed
3
wetlands are man-made system that involves altering the existing terrain to simulate
wetlands conditions. They primarily attempt to replicate the treatment that has been
observed to occur when polluted water enters the natural wetlands (Chew, 2006).
Constructed wetlands have been used as an attractive low-cost method for
controlling water pollution from both point and nonpoint sources (Olson, 1992;
Mitsch, 1992). Dundabin and Bowmer (1992) have revealed that constructed wetland
also show good potential for concentrating metals from industrial wastewaters.
Wetlands prevent the contamination of groundwater or to prevent groundwater from
infiltrating into the wetland (Kadlec et al., 2000). As reported by Olson (1992),
constructed and natural wetlands also can contribute in reducing heavy metal and
nutrient significantly to watershed water quality. On the other hand, constructed
wetlands are also used to improve or restore some water bodies such as rivers and
water basins (Nairn and Mitsch, 2000; Mitsch et al., 2005 and Mitsch and Day,
2006).
Among the aquatic treatment systems, constructed wetlands have a greater
potential in wastewater treatment because they can tolerate higher organic loading
rate and shorter hydraulic retention time with improved effluent characteristics
(Chongrak and Lim, 1998).
The treatment of industrial and domestic wastewaters by passage through
beds containing plants of the common reed (Phragmites australis), reedmace (Typha
latifolia), or other species, has been widely practised in recent years, with varying
degrees of success (Barr and Robinson, 1999). This has often been shown to limit the
value of reed beds for treatment of raw landfill leachates. Engineered wetlands do
however; have considerable capability for secondary polishing of leachates that have
been pretreated in aerobic biological plants and for older leachates (Barr and
Robinson, 1999).
There are two types of constructed wetlands: free water surface (FWS)
wetlands also known as surface flow wetlands) and subsurface flow (SSF) wetlands
(also known as root zone method wetlands or rock-filters) (Liehr et. al., 2000). FWS
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systems consist of several basins or cells with the water surface being 0.12 – 2.0
metres above the substrate (Tousignant et. al., 1999).
However, both surface-flow and subsurface-flow constructed wetlands have
been identified as promising technologies for the treatment of landfill leachate
(Kadlec and Knight, 1996). Constructed wetlands have a small ecological footprint,
utilize “low-tech” technology, and have an aesthetic value similar to that of natural
wetlands. The application of wetland technology for treating landfill leachate is still
developing (Nivala, et al., 2006). Wetland also was categorized in the Best
Management Practices (BMP) which is one of the best to reduce non-point source
pollution (Ayob and Supiah, 2005).
1.3 Objectives of the Study
The aim of this study was to establish a diverse, self-sustaining, locally-
modelled, native vegetation community bearing biological integrity treatment
wetland site that effectively decontaminate the leachate input via phytoremediative,
physiochemical and biophysical means. The hypothesis of this study is that “the
selected native vegetation and vegetation establishment strategy will yield a
successfully established site bearing biological integrity and that a naturalized system
supporting biological integrity will effectively remediate the characterized
contaminated leachate input”.
The purpose of this project was to evaluate the efficiency in the context of
treating real landfill leachate on-site using a laboratory scale system. The more
specific goals of the study are given below:
a) To investigate the feasibility of applying free water surface constructed
wetland system to treat landfill leachate containing high organic matters and
nutrient, under different concentration of leachate;
5
b) To determine the relationship between removal efficiency and different
hydraulic retention time (HRT).
1.4 Scope of Study
This study comprises of a series of laboratory scale experiment. Leachate from a
municipal solid waste landfill will be used. This study will cover:
a) A laboratory scale wetland which will be developed for the treatment of
leachate;
b) Each system contained 2 cells. Each cells were planted with same number of
plant 40 no. to 80 no. of plant.
c) The efficiency of landfill leachate treatment system is analysed in terms of
ammonia nitrogen (NH3-N), nitrate nitrogen (NO3--N), orthophosphates
(PO43-), COD, manganese (Mn), and iron (Fe). HACH DR/4000
spectrophotometer equipment was used for analysis of each particular
parameter;
d) The vegetation species that was used in this study is Limnocharis flava;
e) All experiments were carried out in Environmental Engineering Laboratory,
Faculty of Civil Engineering, Universiti Teknologi Malaysia.
1.5 Problem Statement
As cities are growing in size with a rise in the population, the amount of
waste generated is increasing becoming unmanageable. The local corporations have
adapted different methods for the disposal of waste such as open dumps, landfills,
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sanitary landfills, as well as incineration plants. Besides, landfilling methods will
generate a leachate and it will contaminate the groundwater table. These leachates
may migrate from the refuse and contaminate surface and ground waters, which may
affect human health and the aquatic environment. Treatment of these leachates in
classical wastewater treatment plants is rarely practiced due to the nature and high
levels of pollutants present in them (i.e. high COD, low biodegradability, heavy
metals, pathogens, etc.). Dedicated treatment facilities are therefore required before
the leachate being discharged to the environment or to the sewer system. As an
alterative, constructed wetlands are suitable for treating leachate from landfill sites
which can be very harmful if not treated properly. The problem with leachate
treatment is that leachate changes in terms of strength, biodegradability, and toxicity
as the wastes in the landfill age over time. Also, bearing in mind that landfilled
wastes may take up to a hundred years to stabilize.
CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
Constructed wetlands treat a wide variety of wastewaters and runoff waters
using emergent plants. Free water surface (FWS), subsurface flow (SSF), and
vertical flow (VF) constructed wetland all use a combination of fixed-film biological
activity and physical, chemical, or photochemical mechanisms. The treatment of
landfill leachate is one particular application for which constructed wetlands have
been used widely (Crites, 2005).
The characteristics and flow of landfill leachates depend of the composition
of solid wastes, precipitation, runoff, age of the landfill and permeability and type of
cover. Solid waste composition varies substantially with socio-economic conditions,
location, season, waste collection and disposal methods, sampling and sorting
procedures and many others factors (El-Fadel et al., 1997). In addition to the leachate
generation induced by precipitation, it is also produced as a result of biochemical
processes that convert solid materials to liquid forms.
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2.2 What is Constructed Wetlands?
Natural wetlands are called by other names such as bogs, swamps, and
marshes. Bogs occur at higher elevations and are described as spongy, with poorly
drained soil. Swamps are characterized by the presence of trees, while marshes have
a lot of sedges and grasses with trees growing on the edges of the wetland. Nivala et
al (2006) have revealed that constructed wetlands have a small ecological footprint,
utilize “low tech” technology, and have an aesthetic value similar to that of natural
wetlands. In Malaysia, we have one man-made wetlands called Putrajaya Wetland.
Constructed wetlands are engineered systems that have been designed and
constructed to utilize the natural processes involving wetland vegetation, soils, and
their associated microbial assemblages to assist in treating wastewater (Vymazal, J.,
2006). Constructed wetland technology is more widespread in industrialized
countries due to more stringent discharge standards, finance availability, change in
tendency to use on-site technologies instead of centralized systems, and the existing
pool of experience and knowledge based on science and practical works (Korkusuz
et. al., 2005).
Constructed wetlands are becoming increasingly common features emerging
in landscapes across the globe. Although similar in appearance to natural wetland
systems (especially marsh ecosystems), they are usually created in areas that would
not naturally support such systems to facilitate contaminant or pollution removal
from wastewater or runoff (Hammer, 1992; and Mitsch and Gosselink, 2000).
According to Lim et. al. (2003), the constructed wetlands have higher tendency o
remove pollutants such as organic matters, suspended solids, heavy metal and other
pollutants simultaneously. Some of the studies show that the ability of wetland
systems to effectively reduce total suspended solid, biochemical oxygen demand
(Watson et al., 1990 and Rousseau, 2005), and fecal coliform (Nokes et. al., 1999
and Nerall et. al., 2000) are well established. Nitrogen (ammonia and total nitrogen)
and phosphorus are processed with relatively low efficiency by most wetland
systems (Steer et al., 2005).
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Fields (1993) stated that constructed wetlands are built specifically for water
quality improvement purposes, typically involving controlled outflow and a design
that maximizes certain treatment functions. In addition to this, wetlands are usually
utilized as secondary and even tertiary treatment because of toxic effects on the
aquatic plants due to high organic loading of the influents (Solano et. al., 2004).
2.3 Types of Constructed Wetland
There are several types of constructed wetlands; surface flow wetlands,
subsurface flow wetlands, and hybrid systems that incorporate surface and
subsurface flow wetlands. Constructed wetland systems can also be combined with
conventional treatment technologies (Davis, 1995) The basic classification is based
on the type of macrophytic growth, further classification usually based on the water
flow regime (Vymazal, J. 2006) as illustrate in Figure 2.2.
Figure 2.1 shows the typical surface flow (SF) and subsurface flow (SSF)
constructed wetlands. Constructed wetland design include horizontal surface and
sub-surface flow wetlands are similar to natural marshes as they tend to occupy
shallow channels and basins through which water flows at low velocities above and
within the substrate. The basins normally contain a combination of gravel, clay- or
peat-based soils and crushed rock, planted with macrophytes (Shutes, 2001).
Figure 2.1: Typical surface flow and subsurface flow constructed wetlands (Source: Water pollution control federation, 1990)
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Surface flow (Free water surface)
Subsurface flow
Constructed wetlands
Free floating plants
Floating leaves plants
Emergent plants
Submerged plants
Vertical flow Horizontal flow
Upflow
Downflow
Hybrid systems
Figure 2.2: Classification of constructed wetlands for wastewater
treatment (Vymazal, 2001)
2.3.1 Free Water Surface Wetlands (FWS)
Free water surface (FWS) wetlands are treatment wetlands in which the
surface water flowing through them is exposed to the atmosphere. They typically
consist of several basins or cells with the water surface being 0.15 to 2.0 metres
above the substrate (Tousignant et al., 1999). The near surface layer is aerobic while
the deeper waters and substrate are usually anaerobic (Galbrand, 2003 and Chew,
2006). As reported by Vymazal et. al. (2006), in free water surface wetlands, oxygen
is mainly supplied to the wetland through algal photosynthesis and atmospheric
diffusion.
The FWS wetlands technology started with the ecological engineering of
natural wetlands wastewater treatment. Constructed FWS treatment wetlands mimic
the hydrological regime of natural wetlands (Noor, 2006). In surface flow (SF)
wetlands, water flows over the soil surface from an inlet point to an outlet point or, in
11
a few cases, is totally lost to evaporation and infiltration within the wetlands (Chew,
2006 and Nazaitulshila, 2006). As stated by Lim et al. (1998), the FWS system
consist of basins or channels and barriers such as constructed clay layer or
geotechnical material to prevent seepage. Figure 2.3 shows the free water surface
constructed wetland.
These systems are primarily constructed to treat municipal wastewater, mine
drainage, urban storm water, agricultural runoff and livestock wastes, and landfill
leachate (USEPA, 2000). Figure 2.4 shows the free water surface constructed
wetlands in a foreign country.
Free water surface wetlands are sometimes called surface flow wetlands. The
advantages of surface flow wetlands are that their capital and operating costs are low,
and their construction, operation, and maintenance are straightforward (Davis, 1995).
An addition to, Galbrand (2003) has revealed that there are a few more advantage of
using FWS such as (a) significant reduction in the levels of nitrogen and
phosphorus, metals, persistent organic and fecal coliforms, (b) superiority in their
abilities to remove biochemical oxygen demand (BOD), chemical oxygen demand
(COD), and total suspended solids (TSS).
The main disadvantage of surface flow systems are (a) require a large land
area than other systems (Davis, 1995; and Galbrand, 2003), (b) wastewater are
exposed and are therefore accessible to humans and animals, hence it may not prove
prudent to establish these wetlands in high use area such as parks, playgrounds, or
similar public facilities, (c) pollutants such as phosphorus, metals and some
persistent organics can become bound in wetland sediments and accumulate over
time (USEPA, 2000 ; Davis, 1995; and Liehr et al., 2000). Moreover, this system
will contribute to the odour problem and as attraction of unwanted pests such as
mosquitoes that breed easily in the water.
12
Figure 2.3: Free water surface flow (FWS) constructed wetland
Figure 2.4: The free water surface constructed wetlands in a foreign
(Source: Earthpace Resources)
2.3.2 Sub-Surface Flow Wetlands (SSF)
Many of the earliest treatment wetlands in Europe were subsurface flow
(SSF) systems constructed to treat mechanically pretreated municipal wastewater as
shown in Figure 2.5. Moreover, the subsurface flow constructed wetlands first
emerged as a wastewater treatment technology in Western Europe based on research
13
by Seidel commencing in the 1960s, and by Kickuth in the late 1970s and early
1980s as reported by Sherwood (1993). Soil and gravel-based SSF wetlands are still
the most prevalent application of this technology in Europe. SSF wetlands that use
gravel substrates have also been used extensively in the United States. According to
Liehr et al. (2000), a SSF system consists of a sealed basin with a porous substrate of
rock, grave or coarse sand planted with emergent macrophytes such as reeds,
Eurasian watermilfoil and duckweeds. This technology is generally limited to
systems with low flow rates and can be used with less than secondary pretreatment.
Subsurface flow wetlands differ from FWS wetlands in that they incorporate
a rock or gravel matrix that the wastewater is passed through in a horizontal or
vertical fashion (DeBusk et.al, 2001). Unless the matrix clogs, the top layer of the
bed in horizontal flow systems will remain dry. The SSF configuration offers several
advantages, including a decreased likelihood of odour production and no insect
proliferation within the wetlands as long as surface ponding is avoided. Unlike FWS
wetlands, SSF systems provide no aesthetic or recreational benefits and few, if any,
benefits to wildlife.
Figure 2.5: The subsurface constructed wetlands in a foreign country.
(Source: USGS)
Subsurface flow wetlands continue to provide effective treatment of most
wastewater constituents through the winter in temperature climates. The subsurface
microbial treatment processes still function, albeit at a reduced rate, even when the
14
surface vegetation has senesced or died, and the matrix surface is covered with snow
and ice. Subsurface flow wetlands also can be operated in a vertical flow fashion
which can reduce matrix clogging problems and enhance certain contaminant
removal processes such as nitrification.
Because of the high cost of the gravel or rock matrix, SSF wetlands never
attain the large spatial footprint of the large FWS wetlands. Concerns over matrix
clogging and the potential high cost of renovation also limit the deployment of
extremely large SSF wetlands. However, SSF are finding increased use for small
applications, such as for small communities or single family homes. The limitations
of septic systems for nutrient control have become more apparent in the past two
decades (Hagedorn et.al., 1981), and SSF wetlands are one technology that is being
deployed to improve nutrient removal performance (Mitchell et.al., 1990).
Subsurface flow systems are the only wetlands configuration suitable for this
purpose, because they crate no standing water, thereby limiting the likelihood of
human exposure to wastewater pathogens (House et.al., 1999).
a) Horizontal-flow systems (HF)
The system is called horizontal flow because the wastewater enters the inlet
and flows slowly through the porous medium under the surface of bed in an ore or
less horizontal way until it flows out through the outlet. As the wastewater flows
from the inlet to the outlet, it comes into contact with three zones, which are aerobic
zones, anaerobic zones and anoxic zones. These zones are categorized as biological
treatment methods (Uygur and Kargi, 2004). Aerobic zones are found in the area
where there are presence of oxygen such as around the roots and rhizomes. As the
wastewater passes through this zone, it is cleaned by microbiological degradation
and by physical and chemical process (Cooper et al., 1990).
Organic compound are degraded aerobically and anaerobically by the bacteria
that are attached to the roots and rhizomes. Components such as nitrogen is removed
by the major process which are nitrification and denitrification and also other
processes such as volatilization, adsorption and plant uptake. Ammonia is oxidized to
nitrate by nitrifying bacteria in aerobic zones and nitrates are converted to nitrogen
15
gaseous by nitrifying bacteria in anoxic zones (Cooper et al., 1990). As for
phosphorus removal, it occurred through ligand exchange reactions. Phosphates
replace water or hydroxyl ions from the surface of Fe and Al hydrous oxides.
The media, which is used in horizontal sub-surface flow constructed wetlands
like gravel and crushed stones do not contain high quantities of Fe, Al or Ca, so the
removal of phosphorus is rather low. Figure 2.6 shows a typical arrangement for the
subsurface constructed wetland with horizontal flow (HF).
Figure 2.6: Longitudinal constructed wetlands with horizontal SSF. Key: 1) Inflow
of mechanically pretreated wastewater; 2) Distribution zone filled with large stone;
3) Impermeable liner; 4) Medium (Gravel, sand, crush stones); 5) Vegetation; 6)
Outlet collector; 7) Collection zones filled with large stones; 8) Water level in the
bed maintained with outlet structure; 9) outflow (Vymazal, 1997).
b) Vertical Flow Systems
Vertical-flow (VF) treatment wetlands are frequently planted with common
reed. Other emergent wetlands plants such as cattail or bulrush can also be used. VF
reed beds typical look like the system show in Figure 2.7. They are composed of a
flat bed of gravel topped with sand, with reed growing at the same sort of densities as
horizontal-flow (HF) systems (Chew, 2006). They are fed intermittently. The liquid
is dosed on the bed in a large batch, flooding the surface. The liquid then gradually
drains vertically down through the bed and is collected by a drainage network at the
base. The bed drains completely free, allowing air to refill the bed. The next dose of
16
liquid trap air this together with the aeration caused by the rapid dosing on the bed
leads to good oxygen transfer and hence the ability to decompose BOD and to nitrify
ammonia nitrogen.
Figure 2.7: Typical arrangement of a vertical flow (VF) reed bed system
As with the horizontal flow (HF) systems, the reeds in vertical flow (VF)
systems will transfer some oxygen down into the rhizosphere, but it will be small in
comparison with the oxygen transfer created by the dosing system. Vertical flow
(VF) treatment wetlands are very similar in principle to a rustic biological filter.
They are less good at the removal of suspended solid and in most cases will be
followed by a horizontal flow bed as part of a multistage treatment wetlands system.
The advantages cited for sub-surface flow (SSF) wetlands are greater cold
tolerance, minimization of pest and odor problems, and possibly, greater assimilation
potential per unit of land area than in surface flow (SF) systems. It has been claimed
that the porous medium provides greater surface area for treatment contact than is
found in surface flow (SF) wetlands, so that the treatment responses should be faster
for sub-surface flow (SSF) wetlands which can, therefore, be smaller than a surface
flow (SF) system designed for the same volume of wastewater. Since the water
surface is not exposed, public access problems are minimal. Several subsurface
systems are operating in parks, with public access encouraged.
17
The disadvantages of sub-surface flow (SSF) wetlands are that they are more
expensive to construct, on a unit basis than surface flow (SF) wetlands. Because of
cost, subsurface wetlands are often used for small flows. Sub-surface flow (SSF)
wetlands may be more difficult to regulate than surface flow (SF) wetlands, and
maintenance and repair costs are generally higher than for surface wetlands. A
number of systems have had problems with clogging and unintended surface flows.
2.3.3 Hybrid Systems
Various types of constructed wetlands may be combined in order to achieve
higher treatment effect, especially for nitrogen (Vymazal, 2005). Single stage
systems require than all of the removal processes occur in the same space. In hybrid
or multistage systems, different cells are designed for different types of reactions.
Effective wetland treatment of mine drainage may require a sequence of different
wetland cells to promote aerobic and anaerobic reactions as may the removal of
ammonia from agricultural wastewater. However, hybrid systems comprise most
frequently VSSF (VF) and HSSF (HF) systems arranged in a stage manner as shown
in Figure 2.8. However, there are been a growing interest in achieving fully nitrified
effluents (Vymazal, 2006). Vymazal (2005) revealed that there are now many fine
examples of HF systems for secondary treatment and they proved very satisfactory
where the standard required only BOD5 and SS removal.
However, there has been a growing interest in achieving fully nitrified
effluents. HF systems cannot do this because of their limited oxygen transfer
capacity. Moreover, Vymazal (2005) add that VF systems, on the other hand do
provide a good conditions for nitrification but no denitrification occurs in these
systems. In combined systems (hybrid system), the advantages of HF and VF
systems can be combined to complement each other. A research done by Cooper
(1999, 2001), it is possible to produce an effluent low in BOD, which is fully
nitrified and partly denitrified and hence has a much lower total-N concentrations.
18
Figure 2.8: Hybrid constructed wetlands for wastewater treatment (Cooper, 1999)
2.4 Theory of Operation
The deliberate uses of wetlands (both natural and constructed) as biological
treatment systems for effluent purification have developed rapidly over the last 25-30
years (Brix, 1993). Theoretically, wastewater flows through the root zone, which the
plants supply with oxygen and channels for wastewater flow. The efficiency and cost
effectiveness of this method of treatment are highly controversial. Although many
sites are in operation, the tremendous variation in site design, soil type, loading rate,
and wastewater characteristics have made comparison difficult. Further studies are
needed to evaluate optimal loading regimes and the specific area needed for
maximum performance efficiency (Forsburg, 1996).
Several types of natural wetlands, such as southern swamps, bottomland
hardwood forests, freshwater marshes, northern bogs, and brackish and saltwater
marshes have been used for the improvement of water quality for centuries. Because
of their transitional position between terrestrial and aquatic ecosystem, some
wetlands have been subjected to both municipal and industrial wastewater
19
discharges. Wetland has also received agricultural runoff, combined sewer overflow,
stormwater runoff, mine drainage, and other sources of water pollution (Bastian et
al., 1989). In early 1980’s there were over 500 natural wastewater treatment wetlands
in operation in U.S (U.S EPA, 1983).
There are still too few data from natural wetland leachate system to allow
indisputable predictions of the treatment performance and the effects of leachate
discharge on the receiving ecosystems. Exploiting this technology without adequate
evaluation could to unfortunate results. Also, using natural wetlands for wastewater
treatment has several advantages (Forsburg, 1996).
Wetland systems are effective in reducing many contaminants (e.g., nitrogen,
phosphorus, trace organic compounds, metals, and pathogens) (Wildeman and
Laudon, 1989). The pollutants in these systems are removed through a combination
of physical, chemical, and biological processes. Low-cost immobilization of
pollutants for long periods of time is the goal of using constructed wetlands for water
pollution treatment. As reported by Kadlec and Knight (1996), some possible metal
removal mechanisms associated with municipal solid waste (MSW) landfill leachate
include bioaccumulation in plants, adsorption in sediments, precipitation as insoluble
salts, incorporation by a range of organic materials such as algae, detritus and
bacteria.
Bioaccumulation and adsorption have been reported to have finite capacities
to retain metals and, if dominant in controlling metal retention, may indicate poor
long-term treatment performance. But metal removal in constructed wetland systems
has received little attention to date because most existing systems treat wastewaters
having low concentrations of heavy metals.
2.5 Aquatic Macrophytes
Thousands of plants have adapted to life in water or wetlands, with a
significant proportion of them occurring only in wetlands and shallow water. Many
20
wetlands are readily identified by vegetation and traditional methods relied on plants
for wetland identification and delineation. Plants also serve as a basis for wetland
classification. Rooted emergent aquatic macrophytes, such as common reeds
(Phragmites australis), cattails (Typha latifolia) and bulrushes (Scirpus lacustris),
are the dominant plants in wetlands (Mitsch and Gosselink, 1993). These species
produce aerial stems and leaves, and an extensive root and rhizome system
(Forsburg, 1996). According to Cronk and Fennessy (2001), the emergent plants are
rooted in the soil where their leaves and stems which are the photosynthetic parts of
the plants are called aerial.
Plants growing in wetlands and water are technically called hydrophytes.
Most wetland plants do not grow strictly in water or very wet soils, but also grow in
terrestrial habitats, especially under mesic soil conditions. Many of these species are
more common on the latter sites, but have populations that tolerate varying degrees
of soil wetness. Unfortunately, due to lack of distinctive morphological differences,
individuals of these wetland populations can only be recognized as hydrophytes
when associated with more typical hydrophytic species or after identification of
hydric soils (i.e., periodically anaerobic soils due to excessive wetness) and other
reliable signs of wetland hydrology at a given location. The categories used to group
wetland plants include emergent, submerged, floating-leaved, and floating. The
general characteristics of each group are described in next sub-section.
The major types of aquatic macrophytes are submerged, floating and
emergent weeds; some of these are shown in Figure 2.9 and 2.10, respectively.
Figure 2.9: Floating aquatic weeds (a) water lettuce (Pistia stratiotes); (b) water lily
(Nymphaeaceae)
(a) (b)
21
Figure 2.10: Emergent aquatic weeds: (a) Cattails (Typha latifolia);
(b) Common reeds (Phragmites australis)
(a) (b)
Submerged plants are either suspended in the water column or rooted in the
bottom sediments. In submerged species, all photosynthetic tissues are normally
underwater (Cook, 1996). These species are not effective for wastewater treatment
due to the requirement of light penetration into the water bodies. The second types of
aquatic weeds, namely the floating type, have their root portions submerged but not
attached to the soil. According to Galbrand (2003), there are two sub-types of
floating weeds, i.e floating unattached weeds where their roots are hanging free in
the water and are not anchored in the sediments whereas the floating attached weed,
their leaves are floating on the water surface while their roots are anchored in the
substrate.
Emergent plants are rooted in the soil with basal portions that typically grow
beneath the surface of the water, but whose leaves, stems (photosynthetic parts), and
reproductive organs are aerial. These plants tend to have a higher potential in
wastewater treatment because they can serve as a microbial habitat and as a filtering
medium (Chongrak and Lim, 1998). Cattails (Typha spp.) and reeds (Phragmites
app.) are easy to propagate and produce a large biomass. They thrive under a wide
range of water quality and other environmental conditions, including acidic waters
with iron concentrations of up to 100 mg/l. The rhizospheres of Typha and
Phragmites app. provide an effective matrix which traps and filters sediment
particles and associated metals. Moreover, bulrushes (Scirpus spp.) are also easy to
22
propagate, produce a large biomass, and can thrive under a wide range of water
quality and environmental conditions. They are reported to be more susceptible to
transplanting stress than cattails and have a slower rate of spread.
The floating-leaved plants are also known as floating attached (Cronk and
Fennessy, 2001). The plant leaves float on the water’s surface while their roots are
anchored in the substrates. Floating-leaved species shade the water column below
and are often able to outcompete submerged species for light, particularly when
turbidity levels are high and light penetration is reduced (Haslam, 1978). Example of
floating-leaved plants is Nymphaeaceae or better known as water lily as shown in
previous Figure 2.9.
However, the pathway of metal transfer from the sediment and interstitial
water to the roots and rhizomes is still not fully understood and requires further
investigation. The common types of aquatic weeds, their scientific names and some
of the environmental requirements are given in Table 2.1.
2.6 Treatment Process Mechanisme
An understanding of the treatment mechanisms is essential so that the design
of wetland systems can be improved for better treatment performance. The principal
pollutant removal mechanisms operatives in wetland systems are listed in Table 2.2
and they include sedimentation, chemical precipitation, and adsorption, microbial
metabolic activity and plant uptake (Chongrak and Lim, 1998).
2.6.1 Biodegradable Organic Matter Removal
In wetland systems, microbial degradation plays a dominant role in the
removal of soluble/colloidal biodegradable organic matter (BOD or COD) in
wastewater, the remaining BOD associated with settleable solids being removed by
23
sedimentation. Both the SF and FWS systems essentially function as attached growth
biological reactors. For the FWS systems, however, the contribution of suspended
microbial growth in the water column to BOD removal cannot be neglected. The
mechanism of BOD removal in the attached biofilm is similar to that of trickling
filters (Chongrak and Lim, 1998).
Biodegradation takes place when dissolved organics is carried by the
diffusion process into the biofilms on the submerged plant stems (FWS systems), the
root system and surrounding soil or media (Chongrak and Lim, 1998). The role of
wetland vegetations is confined to providing a support medium for microbial
degradation to take place as in Figure 2.11, and to conveying oxygen to the
rhizosphere for aerobic biodegradation to occur in Figure 2.12.
Figure 2.11: Aerobic condition (oxygen from water column if FW
systems and from atmosphere if SF systems) (Chongrak and Lim, 1998)
Figure 2.12: Aerobic condition (oxygen from plant roots)
(Chongrak and Lim, 1998)
S
24
pH
6.3-
10
5.
0-10
7.1-
8.7
5.9-
7.0
3.
5-11
4.5-
7.5
4-10
2-8
5-7.
5 4-
9 5-
7.5
Opt
imum
Wat
er
leve
l, cm
- - - - - -
12-1
00
-3
0-15
0
-10-
10
-7
5-20
0
5-95
Max
imu
m sa
linity
to
lera
nce,
pp
t
15 10 3.
8
2.5
16.6
7 30
45 20 20 -
Surv
ival
*
23-2
6++
- - 10 5 5
12-2
4
10-3
0 - - -
Am
bien
t tem
pera
ture
Des
irabl
e
18-2
6++
15-2
5++
10
-25++
20-3
0
>10
20-3
0
10-3
0
12-3
3
12-2
6
16-2
7
14-3
2
Dis
tribu
tion
Wor
ldw
ide
Wor
ldw
ide
Tem
pera
te re
gion
Tr
opic
al a
nd su
b-tro
pica
l reg
ion
Wor
ldw
ide
W
orld
wid
e W
orld
wid
e W
orld
wid
e
Wor
ldw
ide
Wor
ldw
ide
Wor
ldw
ide
Com
mon
nam
e, sc
ient
ific
nam
e
Pond
wee
d
Pota
mog
eton
spp.
Eu
rasi
an w
ater
mill
foil,
Myr
ioph
yllu
m sp
acitu
m
Coo
ntai
l,
Cer
atop
hyllu
m d
emer
sum
Wat
er h
yaci
nth,
Eich
horn
ia c
rass
ipes
W
ater
fern
A
zolla
app
. D
uckw
ed,
L e
mna
spp.
C
atta
ils,
Ty
pha
spp.
C
omm
on re
ed,
Ph
rgm
ites c
omm
unis
R
ushe
s,
Junc
us sp
p.
Bul
rush
es,
Sc
irpu
s spp
. Se
dges
,
Car
ex s p
p.
Type
s of a
quat
ic
wee
ds
Subm
erge
d
Floa
ting
Emer
gent
Tab
le 2
.1: S
ome
envi
ronm
enta
l req
uire
men
ts o
f the
aqu
atic
wee
ds
(Ada
pted
from
Ste
phen
son
et. a
l., 1
980;
Ree
d et
. al.,
198
8 an
d U
SEPA
, 198
8).
Not
e:
*T
emge
for s
eed
germ
inat
ion;
root
s and
rhiz
omes
can
surv
ive
in fr
ozen
soils
.
+p
pt =
par
ts p
er th
ousa
nd
++W
ater
tem
pera
ture
(onl
y fo
r sub
mer
ged
type
s)
pera
ture
ran
25
Des
crip
tion
Gra
vita
tiona
l set
tling
of s
olid
s (an
d co
nstit
uent
pol
luta
nts)
in w
etla
nd se
tting
s.
Parti
cula
tes f
ilter
ed m
echa
nica
lly a
s wat
er
pass
es th
roug
h su
bstra
te, a
nd ro
ot m
asse
s In
terp
artic
le a
ttrac
tive
forc
es
(van
der
Waa
ls fo
rce)
V
olat
iliza
tion
of N
H3 f
rom
the
was
tew
ater
Fo
rmat
ion
of o
r co-
prec
ipita
tion
with
in
solu
ble
com
poun
ds
Ads
orpt
ion
on su
bstra
te a
nd p
lant
surf
aces
D
ecom
posi
tion
of a
ltera
tion
of le
ss st
able
co
mpo
unds
by
phen
omen
a su
ch a
s UV
irr
adia
tion,
oxi
datio
n, a
nd re
duct
ion
Rem
oval
of c
ollo
idal
solid
s and
solu
ble
orga
nics
by
susp
ende
d, b
enth
ic, a
nd p
lant
-sp
porte
d ba
cter
ia. B
acte
rial
nitri
ficat
ion/
deni
trific
atio
n.
Upt
ake
and
met
abol
ism
of o
rgan
ics b
y pl
ants
. Roo
t exc
retio
n m
ay b
e to
xic
to
orga
nism
of e
nter
ic o
rigin
U
nder
pro
per c
ondi
tions
, sig
nific
ant
quan
titie
s of t
hese
pol
luta
nts w
ill b
e ta
ken
up
by p
lant
s. N
atur
al d
ecay
of o
rgan
ism
s in
an
unfa
vour
able
env
ironm
ent
Bac
teri
al
& v
irus
I P S P
Ref
ract
ory
orga
nics
I S P P S S
Hea
vy
met
als
I P P S
P I P P S
N I S P S
BO
D
I P
Col
loid
al
solid
s
S S S P
Pollu
tant
aff
ecte
da
Sett
leab
le
solid
s
P S
Mec
hani
sms
Phys
ical
Sed
imen
tatio
n
Filtr
atio
n
Ads
orpt
ion
Vol
atili
zatio
n
Che
mic
al P
reci
pita
tion
Ads
orpt
ion
Dec
ompo
sitio
n
Bio
logi
cal b
acte
ria
met
abol
ism
b
Plan
t Met
abol
ism
Plan
t Ads
ortio
n
Nat
ural
die
-off
Tab
le 2
.2: S
umm
ary
of re
mov
al m
echa
nism
s in
wet
land
for t
he p
ollu
tant
in w
aste
wat
er (A
dapt
ed fr
om S
tow
ell e
t. al
., 19
81)
Not
es:
a P =
prim
ary
effe
cts;
S =
seco
ndar
y ef
fect
; I =
inci
dent
al e
ffec
t (ef
fect
occ
urrin
g in
cide
ntal
to re
mov
al o
f ano
ther
pol
luta
nt)
b The
term
met
abol
ism
incl
udes
bot
h bi
osyn
thes
is a
nd c
atab
olic
reac
tions
.
26
2.6.2 Metal Removal Mechanisms
The potential for uptake by vegetation appears to be a small and unimportant
source of metal removal in wetland systems (Dunbabin and Bowmer, 1992). A
preliminary iron mass balance for a constructed wetland receiving AMD emphasizes
the small role of vegetation and the dominant role of sediments in removing and
storing iron (Fennessy and Mitsch, 1992).
Forsburg (1996) reported that the current information suggests there are two
complementary processes for iron and manganese retention and degradation in
constructed wetlands: biologically mediated oxidation and reduction processes. The
anaerobic conditions found in wetlands enhance retention or metals. This coupled
with aerated conditions in the rhizosphere allow many processes to occur
simultaneously. Reduction processes as removal mechanisms, have not been fully
explored (Spratt et al., 1987). Questions remain concerning the exact mechanisms,
controlling factors, and long-term functional capabilities of these processes.
In an experiment to determine if metal uptake by vegetation represents a
major flux of metals out of the ecosystem, Shutes et al. (1993) concluded that the
significance of the uptake of metals in the plant tissue is negligible, as the amount of
metals taken up during a growing season constituted less than 3% of the total content
introduced with the wastewater. Forsburg (1996) suggested that the subsurface
introduction of effluent into CW would maximize the purification potential, and that
metals will become immobilized on the increased sediment – root surfaces.
2.6.3 Removal of Nitrogen
Nitrogen has a complex biogeochemical cycle with multiple biotic/abiotic
transformations involving seven valence states (+5 to -3). The compounds include a
variety of inorganic and organic nitrogen forms that are essential for all biological
life (Vymazal, 2006). The most important inorganic forms of nitrogen in wetlands
are ammonium (NH4+), nitrite (NO2
-) and nitrate (NO3-). Gaseous nitrogen may exist
27
as dinitrogen (N2), nitrous oxide (N2O), nitric oxide (NO2 and N2O4) and ammonia
(NH3).
Removal of nitrogen in wetlands is achieved through three main mechanisms:
nitrification/denitrification, volatilization of ammonia and uptake by plants.
Chongrak and Lim (1998) reported that there is still no general consensus among the
researchers on the relative importance of the removal mechanisms specifically
between nitrification/denitrification and plant uptake.
(a) Nitrogen Transformation in Wetlands
Mitsch and Gosselink (1986) define nitrogen mineralization as the biological
transformation of organically combined nitrogen to ammonium nitrogen during
organic matter degradation. This can be both an aerobic and anaerobic process and is
often referred to as ammonificaton. Mineralization of organically combined nitrogen
releases inorganic nitrogen as nitrates, nitrites, ammonia and ammonium, making it
available for plants, fungi and bacteria. Mineralization rates may be affected by
oxygen levels in a wetland.
Wetzel (1983) defines nitrification as the biological conversion of organic
and inorganic nitrogenous compounds from a reduced state to a more oxidized state.
Nitrification is strictly an aerobic process in which the end product is nitrate (NO3-)
this product is limited when anaerobic conditions prevail (Patrick and Reddy, 1976).
Nitrification will occur readily down to 0.3 ppm dissolved oxygen (Keeney, 1973).
The process of nitrification oxidizes ammonium (from the sediment) to nitrite
(NO2-), and then nitrite is oxidized to nitrate (NO3
-). The overall nitrification
reactions are as follow (Davies and Hart, 1990):
2NH4+ + 3O2 ↔ 4H+ + 2H2O + 2NO2
- (1)
2NO2- + O2 ↔ 2NO3
- (2)
According to Wetzel (1983), denitrification by bacteria is the biochemical
reduction of oxidized nitrogen anions, nitrate-N and nitrite-N, with contaminant
28
oxidation of organic matter. The general sequence as given by Wetzel (1983) is as
follows:
NO3- → NO2
- → N2O → N2 (3)
The end product, N2O and N2 are gases that re-enter the atmosphere.
Denitrification is most commonly defined as the process which nitrate is converted
into dinitrogen via intermediates nitrite, nitric oxide and nitrous oxide (Hauck, 1984;
Paul and Clark, 1996; Jetten et al., 1997). The nitrate can be removed either through
plant uptake as its main nitrogen nutrient or reduce through denitrification process
(Galbrand, 2003). Denitrification occurs intensely in anaerobic environments but will
also occur in aerobic conditions (Bandurski, 1965). As reported by Hammer and
Knight (1994), the denitrification process occurs in anaerobic environment and the
denitrifying bacteria are Pseudomonas, Achtomobacter, Aerobacter, Bacillus,
Proteus and Micrococcus.
Liehr et al. (200) stated that ammonification process can occur in both
aerobic and anaerobic condition. Ammonia volatilization is a physiochemical process
where ammonium-N is known to be in equilibrium between gaseous and hydroxyl
forms (Vymazal, 2006). According to Reddy and Patrick (1984), the losses of NH3
through volatilization from flooded soils and sediments are insignificant if the pH
value is below 8.0. At pH of 9.3 the ratio between ammonia and ammonium ions is
1:1 and the losses via volatilization are significant. Ammonification rates are
dependent on temperature, pH, C/N ratio, available nutrients and soil conditions such
as texture and structure (Reddy and Patrick, 1984). Vymazal (2006) revealed that
algal photosynthesis in wetlands as well as photosynthesis by submerged
macrophytes often creates high pH values during the day. The pH of shallow flood
water is greatly affected by the total respiration activity of all the heterotrophic
organisms and the gross photosynthesis of the sepsis present. The optimal
ammonification temperature is reported to be 40 - 60 ˚C while optimal pH is between
6.5 and 8.5 (Vymazal, 1995). Volatilization of ammonia can be result in nitrogen
removal rates as high as 2.2 g N m-2 d-1. Table 2.3 shows the nitrogen
transformations in constructed wetlands, while Figure 2.13 illustrates the simplified
nitrogen cycle in wetlands.
29
Process Transformation
Volatilization Ammonia-N (aq) ammonia-N (g)
Ammonification Organic-N ammonia-N
Nitrification Ammonia-N nitrite-N nitrate-N
Nitrate-ammonification Nitrate-N ammonia-N
Denitrification Nitrate-N nitrite-N gaseous N2, N2O
N2, Fixation Gaseous N2 ammonia-N (organic-N)
Plant/microbial uptake (assimilation) Ammonia-, nitrite-, nitrate-N organic-N
Ammonia adsorption
• Organic nitrogen burial
• ANAMMOX (anaerobic ammonia
oxidation)
Ammonia-N gaseous N2
Table 2.3: Nitrogen transformations in constructed wetlands (Vymazal, 2006)
Figure 2.13: Simplified wetlands nitrogen cycle (Kadlec and Knight, 1996)
2.6.4 Removal of Phosphorus
Phosphorus in wetlands occurs as phosphate in organic and inorganic
compounds. Free orthophosphate is the only form of phosphorus believed to be
utilized directly by algae and macrophytes and thus represents a major link between
30
organic and inorganic phosphorus cycling in wetlands (Vymazal, 2006). Meanwhile,
according to Chongrak and Lim (1998), the phosphorus removal mechanism in
wetland systems include vegetative uptake, microbial assimilation, adsorption onto
soil (mainly clay) and organic matter and precipitation with Ca2+, Mg2+, Fe2+ and
Mn2+. Adsorption and precipitation reactions are the major removal pathways when
the hydraulic retention time is longer and finer-textured soils are being used, since
this allows greater opportunity for phosphorus sorption and soil reactions to occur
(Reed and Brown, 1992).
Similar to that of nitrogen removal, the relative importance of phosphorus
removal via plant uptake pathway is still a subject for debate. Nonetheless, it is the
only mechanism by which phosphorus is removed from the wetland systems.
Adsorption and precipitation reactions merely trap the phosphorus in the wetland
soil. Once the storage capacity has been exceeded, the soil/sediment has to be
dredged for ultimate disposal (Lim and Chongrak, 1998). Figure 2.14 depicted the
removal process of phosphorus in constructed wetlands.
Figure 2.14: Phosphorus removal process in constructed wetlands
31
2.6.5 Solids Removal
Settleable solids are removed easily via gravity sedimentation as wetland
systems generally have long hydraulic retention times. Nonsettling/colloidal solids
are removed via mechanisms which include: straining (if sand media is used);
sedimentation and biodegradation (as a result of bacterial growth); and collisions
(inertial and Brownian) with an adsorption (Van der Waals forces) of other solids
(plants, soil, sand and gravel media). For gravel media which forms an important
component in a subsurface flow wetland system, Sapkota and Bavor (1994)
suggested that the suspended solids removal is primarily by sedimentation and
biodegradation similar to what is occurring within a trickling filter.
On the other hand, the solid removal mechanism are very depends on the
sizes and nature of solids present in the wastewater, as well as the types of filter
media used. In all cases, wetland vegetation has a negligible role to play in solids
removal.
2.7 Landfill Leachate
Prior to 1965 very few people were aware of the fact that water passing
through solid waste in a sanitary landfill would become highly contaminated. This
water, termed leachate, was generally not a matter of concern until few cases of
water pollution were noted where leachate had caused harm (Boyle and Ham, 1974).
Boyle and Ham (1974) also reported that many contaminants released from sanitary
landfill, if allowed to migrate, may pose a severe threat to surface and ground water.
Kouzeli-Katsiri et al. (1999) also revealed that the production of leachate can
becomes harmful to all organisms if it moves out of landfill into the surrounding soil.
The composition and quantity of leachate is subject to seasonal and even
daily fluctuations, which significantly impact the design of leachate treatment plants.
Figure 2.15 depicted a typical layout of a landfill.
32
Figure 2.15: Typical layout of landfill
2.7.1 Leachate Generation
Organic and mineral compounds generated as products of waste
mineralization within biological processes and accompanying physical and chemical
processes are washed out by percolating rainwater through the deposit of wastes in
landfill and form heavy polluted waters, or leachate. Leachate generation
accompanies landfill during its exploitation and a long time after its closing and
recultivation. According to Lu et al. (1985), there are a number of factors that
contribute to leachate generation such as availability of water, landfill surface
condition, refuse condition and underlying of soil conditions. The composition and
amount of leachate depend on many factors such as quality of wastes and its
crumbling, techniques of landfilling and degree of waste compaction, age of landfill,
biochemical and physical processes of waste decomposition, moisture and absorption
capacity of wastes, precipitation, humidity, and evapotranspiration rate, topography
of landfill site, lining system, hydrogeology, vegetation.
Precipitation and climate have the strongest influence on leachate generation,
causing the amount to vary during the year. Absorption capacity of wastes is another
affecting leachate production. Initial moisture of municipal wastes depends on type
of waste, seasonal trends, and treatment after collection and amounts on average to
33
35% of dry weight (Blakey, 1992). Additionally, wastes can absorb liquid up to the
moment when downward percolation begins. The absorption capacity is influenced
by waste density and pathways of liquid infiltrating through the deposit of wastes.
Generally, an increase of waste density decreases leachate production (Harrington,
1986 and Blakey, 1992).
The amount of leachate generated in municipal landfill can be calculated with
the following water balance equation (Blakey, 1992):
)( WUETURPPL ∆++∆+−= (4)
where: LP = leachate production, P = precipitation, R = surface runoff, ∆U = changes
in soil moisture storage, ET= evaporation from soil/evapotranspiration from a
vegetated surface, and ∆UW = changes in moisture content in wastes.
Landfill leachates are due to toxicity, classified as problematic wastewaters
and represent a dangerus source of pollution for the environment. Their purification
is difficult and often insufficient; therefore they seriously endanger the quality of the
surface and underground waters (Tjasa et.al., 1997).
The characteristics of the landfill leachates can usually be represented by the
basic parameters COD, BOD, ratio of BOD/COD, colour, NH3-N, pH, alkalinity,
oxidation-reduction potential and heavy metal (Wang, 2004).
2.7.2 Leachate Composition
More than 200 organic compounds have been identified in leachate. They
may be classified as cyclic hydrocarbons, bicyclic compounds, aromatic
hydrocarbons, substituted benzenes, alcohols and ethers, cyclic ethers, ketones and
ene-ones, acids and esters, phenols, phthalates, furans and nitrogen-, phosphorus-,
sulfur-, and silica-containing compounds, and others that remain unidentified.
34
rity
n a
ver,
ses
an
d a
of
osit
of
tive
on
in
Among the abovementioned compounds are 35 substances recognized as prio
pollutants (Michal, et. al, 2004).
Many factors influence leachate production and composition, resulting i
different amount and quality of leachate produced in a particular landfill. Moreo
the composition of leachate is changed significantly by the anaerobic proces
occurring in the deposit of wastes and age of landfill (Harrington, 1986). As
example, Table 2.5 shows the composition of leachate for a new landfill an
mature landfill. Moreover, according to Harrington et al. (1986), the composition
leachate is change significantly by the anaerobic processes occurring in the dep
of wastes and age of landfill, as an example, Table 2.4 shows the composition
leachate from different sources, which point at highly varying ranges of respec
parameters. The leachate characteristics showed a wide variation depending
tropical climatic changes such as monsoon and dry periods, similar to those found
other places (Tchobanoglous et. al., 1993).
Table 2.4: Landfill leachate composition from three different sources
(Harrington et al., 1986)
Parameter Range Range Range
pH 4.5-9.0 5.8-7.5 5.3-8.5
COD (mg/L) 500-60,000 100-62,000 150-100,000
BOD (mg/L) 20-40,000 2-38,000 100-90,000
Sulfate (mg SO4/L) 10-1,750 60-460 10-1,200
Chloride (mg Cl/L) 100-5,000 100-3,000 30-4,000
Ammonia nitrogen (mg N-NH4/L) 30-3,000 5-1,000 1-1,200
Young landfill leachate contains large amount of free volatile fatty acid,
resulting in high concentration of COD, BOD, NH3-N and alkalinity, a low
oxidation-reduction potential and black colour. Therefore, biological processes are
commonly employed for young landfill leachate treatment to remove the bulk
biodegradable organics (Wang, 2004). Old landfill leachate or biologically treated
young landfill leachate has a large percentage of recalcitrant organics molecules. As
a result, this kind of leachate is characterized by high COB, low BOD, fairly high
NH3-N and alkalinity, low ratio of BOD5/COD, a high oxidation-reduction potential
35
and dark brown or yellow colour. The treatment processes for this kind of leachate
include chemical precipitation and coagulation, chemical oxidation, electrochemical
oxidation, reverse osmosis and nanofiltration (Wang, 2004).
Table 2.5: Landfill Leachate Composition from new and mature landfill
(Tchobanoglous et. al., 1993).
BOD
TOC
COD
Tota
Orga
Amm
Nitra
Tota
Orth
Alka
pH
Tota
Calc
Mag
Pota
Sodi
Chlo
Sulfa
TotaAll un
A
stability o
pH of lea
and wast
presented
New landfill < 2 years Constituent
Range Typical
Mature landfill
years > 10
5 2000-30000 10000 100-200
1500-20000 6000 80-160
3000-6000 18000 100-500
l suspended solid 200-2000 500 100-400
nic nitrogen 100-800 200 20-40
onia nitrogen 10-800 200 20-40
te 5-40 25 5-10
l phosphorus 5-100 30 5-10
ophosphorus 4-80 20 4-80
linity as CaCO3 1000-10000 3000 200-1000
4.5-7.5 6 6.6-7.5
l hardness 300-1000 3500 200-500
ium 200-3000 1000 100-400
nesium 50-1500 250 50-200
ssium 200-1000 300 50-400
um 200-2500 500 100-200
ride 200-3000 500 100-400
te 50-1000 300 20-50
l iron 50-1200 60 20-200 its in mg/l
s landfill ages, the pH of leachate also undergoes changes. Owing to the
f the second, methanogenic phase of anaerobic waste decomposition, the
chate increases to 8.5-9.0 (Henry, 1987). The degree to which landfill age
e decomposition influence the BOD5/COD ratio and pH of leachate is
in Table 2.6.
36
Table 2.6: Landfill Aged Influence on BOD5/COD Ratio and pH of leachate
(Henry, 1987 and Amokrane, 1997)
YMO
Landfill ag
e Degree of waste decomposition
pH of leachate
BOD5/COD ratio
oung (<5years) Fresh, not decomposed wastes <6.5 0.7 ature (ageing) Partially decomposed 6.5-7.5 0.5-0.3 ld (>10years) Well-stabilized wastes >7.5 0.1
2.8 Leachate Contol Strategies
The leachate control strategies cover of waste input, control of water input,
control of landfill reactor and control of leachate dischage into the environment
(Christensen et al., 1992).
To control waste input, the amount of waste to be landfilled should be
reduced to a minimum level (Wang, 2004). The reduction of waste can be done by
separation of collection activities, recycling centers, incineration and composting.
Separation of hazardous fractions of municipal waste such as batteries, paint, expired
medicine and pesticide can reduce heavy metal and other toxic compounds
concentration in leachate.
To control water input depends on the quality of waste to be landfilled (SBC,
2002). For non-biodegradable waste, water infiltration should be prevented through
introduction of top sealing. For biodegradable waste, water input must be given so
that a certain degree of biostabilization can be obtained. To control the water input,
there are several important parameters to be considered. The parameters are siting of
landfill in low precipitation areas, usage of cover and topsoil systems that are
suitable for vital vegetation and biomass production, vegetation of the topsoil with
species which optomize the evaporation effect, surface lining in critical hydrological
conditions, limitation on sludge disposal, surface water drainage and diversion high
compaction of the refuse in the place and measures to prevent risks of cracking
owing to differential settlement (Christensen et al., 1992).
37
2.9 Type of Landfill
Landfill is land disposal sites that employ an engineering method of solid
waste disposal to minimize environmental hazards and protect the quality of surface
and subsurface waters (Pankratz, 2001).
Landfill sites are classified into 5 types according to structure as shown in
Table 2.7 and Figure 2.16. In terms of quality of leachate and gases generated from
landfill site, either semi-aerobic or aerobic landfill method is desirous.
Table 2.7: Classification of Landfill Structure (Pankratz, 2001)
Types of Landfill Classification Anaerobic landfill
Solid wastes are filled; in dug area of plane field or valley. Wastes are filled with water and in anaerobic condition.
Anaerobic sanitary landfill
Anaerobic landfill with cover like sandwich shape. Condition in solid waste is same as anaerobic landfill.
Improved anaerobic sanitary landfill (Improved sanitary landfill)
This has leachate collection system in the bottom of the landfill site. Others are same as anaerobic sanitary landfill. The condition is still anaerobic and moisture content is much less than anaerobic sanitary landfill.
Semi-aerobic landfill
Leachate collection duct is bigger than the one of improved sanitary landfill. The opening of the duct is surrounded by air and the duct is covered with small crushed stones. Moisture content in solid waste is small. Oxygen is supplied to solid waste from leachate collection duct.
Aerobic landfill In addition to the leachate collection pipe, air supply pipes are attached and air is enforced to enter the solid waste of which condition becomes more aerobic than semi-aerobic landfill.
38
Figure 2.16: Classification of landfill structures (Chew, 2005)
CHAPTER 3
RESEARCH METHODOLOGY
3.1 Introduction
In this chapter, the methodology applied in order to carry out the tests and
analysis on the treatment of leachate using free water surface constructed wetlands
(FWSCW) is discussed. The pilot scale experiments on FWSCW treatment of
landfill leachate were conducted under ambient condition with an average
temperature of about 30˚C. Sanitary landfill leachate samples, collected from
Tanjung Langsat, Pasir Gudang municipal landfill site, located 42 km north-east of
Johor. This sanitary landfill began its operations in June 2002.
The experiments were conducted separately in the three (3) cells filled with
different leachate concentration where Cell A is 50% leachate concentration, Cell B
is 33% leachate concentration and Cell C act as control unit where there is no
Limnocharis flava was planted. Same number of wetland plants (60 no. of plants),
Limnocharis flava is placed in each of the two cells for leachate treatment. Sequence
of the experiment was conducted as shown in Appendix D. Figure 3.1 shows the
simplified research methodology.
40
Experimental Works
System 1
Cell A with 50% leachate
concentration and 40 no.m-2 to 60 no.m-2 of plant
System 2
Cell B with 33% leachate
concentration and 40 no.m-2 to 60 no.m-2 of plant
Experimental Set Up Set up of pilot scale constructed
wetlands
Sampling and Preservation
Data Analysis
• Based on the parameter observed in the experiment
• Removal efficiencies of pollutant
Conclusions and recommendation
Figure 3.1: The framework of study
41
3.2 Experimental Set Up and Operating Conditions of Constructed Wetland
Three pilot scale FWSCW units, made of reinforce concrete, were built at the
Environmental Laboratory, Faculty of Civil Engineering, Universiti Teknologi
Malaysia, each with a dimension of 0.5m x 4.0m x 0.5m (width x length x depth),
and a bed slope of 1% (Sawaittayothin and Chongrak, 2006) as shown in Plate 3.1.
The support media of these units consisted of large gravel (2 cm in diameter),
medium gravel (1 cm in diameter) and sand at depth 10 cm, respectively. Gravel was
selected because of its high hydraulic conductivity, ease of maintenance and
consistency of specification, allowing greater predictability of performance than
other soil media (Barr and Robinson, 1999).
Plate 3.1: Lab-scale constructed wetland
A species of wetland plant called Limnocharis flava (yellow burhead)
illustrated in Figure 3.2 has been chosen for various reasons. Firstly, it is one of the
most common wetland plants available in this region as it is also one of the wetland
plants in Putrajaya wetland (Lim et al, 1998). The plants were planted at a density of
60 no.m-2 for each unit. The campus domestic wastewater was fed continuously for
one week to the FWSCW units to acclimatize the soil microbes and to support
growth of the yellow burhead plant.
After the plants were fully grown to an average height of 3 cm, the FWSCW
units were continuously fed with the diluted landfill leachate for one week to let the
FWSCW units used to new condition. After that, the landfill leachate diluted with tap
water and fed into the FWSCW unit as shown in Plate 3.3 and 3.4 according to the
42
concentration chosen. The effects of different concentration on the treatment
performance of FWSCW were studied by varying the hydraulic retention time (HRT)
at 3, 6 and 9 day and the efficiencies of the system in terms of percentage removal of
the pollutant. Harvesting of the yellow burhead plants was conducted once every two
weeks by cutting the plant stems at about 30 cm above the FWSCW beds. About
50% of the burhead plants were harvested and 70% of the burhead plants were
planted each time to allow for the FWSCW beds to maintain treatment efficiencies.
The different concentrations of leachate are use for this study were Cell A is 50%
leachate and 50% tap water (1 leachate:1 water) and Cell B is 33% leachate and 67%
tap water (1 leachate:2 water).
All the physical, chemical and biological parameters of the wastewater were
analyzed according to the methods described in Standard Methods for the
examination of water and wastewater (APHA, 2002).
Yellow burhead belongs to Limnocharitaceae family. It is a perennial herb
that is native to tropical America and West Indies. This herb is a large hydrophyte
and can reach 70 cm in height. The leaves are rice paddle-shaped and soft. It blooms
yellow trefoil flowers on the trigonal floral axes. The young leaves and flowers are
used for a spicy herb or fodder in tropical areas. The characteristics of the
Limnocharis flava as stated in Table 3.1.
Figure 3.2: Limnocharis flava (yellow burhead)
43
Alternative Name(s): Yellow Burrhead. Family: Limnocharitaceae. Form: Water plant Origin: Native from Mexico to Paraguay and to the Caribbean Islands. Flowers/Seedhead: Flowers: At the end of long stems. Flowers recurving when fruiting and fruit buried in mud or water. Flowers year round. Description: Perennial herb to 1 m high and rooting in mud. Leaves broad-ovate, thick, 5–30 cm long, 4–25 cm wide, leaf stalk (petiole) 5–75 cm long, green. Fruit compound, to 2 cm wide, each fruit containing about 1,000 seeds. Seeds dark brown, horseshoe-shaped, to 1.5 mm long with obvious ridges.
Table 3.1: The characteristics of the Limnocharis flava
(Source: http://www.weeds.org.au/)
Plate 3.2: Dilution of landfill leachate before pour into the cells
44
50% 33% Plate 3.3: Different concentration of leachate used during
the experiment
3.3 Experimental Analysis
The entire tests were carried out in Environmental Laboratory, Faculty of
Civil Engineering, Universiti Teknologi Malaysia. The tests include parameter such
as Total suspended solid (TSS), turbidity, biochemical oxygen demand (COD), test
for nutrients such as nitrate, ammonia, phosphorus, manganese, and iron.
3.3.1 Analysis of Leachate
The leachate was sampled in each of two cells by using grab sampling
according to the standard methods (APHA, 2002). Sampling was done every 3, 6 and
9 days according to the HRT used and the analysis for each parameter was done in
Environmental Laboratory, Faculty of Civil Engineering, Universiti Teknologi
Malaysia, Skudai Johor. The parameter for leachate analysis was listed as follow:
45
(a) Turbidity
Turbidity test was conducted according to the Standard Method APHA by
using Spectrophotometer HACH DR 4000 Model, method used is 10047 (Attenuated
Radiation Method – Direct Reading) and Hach program is 3750.
(b) Biochemical Oxygen Demand
Biochemical Oxygen Demand (COD) test was conducted according to the
Standard Method APHA by using Spectrophotometer HACH DR 4000 Model,
method used is 8000 (Reactor Digestion Method) and Hach program is 2720.
(c) Ammonia Nitrogen
Ammonia Nitrogen (NH3-N) analysis was conducted according to Standard
Method APHA 4500-NH3-N by using Spectrophotometer HACH DR 4000 Model,
method used is 8038 (Nessler Method) and Hach program is 2400.
(d) Nitrate Nitrogen
Nitrate Nitrogen (NO3—N) analysis was conducted according to the Standard
Methods APHA 4500- NO3--N by using Spectrophotometer HACH DR 4000 Model,
method used is 8093 (Cadmium Reduction Method) and Hach program is 2530.
(e) Orthophosphate
Orthophosphate (PO43-) analysis was conducted according to the Standard
Methods APHA 4500-P (C) by Spectrophotometer HACH DR 4000 Model, method
used is 8048 (PhosVer 3 – Ascorbic Acid Method) and Hach program is 3025.
46
(f) Total Iron
Total iron was measured according to the Standard Methods APHA 3500-Fe
(B) by using Spectrophotometer HACH DR 4000 Model, method used is 8112
(TPTZ Method) and Hach program is 2190.
(g) Manganese (Mn)
Manganese was measured according to the Standard Methods APHA 3500-
Mn (B) by using Spectrophotometer HACH DR 4000 Model, method used is 8034
(Periodate Oxidation Method) and Hach program is 2250.
CHAPTER 4
RESULTS AND DISCUSSION
4.1 Introduction
In this chapter, the results from the laboratory analysis of the FWSCW will
be analyzed and discussed in details. The data will be shown in graphical approach to
evaluate the removal efficiency of the FWSCW system in treating landfill leachate.
The experimental studies were carried out for five months from May until
September. The effluent from the FWSCW was conclusively subdivided into three
categories, namely the physical parameters (TSS and Turbidity), nutrients (NH3-N,
NO3-N, P, Mn and Fe) and the organic matter (COD) The difference leachate
concentration was compared to evaluate the trends for the overall performance.
Analysis of variance (ANOVA) has been used to reveal significant
differences for all treatments. Statistical significance differences were tested at
p≤0.05 (95% levels of significance). Thus, an extensive discussion had been
concluded in the behavior obtained comparing significant differences between the
three tanks (control, 50% leachate concentration and 33% leachate concentration)
and comparing significant differences between HRT 3, 6 and 9 days.
48
4.2 Pollutant Removal in Leachate
The quality of the pre-treated leachate taken from the Tanjung Langsat
municipal landfill site, had characteristics as shown in Table 4.1. These data were
obtained from analyses of leachate samples collected six times during the study. The
quality of leachate, which is taken from the landfill, was found not to comply with
Standard B under Environmental Quality (Sewage and Industrial Effluent)
Regulations 1979 as shown in Appendix A.
Table 4.1: Characteristics of landfill leachate used in FWSCW experiments
Parameters Unit Range Average SD
COD mg/L 192-446 297.45 163.07
Orthophosphate mg/L 48.9-52.7 50.84 9.42
Nitrate-nitrogen mg/L 77.2-195 135.43 60.65
Ammonia-nitrogen mg/L 26.3-69.68 52.6 25.34
Manganese mg/L 0.66-2.0 1.16 0.78
Iron mg/L 0.02-0.42 0.55 0.72
Zinc mg/L 0.003-0.04 0.071 0.08
Chromium mg/L 0.02-0.08 0.16 0.15
Turbidity FAU 2-6 4.95 1.97
Suspended solid mg/L 2.5-7.5 1.53 0.70 SD = standard deviation; FAU = Formazin Attenuation Units
The quality of pre-treated landfill leachate after being 50% and 33% diluted
as shown in Table B1 (Appendix B) and the effluent quality after the leachate was
treated accordingly to the HRT by using the FWS constructed wetlands are
summarize in Table 4.2 and Table 4.3, while Table 4.4 shows the effluent quality for
the control unit. The percentages of removal for three (3) cells in terms of hydraulic
retention time (HRT) are depicted in Table 4.5, 4.6 and 4.7.
All the parameters are given in milligram per liter (mg/l) except for turbidity
given in FAU (Formazin Attenuation Units). A FAU is equivalent to a NTU
(Nephelometric Turbidity Units).
49
Table 4.2: Effluent concentration after treated by FWSCW for Cell A
Description Experimental unit HRT (day) (Cell A)
3 6 9 NH3-N (inf) 66.35 66.95 66.15 NH3-N (eff) 12.85 4.91 16.03 NO3-N (inf) 54.53 55.00 55.17 NO3-N (eff) 9.34 8.51 16.36 PO4
3- (inf) 4.38 4.95 3.69 PO4
3- (eff) 1.09 0.64 0.35 COD (inf) 279 289 248 COD (eff) 93 25 55 Mn (inf) 1.15 2.83 1.15 Mn (eff) 0.15 0.12 0.12 Zn (inf) 0.32 0.22 0.24 Zn (eff) 0.04 0.01 0.03 Fe (inf) 0.20 0.18 0.17 Fe (eff) 0.05 0.01 0.05 Turbidity (inf) 4.00 4.00 4.00 Turbidity (eff) 1.00 0.00 0.00 TSS (inf) 0.05 0.05 0.05 TSS (eff) 0.005 0.005 0
All units in mg/l, except for turbidity = FAU (Formazin Attenuation Units)
Table 4.3: Effluent concentration after treated by FWSCW for Cell B
Description Experimental unit HRT (day) (Cell B)
3 6 9 NH3-N (inf) 27.83 31.58 27.98 NH3-N (eff) 4.70 6.61 7.05 NO3-N (inf) 15.15 15.92 15.30 NO3-N (eff) 4.10 0.35 6.90 PO4
3- (inf) 3.16 2.92 3.31 PO4
3- (eff) 0.38 0.07 1.46 COD (inf) 265 296 266 COD (eff) 60 55 95 Mn (inf) 1.10 1.18 1.10 Mn (eff) 0.10 0.14 0.20 Zn (inf) 0.06 0.09 0.07 Zn (eff) 0.05 0.01 0.04 Fe (inf) 0.21 0.23 0.31 Fe (eff) 0.02 0.04 0.06 Turbidity (inf) 4.00 4.00 4.00 Turbidity (eff) 0.00 0.00 0.00 TSS (inf) 0.05 0.05 0.05 TSS (eff) 0.005 0.005 0
All units in mg/l, except for turbidity = FAU (Formazin Attenuation Units)
50
Table 4.4: Effluent concentration after treated by FWSCW for control unit
Description Experimental unit HRT (day) (control unit)
3 6 9 NH3-N (inf) 69.67 69.18 68.38 NH3-N (eff) 39.14 50.94 20.61 NO3-N (inf) 70.55 78.24 67.14 NO3-N (eff) 50.92 25.64 50.14 PO4
3- (inf) 53.80 48.43 55.25 PO4
3- (eff) 41.33 7.73 12.32 COD (inf) 403 461.5 400 COD (eff) 40.40 30.02 50.40 Mn (inf) 2.00 2.00 2.20 Mn (eff) 1.03 0.48 1.14 Zn (inf) 0.43 0.39 0.10 Zn (eff) 0.08 0.08 0.06 Fe (inf) 0.42 0.31 0.42 Fe (eff) 0.35 0.18 0.15 Turbidity (inf) 6.00 5.00 7.10 Turbidity (eff) 0.08 0.05 0.05 TSS (inf) 7.5 0.02 0.15 TSS (eff) 0.005 0 0
All units in mg/l, except for turbidity = FAU (Formazin Attenuation Units)
Table 4.5: Removal efficiencies in FWSCW at HRT 3 day
HRT = 3 day Description Cell A Cell B Control unit
NH3-N 80.63 % 83.11 % 43.82 % NO3-N 82.88 % 72.94 % 27.82 % PO4
3- 75.11 % 88.07 % 23.18 % COD 66.67 % 77.36 % 89.98 % Mn 86.96 % 90.91 % 48.50 % Zn 84.38 % 19.13 % 80.93 % Fe 74.87 % 91.71 % 16.67 % Turbidity 75 % 100 % 98.67 % TSS 90 % 90 % 99.93 %
51
Table 4.6: Removal efficiencies in FWSCW at HRT 6 day
HRT = 6 day Description Cell A Cell B Control unit NH3-N 92.67 % 79.07 % 26.36 % NO3-N 84.53 % 97.81 % 67.23 % PO4
3- 87.07 % 97.67 % 84.04 % COD 91.35 % 81.42 % 93.50 % Mn 89.57 % 88.14 % 76 % Zn 94.96 % 90.32 % 79.33 % Fe 94.44 % 83.04 % 41.29 % Turbidity 100 % 100 % 99 % TSS 90 % 9 % 100 %
Table 4.7: Removal efficiencies in FWSCW at HRT 9 day
HRT = 9 day Description Cell A Cell B Control unit NH3-N 75.76 % 74.80 % 69.86 % NO3-N 70.36 % 54.89 % 25.32 % PO4
3- 90.65 % 55.95 % 77.70 % COD 77.82 % 64.29 % 87.40 % Mn 89.57 % 81.82 % 48.18 % Zn 86.29 % 42.47 % 45.00 % Fe 69.64 % 79.34 % 63.33 % Turbidity 100 % 100 % 99.35 % TSS 100 % 100 % 100 %
4.3 Water Quality Analysis
There are several water quality parameters such as pH, alkalinity,
conductivity, dissolved oxygen, temperature, colour and etc. However, only two
water quality parameter that consider in this study, namely, total suspended solid
(TSS) and turbidity. Turbidity is a water quality parameter that refers to how clear
the water is. The greater the amount of total suspended solids (TSS) in the water, the
murkier it appears and the higher the measured turbidity. Analysis for both
parameters will be discussed in detailed in next sub-section.
52
4.3.1 Total Suspended Solid Removal
Suspended solids were identified as one of the contaminants of concern in
most landfill leachate effluent. Total suspended solids (TSS) include all particles
suspended in water that will not pass through a filter. Abundant suspended solids
such as clay and silt, fine particles of organic and inorganic matter (such as iron
particulate), soluble coloured compounds and phytoplankton can result in; decreased
light penetration in water reducing photosynthesis of water plants, decreased water
depth due to sediment build-up, the smothering of aquatic vegetation, habitat and
food, the smothering of macro and micro-organisms, larva, eggs and the clogging of
fish gills, the reduced efficiency of predation by visual hunters, and increased heat
absorbed by the water, lowering dissolved oxygen, facilitating parasite and disease
growth and increasing the toxicity of ammonia (Mason, 1998; and Boulton and
Brock, 1999).
Suspended solid removal in constructed wetlands is best facilitated through
the encouragement of settling. Effective settling in treatment wetland systems is most
commonly accommodated by the creation of a settling pond or a forebay at the head
of the wetland. They are typically designed to support long retention times in order to
allow the suspended solids and other debris to settle out. The increased depth
accommodates sediment build up, reducing the need for frequent dredging
(Tousignant et al., 1999).
On comparing the performance of different concentration, greater level of
TSS removal was observed in control unit at HRT 6 day was 100% removal, whereas
at HRT 9 day the greatest level of TSS removal occur in Cell A, B and control unit
with removal of 100% as shown in Figure 4.1. Roser et al. (1987) has reported that
the percentage removal of TSS for retention times 3-5 days is 89% compared to
retention times 6-9 days is 94%. It shows that the higher retention time, gives the
higher TSS removal. Other study performed by Gersberg et al. (1986), the removal
efficiencies for the vegetated beds were not significantly different from the
unvegetated bed. They concluded that the removal of SS was almost due entirely to
sedimentation and filtration rather than biological processes.
53
Moreover, the percentage of removal for those cells can reach up 100%
removal at HRT 9 days as shown Figure 4.1. The figure shows obviously increase in
TSS for control unit.
84
86
88
90
92
94
96
98
100TS
S re
mov
al (%
)
3 6 9HRT (days)
Control unitCell ACell B
Figure 4.1: Percentage of removal for Cell A and B for total suspended solids (TSS).
The FWSCW system can reach until 100% removal for both cells.
The TSS concentrations in those cells are shown in Figure 4.2 where the
concentration at HRT 6 and 9 day reaches 0 mg/l. According to Chongrak and Lim
(1998), settleable solids are removed easily via gravity sedimentation as wetland
systems generally have long hydraulic retention times (HRT). It was believed that all
the particles are trapped in the media. It shows that the media plays an important role
in terms of removal of suspended solid as well as to support the growth of rooted
emergent plant. According to Davit et al. (2001), solids are removed by physical
filtration and settling within the gravel/root hair matrix. Organic matter may also be
removed by these physical processes, but is ultimately removed through
biodegradation.
54
0.00000.00050.00100.00150.00200.00250.00300.00350.00400.00450.0050
TSS
conc
entra
tion
(mg/
l)
3 6 9HRT (days)
Control unitCell ACell B
Figure 4.2: Concentration of TSS as a function of sampling day for Cell A, B as well
as control unit where the concentration at HRT 9 day reaches 0 mg/l. It was believed
that all the particles are trapped in the media.
4.3.2 Turbidity Removal
Figure 4.3 illustrate the overall performance of turbidity removal for Cell A,
B and control unit free water surface constructed wetland systems in terms of
different hydraulic retention time (HRT).
0102030405060708090
100
Tubi
dity
rem
oval
(%)
3 6 9HRT (day)
Control unit
Cell A
Cell B
Figure 4.3: Percentage removal for Cell A, B and control unit in different HRT. The
percentage removals are increasing steadily where the system can reach until 100%
removal for those cells in FWSCW.
55
As TSS, similar trend was observed in turbidity removal. On comparing the
performance of different HRT, greater level of turbidity removal was observed at
HRT 6 and 9 day for Cell A, B and control unit as well where the removal are 100%,
100% and 99% respectively. While for HRT 3 day, the removal are 75%, 100% and
98.67% for Cell A, B and control unit.
0.000.100.200.300.400.500.600.700.800.901.00
Turb
idity
con
cent
ratio
n (F
AU
)
3 6 9HRT (day)
Control unitCell ACell B
Figure 4.4: The turbidity concentration with different HRT for Cell A, B and control
unit where the leachate concentration are decrease due to sedimentation and filtration
that occur during the process.
Figure 4.4 shows the reduction of turbidity up to 0 FAU due to sedimentation
and filtration. However, at HRT 3 d, turbidity removal for Cell A is 1 FAU but others
is less than 0.1 FAU. Typically, a biological process associated with the plants was
not contributed to turbidity removal since the percentage between both
concentrations was not significantly different (Nazaitulshila, 2006).
Results are given in FAU (Formazin Attenuation Units) not Nephelometric
Turbidity Units (NTU). A FAU is equivalent to a NTU.
56
4.4 Organic Matter Analysis
4.4.1 Biochemical Oxygen Demand Removal
For this research, the biodegradable organic matter being studied in landfill
leachate is Chemical Oxygen Demand (COD). In wetland systems, microbial
degradation plays a dominant role in the removal of soluble/colloidal biodegradable
organic matter (BOD or COD) in wastewater, the remaining BOD associated with
settleable solids being removed by sedimentation (Chongrak and Lim, 1998).
However, the BOD test is neglect in this study due to shortage of time and
equipment.
Figure 4.5 showed the COD removal efficiency in control experiment and
different leachate concentration with different HRT wetlands with exposure to
natural environmental condition.
010
2030
40
5060
70
8090
100
COD
rem
oval
(%)
3 6 9HRT (day)
Control UnitCell ACell B
Figure 4.5: The percentage of removal of COD for Cell A, B and control unit. The
removals are increase steadily up to 94% removal in control unit. On the other hand,
the removal of control unit higher than Cell A and B which was probably due to the
presence of non-biodegradable organic compounds in the landfill leachate.
The treatment performance of the three (3) units operating at the various HRT
is shown in Table 4.2 through 4.7. At steady state conditions, the FWSCW units
operating at HRT of 6 day had more than 80% of organic (COD) removal for Cell A,
57
B and control unit with the effluent COD concentrations being less than 100 mg/L as
shown in Figure 4.6 which is comply with Standard B under Environmental Quality
(Sewage and Industrial Effluent) Regulations 1979. COD is used to evaluate the
organic strength of domestic and industrial wastewaster (Pouliot, 1999). It measures
the amount of oxygen necessary to complete oxidize all organic matter. The
percentages of COD removal in the experimental FWSCW unit of Cell A (50%
concentration) and Cell B (33% concentration) are slightly higher than those control
unit which was probably due to the presence of non-biodegradable organic
compounds in the landfill leachate.
40
93
60
3025
55.00 50.4055
95.00
0102030405060708090
100
CO
D c
once
ntra
tion
(mg/
l)
3 6 9HRT (day)
Control unitCell ACell B
Figure 4.6: The effluent quality for Cell A, B and control unit with different HRT.
The highest COD removal occurs in Cell B at HRT 9 day with 95.0 mg/l. The
effluent quality for HRT 3 day can be observed in Cell A with 93.0 mg/l.
Chemical oxygen demand (COD) is a measure of the amount of the oxygen
required to chemically oxidize reduced minerals and organic matter. It does not
differentiate between biologically available and inert organic matter (Galbrand,
2003). In general, the greater the COD value in water, the more oxygen influent
demands, from the water body, thus resulting in depleted dissolved oxygen which is
essential to the metabolisme of all aerobic aquatic organisme (Silva et. al., 2003;
Cusso et. al., 2001).
According to Crites and Tchobanoglous (1998), the COD removal in control
unit increased due to the algae decay that released and recycled back the organic and
inorganic matter in the leachate. Thus, the COD in the control unit did not decrease
58
but increased throughout the experiment as illustrated in Figure 4.5. As reported by
Wood et al. (1989), the poor COD removal efficiency was due to the high surface
loading rate and incapacity of the macrophytes to meet the oxygen demand.
4.5 Chemical Water Quality Analysis
4.5.1 Ammonia Nitrogen Removal
Ammonia was identified as one of the contaminants of concern in most
landfill leachate effluent. Ammonia nitrogen is a pungent, gaseous compound of
nitrogen and hydrogen and includes both ammonia (NH3) and ammonium ion (NH4-).
More common in landfill leachate is the ionized form NH4+ which is formed when
NH3 is combined with water at pH less than 8.5 and low temperatures to produce an
ammonium ion and a hydroxide ion (OH-) (Galbrand, 2003). Ammonia
concentrations are typically less than 0.1 mg/l in natural waters.
Figure 4.7 depicted the NH3-N removal efficiency of Cell A, B and control
unit under different hydraulic retention time (HRT) with exposure to natural
environmental condition.
43.82
80.6383.11
26.36
92.67
79.07
69.8675.7674.80
0
10
20
30
40
50
60
70
80
90
100
Am
mon
ia n
itrog
en re
mov
al
(%)
3 6 9HRT (day)
Control Unit
Cell A
Cell B
Figure 4.7: The percentage of removal for NH3-N with different hydraulic retention
time (HRT). The highest removal can be obtained in Cell A at HRT 6 day. The
lowest removal of NH3-N occurs in control unit with 26% at HRT 6 day.
59
Removal of ammonia nitrogen (NH3-N) was the highest in Cell A under three
different HRT which is 81% removal at HRT 3 day, 93% removal at HRT 6 day and
76% removal at HRT 9 day. An overall, the lowest removal can be obtained at HRT
9 day where the removals are 70% removal in control unit, 76% removal in Cell A
and 75% removal in Cell B due to the plant wilting. As reported by El-Gendy (2003),
plant wilting will increase the nutrient concentration in leachate which included NH3-
N.
Figure 4.7 indicated the significance of HRT on treatment performance of
FWSCW. The HRT 3 and 9 day were found to be too short and too long for the
FWSCW units to effectively treat the landfill leachate. According to Chongrak and
Lim (1998), the HRT is one of the major factors affecting the treatment performance.
In general, a too long HRT can result in stagnant anaerobic conditions whereas the
shorter HRT do not provide sufficient time for degradation of pollutants. However,
the best performance of NH3-N can be obtained at HRT 6 day.
Plant uptake for NH3-N was not significant in the wetlands since the NH3-N
removal efficiency in control unit is nearly to removal efficiency in Cell A and B.
Thus, most of the NH3-N removal mechanisms involved in nitrification by
Nitrosomonas and Nitrobacter bacteria (Boulton and Brock, 1999). However, the
plants provided aerobic zone in the root for nitrification to be occurred as reported by
Chongrak and Lim (1998).
4.5.2 Nitrate Nitrogen Removal
In aerobic conditions, nitrite is typically rapidly oxidized to nitrate by
Nitrobacter bacteria. Nitrate is an inorganic compound of nitrogen which is
bioavailable for plant uptake and is essential to plant growth (Boulton and Brock,
1999; Freedman, 2001). Natural levels of nitrate in waterbodies are typically lower
than 1 mg/l where nitrite and ammonia are toxic, nitrate is virtually harmless, with
direct toxic effect typically not observed until concentrations greater than 1000 mg/l
(Mason, 1998). However, if phosphorus concentrations are sufficient, high nitrate
60
content in waters can increase the severity of eutrophication, which can have chronic
effects of aquatic life.
In this study, only ammonia nitrogen (NH3-N) and nitrate (NO3-N) will be
considered, the others are possible due to their transformation are to short and the
limitation of the laboratory apparatus. Nitrification is usually defined as the
biological oxidation of ammonium to nitrate with nitirite as an intermediate in the
reaction sequence. The nitrate nitrogen (NO3-N) removal in the FWSCW unit ranged
from 28% to 83% for HRT 3 day, 67% to 98% for HRT 6 day and 25% to 70% for
HRT 9 day. The laboratory analyses for the effluent of the FWSCW are shown in
Figure 4.8.
27.82
82.8872.94
67.23
84.5397.81
25.32
70.36
54.89
0102030405060708090
100
Nitr
ate-
nitro
gen
rem
oval
(%)
3 6 9HRT (day)
Control UnitCell ACell B
Figure 4.8: The percentage of removal for NO3-N with different hydraulic retention
time (HRT). The highest removal can be obtained in Cell B at HRT 6 day with
removal 98%. The lowest removal of NO3-N occurs in control unit with 25% at HRT
9 day.
Figure 4.8 indicates the overall performance of NO3-N removal efficiency of
three different hydraulic retention times (HRTs) in FWSCW with expose to natural
environmental condition.
NO3-N removal in control unit is slightly lower due to unvegetated beds. In
comparison among three cells, Cell B was the most efficient in removing NO3-N
which was 98%. On the other hand, the best HRT for NO3-N removal is HRT 6 day
where 67% removal achieved in control unit instead of 28% and 25% at HRT 3 and 9
61
days, 85% NO3-N removal can be obtained in Cell A (HRT = 6 day) instead of 83%
and 79% in HRT3 and 9 days, and the highest removal occurred in Cell B with 98%
removal instead of 73% and 55% at HRT 3 and 9 days. As a conclusion, the best
HRT in terms of NO3-N removal is HRT 6.
According to Gersberg et al. (1983), the plant uptake was not a significant
pathway in the overall nitrogen removal and that the major loss of nitrogen from the
system was due to denitrification. Moreover, Gersberg et al. (1986) investigated the
wetland beds planted achieved ammoniacal nitrogen efficiencies of 94% as
compared with only 11% for unvegetated beds at the HLR of 4.7cm/d or HRT of 6
days. Research performed by Roser et al. (1987), both planted and unplanted gravel
beds yielded similar percentages of N removal. Average percentage of N removal
was about 51% for HRT of 3-5 day and 54% for HRT of 6-9 days.
NO3-N removal was lower in Cell A than Cell B due to the plant wilting that
eventually increased NO3-N concentration in the leachate (Crites and
Tchobanoglous, 1998). As stated by Nivala et al. (2006), low concentration of
effluent NO3-N can mean one of two thing; (Case I) that nitrification is not occurring
and NO3-N is not being formed (corresponding to minimal net removal of nitrogen),
or (Case II) that both nitrification and denitrification processes are occurring to
completion (corresponding to high net removal of nitrogen).
4.5.3 Orthophosphate Removal
Phosphorus in wetland occurs as phosphate in organic and inorganic
compounds. Free orthophosphate is the only form of phosphorus believed to be
utilized directly by algae and macrophytes and thus represents a major link between
organic and inorganic phosphorus cycling in wetlands. Moreover, according to Lee
and Jones-Lee (2001), the phosphorus is an essential macronutrient that is a limiting
factor to plant growth. It is essential to all life as a component of nucleic acids and a
universal energy molecule. In excess, phosphorus triggers eutrophic conditions
which involve the profilic growth of algal and other aquatic plants. Algal growth can
62
have lethal impacts on aquatic life and, at high concentrations, can be toxic in itself
(Galbrand, 2003).
Figure 4.9 indicates the PO43- removal efficiency under different hydraulic
retention time (HRTs) in FWSCW with expose to natural environmental condition.
23.18
75.11
88.0784.04
87.0797.67
77.70
90.65
55.95
0102030405060708090
100
Ortg
opho
spha
te re
mov
al (%
)
3 6 9HRT (day)
Control UnitCell ACell B
Figure 4.9: The percentage removal of orthophosphate under different HRT. The
highest removal can be obtained in Cell B at HRT 6 day with removal 98%. The
lowest removal of PO43- occurs in control unit with 23% at HRT 3 day.
PO43- removal efficiency was low in the control unit at HRT 3 day and HRT
9 days with removal of 56% in Cell B. According to Chongrak and Lim (1998), the
low removal efficiency was due to the reason that the plant uptake and
microoganisms biodegradation were not the major mechanisms in PO43- removal.
Instead, adsorption and precipitation was the major removal pathway where
phosphorus was adsorbed to the soils or precipitated with calcium/aluminium
(Kadlec and Knight, 1996; Boulton and Brock, 1999).
The highest removal efficiency can be obtained at HRT 6 days where Cell A
is 87% removal, Cell B is 98% removal and control unit is 84% removal. Research
performed by Roser et al. (1987), both planted and unplanted gravel beds yielded
similar percentages of P removal. The authors suggested that filtration was a
significant P removal mechanism as shown by the ability of the unplanted bed to
match the P removal efficiency achieved by the planted systems.
63
It shows not much different due to the settlement of the nutrient at the surface
of the soil media. As revealed by Rosolen (2000), the phosphorus absorbed onto
suspended sediments will be filtered out as the suspended solids are removed.
Phosphorus has very low solubility, and is readily moved from solution by several
precipitation and adsorption reactions by binding it in an insoluble form. Kim and
Geary (2000) reported that soil substrates are the ultimate sink for phosphorus.
The absorption of sunlight by algal blooms reduces amount of light reaching
aquatic plants in sediments. If an algal bloom is prolonged, aquatic plants will die.
Large amounts of decaying algae result in the consummation of large quantities of
oxygen by the bacteria and fungi that break it down. This results in the dramatic
reduction of oxygen concentrations in the water column, particularly at night. This
reduction affects invertebrate predators with high oxygen requirements. The
subsequent lack of predators results in critical disruptions in food chain and increases
of nuisance species such as mosquitoes. Algal blooms can also contain toxic strains
of blue-green algae which may kill birds, domestic animals, aquatic
macroinvertebrates and even humans if consumed (Lee and Jones-Lee, 2001;
Sharpley et. al., 1994).
4.5.4 Manganese Removal
Manganese was also identified as one of the contaminants of concern in the
landfill leachate effluent needing treatment. Manganese (Mn) is a transition metal
which is grey, white of silver in colour. It is soft and ductile if pure but usually
occurs in compounds and complexes with organic compounds (Sample et. al., 1997).
Zhu et al., (1997) declared that a metal such as Fe and Mn correlates to the ability of
a particle to remove phosphorus. Adsorption is dependent on composition of the
material, which is oxides of these metals, while the availability of these minerals in
the soluble form will direct precipitation reactions.
Manganese is an essential micronutrient forming a vital part of the enzyme
systems that metabolise proteins and energy in all animals (Galbrand, 2003). There
64
are about eight nutrients essential to plant growth and health that are only needed in
very small quantities. These are manganese, boron, copper, iron, chlorine, cobalt,
molybdenum, and zinc. Though these are present in only small quantities, they are all
necessary.
Figure 4.10 indicates the Mn removal efficiency for Cell A, B and control
unit under different hydraulic retention time (HRT) with exposure to natural
environmental condition.
48.50
86.96 90.91
76.00
89.57 88.14
48.18
89.5781.82
0102030405060708090
100
Man
gane
se re
mov
al (%
)
3 6 9HRT (days)
Control unitCell ACell B
Figure 4.10: The percentage removal of manganese under different HRT. The
highest removal can be obtained in Cell B at HRT 3 day with removal 91%. The
lowest removal of Mn occurs in control unit with 48% at HRT 9 day.
Different HRT that use in the FWSCW gives not much different in remove
manganese (Mn). At HRT 3 days 87% removal in Cell A, 91% removal in Cell B,
and 49% removal in control unit. Therefore, at HRT 6 days, 90% removal occurred
in Cell A, 88% removal in Cell B and 76% removal in control unit. The longer HRT
in this experiment is 9 days where 90% removal in Cell A, 82% in Cell B, and 48%
removal in control unit.
Mn uptake by plants Limnocharis flava was less than Fe. According to Kamal
et al. (2004), F2+ was the micronutrient for plants that was required in higher
concentration than Mn2+. Mn removal was slightly higher at HRT 3 days. This was
due to the plant wilting that minimized plant uptake for Mn (Soltan and Rashed,
2003).
65
4.5.5 Iron Removal
The iron (Fe) removal efficiency was observed in the study as shown in
Figure 4.11. The percentages of removal for three cells are fluctuating. At HRT 6
days, the iron (Fe) concentrations are increased due to the accumulation of the iron in
the media bed. Iron (Fe) removal in the FWSCW was rather effective, where the
94% removal in Cell A and 83% in Cell B at HRT 6 days. Also, over the course of
sampling, the iron concentration at HRT 9 days fluctuated drastically than HRT 3
and 6 days, decreasing throughout the rainy days. Rain likely brought more iron into
the treatment wetland. The lowest percentage removal of manganese can be obtained
at HRT 9 days where 70% removal in Cell A, 79% removal in Cell B and 63%
removal in control unit.
16.67
74.87
91.71
41.29
94.44
83.04
63.3369.64
79.34
0102030405060708090
100
Iron
rem
oval
(%)
3 6 9HRT (day)
Control unitCell ACell B
Figure 4.11: The percentage removal of iron (Fe) under different HRT. The highest
removal can be obtained in Cell A at HRT 6 days with removal 94%. The lowest
removal of Mn occurs in control unit with 17% at HRT 3 days.
As reported by King et al. (1992), Fe is an essential micronutrient element
required by both plants and wildlife at significant concentrations. The results of
vegetated treatment system described that the Limnocharis flava as an emergent
plants play a crucial part in the treatment systems. Emergent plants help in reducing
heavy metals by retaining it either in the root of in the leaves. Capacity in
accumulating and removing heavy metals are varied according to plant species.
Uptake and accumulation of elements by plants may follow two different paths
66
which were n root system and foliar surface (Sawidis, et al., 2001). Nevertheless, the
result also indicated that the capability of hydraulic retention time (HRT) in FWSCW
those systems assist Fe removal.
4.6 Analysis of Variance
Analysis of variance (ANOVA) has been used to reveal significant
differences for all types of treatment systems. Statistical significance differences
were tested at p≤0.05 (95% levels of significance). Table 4.8 through 4.10 shows the
p value when comparing significant differences between control, 50% leachate
concentration and 33% leachate concentration and different HRT used in the
FWSCW to treat landfill leachate.
The details calculation of ANOVA for HRT 3, 6 and 9 day as presented in
Table C1 until C24 in Appendix C.
Table 4.8: Significant differences between control, Cell A and Cell B at HRT 3 days
ANOVA Two Factor Without Replication 95% levels of significance
p value p value Parameters Significant
p ≥ 0.05 Significant
p ≤ 0.05 TSS 0.244 Turbidity 0.571 NH3
-N 0.00315 NO3
-N 7.31E-05 PO4
3- 1.69E-05 COD 0.00089 Fe 0.0682 Mn 0.000205
67
Table 4.9: Significant differences between control, Cell A and Cell B at HRT 6 days
ANOVA Two Factor Without Replication 95% levels of significance
p value p value Parameters Significant
p ≥ 0.05 Significant
p ≤ 0.05 TSS 0.7164 Turbidity 0.00768 NH3
-N 9.53E-05 NO3
-N 0.00189 PO4
3- 0.3705 COD 0.124 Fe 0.0572 Mn 0.00133
Table 4.10: Significant differences between control, Cell A and Cell B at HRT 9
days
ANOVA Two Factor Without Replication 95% levels of significance
p value p value Parameters Significant
p ≥ 0.05 Significant
p ≤ 0.05 TSS 0.1296 Turbidity 0.5274 NH3
-N 0.0045 NO3
-N 0.000157 PO4
3- 0.5102 COD 0.2710 Fe 0.00727 Mn 0.9816
4.7 Conclusion
From the results and analysis, the constructed wetland vegetated with
Limnocharis flava have shown their ability to remove suspended solid (TSS),
turbidity, nitrate (NO3-N), phosphorus (P), ammoniacal nitrogen (NH4
-N), ferum (Fe)
and manganese (Mn) from leachate. The leachate concentration used in this
experiment was 50% (Cell A), 33% (Cell B) and 100% (control unit). Study done by
Hui (2005) had revealed that 50% leachate concentration will give the highest
removal efficiency in removing NO3-N and Mn.
68
The different hydraulic retention time (HRT) also affects the pollutant
removal in the FWSCW. An overall, the hydraulic retention time of 6 days shows the
greater removal in all parameters except for manganese.
On comparing between control unit and Cell A and B, Cell A and B gives the
highest removal especially at HRT 6 days as shown in Table 4.11. However, both
cells show the removal more than 80%.
Table 4.11: Percentage removal for three cells at HRT 6 days
Description HRT = 6 day Cell A Cell B Control unit NH3-N (%) 92.67 79.07 26.36 NO3-N (%) 84.53 97.81 67.23 PO4
3- (%) 87.07 97.67 84.04 COD (%) 91.35 81.42 93.50 Mn (%) 89.57 88.14 76.00 Zn (%) 94.96 90.32 79.33 Fe (%) 94.44 83.04 41.29 Turbidity (%) 100.00 100.00 99.00 TSS (%) 90.00 90.00 100.00
In a constructed wetland systems, the HRT is one of the major factors
affecting the treatment performance. In general, a too long HRT can result in
stagnant anaerobic conditions whereas shorther HRTs do not provide sufficient time
for the degradation of pollutants.
CHAPTER 5
CONCLUSIONS
5.1 Introduction
Wetlands are, as the word indicates, wet lands, with soils that are morw or
less water saturated, at least periodically. The plants growing in wetlands (often
called wetlands plants or macrophyte) are adapted to growing in water saturated soils
(Brix, 1994).
The quality of landfill leachate is highly dependent upon the stage of
fermentation (age of landfill), waste decomposition, operational procedures and co-
disposal of industrial wastes.
Lab-scale free water surface constructed wetland systems, employing natural
soil and the yellow burhead (Limnocharis flava), were used to evaluate the landfill
leachate effluent. Several aspects were investigated during this experiment; water
quality parameters (TSS and turbidity) were monitored, and pollutant (NH3, NO3, P,
Fe, and Mn) removal efficiencies were evaluated.
The wetland system was proven effective in pollutants removal in leachate.
Wetland of 33% leachate concentration showed high removal efficiency especially at
70
hydraulic retention time (HRT) 6 days. During the experiment, there about 50% of
the Limnocharic flava were harvest and about 70% of Limnocharis flava were
planted each time to allow for the FWSCW beds to maintain treatment efficiencies.
According to Mbuligwe (2005), the plant harvesting could be done in the wetland to
promote active growth of the plants, avoid mosquito proliferation and to improve the
efficiency of the treatment performance.
In this study, the different HRT are used to evaluate the efficiencies of
FWSCW in removal of pollutants with different leachate concentration. However,
the laboratory results shows that the removal efficiencies for 50% leachate
concentration and 33% leaachate concentration not much different. Both cells shows
the removal more than 80% pollutant removal.
The FWSCW were effective in treating the leachate wastewater, resulting in a
treated effluent suitable for reuse in agriculture or discharge to nearby environment
since the the effluent from FWSCW does not exceed the limit of Standard B
Environmental Quality Act.
Better removal efficiencies were obtained for all parameters in Cell B (33%
leachate concentration) especially at HRT 6 days. Therefore, the FWSCW system is
suitable for tertiary landfill leachate treatment. It could be concluded that higher
leachate concentration was more efficient in removing pollutants from leachate due
to the presence of microorganisms for biodegaradation (Stottmeister et al., 2003).
5.2 Recommendations
For future research, there are more extensive studies could be carried out in
order to understand more clearly the processes/mechanisms that happen in
constructed wetland. There are some recommendations for future research:
71
i) A better understanding of the nitrogen removal and nitrogen
transformations occurring in free water surface flow constructed wetlands
systems is necessary and this could ensure a better removal of ammonia
nitrogen and nitrate in the system.
ii) A better understanding and control of the incoming raw landfill leachate
is necessary and this could give useful information during operating the
system.
iii) Use other types of plant such as reeds and bulrushes to determine the
performance and removal efficiency of the constructed wetlands systems.
iv) The use of specialized media other than the media in this study to
improved the porosity and penetration of plant root and avoids clogging
from occurring.
v) Longer period of the test is necessary to determine the fullest capacity of
the free water surface flow constructed wetlands in terms of pollutant
removal.
5.3 Conclusions
Constructed wetlands are getting much attention nowadays as their potential
to provide an effective, low-cost, natural method of removing pollutants from
wastewater are recognized. Biotic component of wetlands especially the vegetation
affects water conditions through many mechanisms physically, chemically and
biologically. There are many unpredictable long-range effects that may develop as
constructed wetlands evolved.
Removal efficiency of the FWSCW in this study did show an effective
performance as predicted. Presence of Limnocharis flava and the second cultivation
of the selected plant did increase the ability of the free water surface flow
72
constructed wetlands to decrease the level of organic matters and increase removal of
nutrients as the analyses was made.
Analysis of variance (ANOVA) has been used to reveal significant
differences for all types of treatment systems. Statistical significance differences
were tested at p≤0.05 (95% levels of significance). The p value are observed when
comparing significant differences between control, 50% leachate concentration and
33% leachate concentration and different HRT used in the FWSCW to treat landfill
leachate.
REFERENCE
Amokrane, A., Comel, C., and Veron, J. (1997), Landfill leachate pretreatment by
coagulation-flocculation. Water Res. 31, 2775-2782.
APHA (2002), Standard methods for Examination of Water and Wastewater. 21th
edition. Washington: American Public Health Association.
Ayob, K. and Supiah, S. (2005). Watershed Protection: A Key Factor Towards
Sustainable Reservoir Yield. Journal The Ingenieur, Board of Engineer.
Barr, M. J. and Robinson, H. D. Constructed Wetlands for Landfill Leachate
Treatment. Waste Management & Research, Vol. 17, No. 6, 498-504 (1999),
International Solid Waste Association. Aspinwall and Company. 1999.
Bastian, R. K., Shanaghan, P. E. and Thompson, B. P. (1989). Use of Wetlands For
Municipal Wastewater treatment And Disposal – regulatory issues and EPA
policies. In Hammer, D. A. (ed.). Constructed Wetlands for Wastewater
Treatment: Municipal, Inductrial, and Agricultural. Chelsea: Lewis Publishers.
Blakey, N.C. (1992). Model prediction of landfill leachate production. In:
Christensen, T.H., Cossu, R., Stegmann, R., Ed. Landfilling of Waste: Leachate.
London and New York: Elsevier Applied Science. 17-34.
Boulton, A. J. and Brock, M. A. (1999). Australian Freshwater Ecology: process and
Management. Cooperative Research Centre for Freshwater Ecology and
Gleneagles Publishing: SA.
Boyle, W. C. and Ham, R. K. (1974). Biological Treatability Of Landfil Leachate.
Journal Water Pollutiom Control Federation. 46(5): 860-872.
Brix, H. (1993). Macrophyte-mediated Oxygen Transfer in Wetlands: Transport
Mechanisms and Rate. In Moshiri, G. A. (Ed.). Constructed Wetlands For Water
Quality Improvement. (pp 391-398). Boca Raton, Florida: Lewis Publishers.
74
Brix, and Hans (1994). Functions of Macrophytes in Constructed Wetlands. Wat. Sci.
Tech. 29 (4): 71-78.
Chew Ai Ling (2006). Nutrient Removal From Leachate Using Horizontal
Subsurface Constructed Wetlands. Universiti Teknologi Malaysia: MSc. Thesis.
Chritensen, T. H., Cossu, R. and Stegmann, R. (1992). Landfilling of Waste:
Leachate. England: Elsevier Science Publishers Ltd.
Chongrak, P. and Lim, P. E., (1998). Constructed Wetland For Wastewater
Treatment and Resource Recovery. Thailand: Environmental Systems
Information Center.
Davis, L. (1995). A Handbook Of Constructed Wetlands: A Guide to Creating
Wetlands for Agriculture Waste, Domestic Wastewater, Coal Mine Drainage And
Stormwater In The Mid-Atlantic Region. Volume I: General Considerations.
Washingto DC: Natural Resources Conservation Service, US Environmental
Protection Agency-Region III and the Pennsylvania Department of
Environmental Resources.
DeBusk, Thomas A. et al. (2001). Wetlands for Water Treatment – Applied Wetlands
Science and Technology. Boca Rato: CRC Press LLC.
Cooper, P. F. (1999). A Review of A Design and Performance Of Vertical Flow and
Hybrid Reed Bed Treatment Systems. Water Science technology. 40(3): 1-9.
Cooper, P. F., Findlater, B. C., (eds). (1990). Constructed Wetands in Water
pollution Control. New York: Pergamon Press.
Cooper, P. F. (2001). Nitrificatiion and Denitrification In Hybrid Constructed
Wetlands Systems. In: Vymal, J. (eds.), Transformations On Nutrients In Natural
and Constructed Wetlands. (pp 257-270). The Netherlands: Backhuys Publishers.
Sawaittayothin, V. and Chongrak, P. (2006). Nitrogen Mass Balance and Microbial
Analysis of Constructed Wetlands Treating Municipal Landfill Leachate.
Bioresource Technology. 98(2007): 565-570.
Cook, C.D.K. (1996). Aquatic Plant Book. The Hague: SPB Academic
Publishing/Backhuys Publishers. Pg 228.
Cronk, K. J. and Fennessy, M. S. (2001). Wetland Plants Biology and Ecology. Boca
Raton, Florida, United State of America: Lewis Publisher.
Cusso, R., Haarstad, K., Lavagnolo, M. C. and Littarru, P. (2001). Removal of
Municipal Solid Waste COD and NH4-N Byphyto-Reduction: A Laboratory-
75
Scale Comparison of Terrestrial and Aquatic Species at Different Organic Loads.
Chemosphere. 16:459-470.
David, M. G., James, L. A., Christopherson, S. H., Rich, A. (2001). Constructed
Wetlands. Innovative Onsite Sewage Treatment Systems. Communication and
Educational Technology Services, University of Minnesota Extension.
Davies, T. H. and Hart, B. T. (1990). Use of aeration To Promote Nitrification In
Reed Beds Treating Wastewater. Advance Water Pollution Control. 11:77-84.
Dunbabin, J. S. and Bowmer, K. H. (1992). Potential Use of Constructed Wetlands
for Treatment of Industrial Wastewaters Cointaining Metals. The Science of The
Total Environment. 2-3:151-168.
El-Fadel, M., Findikakis, A. N. And Leckie, J. O. (1997). Environmental Impacts of
Solid Waste Landfilling. Journal of Environmental Management. 50: 1-25.
Eyles, N. and Boyce, J. J. (1997). Geology and Urban Waste Management in
Southern Ontario. In: Eyles, N. ed. Environmental Geology of Urban Areas.
Canada: Geological Association of Canada. 297-322.
Fennessy, S. and Mitsch, W. J. (1992). Design and Use of Wetlands for Renovation
of Dainage from Coal Mines. In: Jorgensen, S. E. and Mitsch. W. J. (ed.).
Ecological Engineering: An Introduction To Ecotechnology. New York: Van
Nostrand Reinhold.
Field, S (1993). Regulations and Policies Relating To The Use Of Wetlands For
Nonpoint Source Pollution Control. In: Olson, R. K. ed. Created and Wetlands
For Controlling Nonpoint Source Pollution. CRC Press: Boca Raton, Florida.
151-158.
Forsburg, Jennifer C. (1996) Evaluation of Subsurface Flow Constructed Wetlands
for the Treatment of Heavy Metals in Municipal Solid Waste Landfill Leachate.
State University of New York: MSc. Thesis.
Freedman, B. (2001). Agriculture and Environment. In: Freedman, B. Environmental
Science: A Canadian Perspective. 2nd Edition. Toronto, ON: Pearson Education
Canada Inc.
Galbrand Catherine C. (2003). Naturalized Treatment Wetlands for Contaminant
Removal: A Case Study of The Burnside Engineered Wetland for Treatment of
Landfill Leachate. Dalhousie University: MSc. Thesis.
Gersberg, R. M., Elkins, B. V. and Goldman, C. R. (1983). Nitrogen Removal In
Artificial Wetlands. Water Research 17(9):1009-1014.
76
Gersberg, R. M., Elkins, B. V., Lyon, S. R. and Goldman, C. R. (1986). Role of
Aquatic Plants In Wastewater Treatment B Artifial Wetlands. Water Research
20(3):363-368.
Hagedorn, C., McCoy, E. L., and Rabe, T. M. (1981). The Potential for Groung
Water Contamination from Septic Effluents. Environmental Quality. 10(1).
Hauck, R. D. (1984). Atmospheric Nitrogen Chemistry, Nitrification, Denitrification,
And Their Relationships. In: Hutzinger O. (eds). The Handbook of
Environmental Chemistry. Vol. 1. Part C, The Natural Environment And
Biogeochemical Cycles. (pp 105-27) Berlin: Springer-Verlag.
Hammer, D. A. and Knight, R. L. (1994). Designing Constructed Wetlands for
Nitrogen Removal. In: Amah, G.I. Constructed Treatment Wetlands for Reducing
Nutrient Loading in the Lower MalibuCreek Watershed. US: University of
California.
Harrington, D.W., Maris, J.P. (1986) The treatment of leachate: a UK perspective.
Water Pollutant Control. pp 45-56.
Haslam, S. M., (1978). River Plants: The Macrophytic Vegetation of Watercourses.
Cambridge. Cambridge University Press. pp 396.
Henry, J.G., Prasad, D., and Young, H. (1987) Removal of organics from leachate by
anaerobic filter. Water Res. 21, 1395-1399.
House, C. H. Bergmann, B. A., Stomp, A. M., and Frederick, D. J. (1999).
Combining Constructd Wetlands and Aquatic and Soil Filters for Reclamation
and Reuse of Water. Ecological Engineering. 12 (27).
Howard, K. W. F. Impact of Urban Development on Ground Water. In: Eyles, N. ed.
Environmental Geology of Urban Areas. Canada: Geological Association of
Canada. 104-116; 1997.
Jetten, M. S. M., Logemann, S., Muyzer, G. M., Robertson L. A., DeVries, S., and
Loosdrecht, V. M. C. M. (1997). Novel Principles In The Microbial Conversion
Of Nitrogen Compounds. Antonie van Leeuwenhoek.
Kamal, M., Ghaly, A. E., Mahmoud, N. and Côté, R. (2004). Phytoaccumulation of
Heavy Metals by Aquatic Plants. Environment International. 29: 1029-1039.
King, B. R., Long, G. M. and Sheldon, J. K. (1992). Practical Environmental
Bioremediation. Boca Raton, Florida: Lewis Publisher.
77
Lee, G. F. and Jones-Lee, A. (2001). Assessing the Water Quality Impacts of
Phosphrus in Runoff from Agricultural Land. Proceedings of American Chemical
Society Agro Division Symposium: Environmental Impacts of Fertilizer Products
in Soil, Air and Water. Chicago, IL: American Chemical Society.
Liehr, S., Kozub, D., Rash, J., Sloop, M., Doll, B., Rubin, R., House, H., Hawes, S.
and Burks, D. (2000). Constructed Wetlands Treatment of High Nitrogen
Landfill Leachate. Water Environment Research Foundation. Virginia:
Alexandria.
Lim P. E., Tay, M. G., and Mak, K. Y. (2003). The Effect of Heavy metals On
Nitrogen and Oxygen Demand Removal In Constructed Wetlands. Journal of
Environmental Quality.
Lu, J.C.S, Eichenberger, B. and Stearns, R.J. (1985). Leachate From Municipal
Landfills: Production And Management. US: Noyes Publications.
Kadlec, R. H. and Knight, R. L. (1996) Treatment Wetland. USA: Lewis Publishers.
Kadlec, R. H., Knight, R. L., Vymazal, J., Brix, H., Cooper, P. and Haberl, R.
(2000). Constructed Wetlands for Pollution Control: Processes, Performances,
Design and Operation. Scientific and Technical Report No. 8. London, England:
IWA Publishing.
Korkusuz, E. A., Beklioglu, M., and Demirer, G. N. (2005). Comparison of the
treatment performances of blast furnace slag-based and gravel-based vertical
flow wetlands operated identically for domestic wastewater. Bioresource
Technology. 88, 85-94.
Kouezeli-Katsiri, A., Bosdogianni, A., and Christoulas, D. (1999). Prediction Of
Leachate Quality From Sanitary Landfills.
Lim, W. H., Kho, B. L. Tay, T. H. and Low, W. L. (1998). Plants of Putrajaya
Wetlands. Selangor: Putrajaya Holdings Sdn. Bhd. Putrajaya.
Maseri, N. M. (2005). Position Paper on Solid Wastes and Incinerators. The
Malaysia Nature Society. Unpublished.
Mason, C. F. (1998). Biology of Freshwater Pollution. 3rd Edition. England: Addison
Wesley Longman Limited.
Mbuligwe, S.E. (2005). Comparative Treatment of Dye-Rich Wastewater in
Engineered Wetland Systems (EWSs) Vegetated with Different Plants. Water
Research. 39: 271-280.
78
McBean, E. A., Rovers, F. A. and Farquhar, G. J. (1995). Solid Waste Landfill
Engineering and Design. New Jersey: Prentice-Hall.
Michal, B., Surmacz-Gorska, J. and Hung, Y. T. (2004). Treatment of Landfill
Leachate. In: Lawrence, K. Wang, Hung, Y. T., Howard H. L., and Constantine
Y. Handbook of Industrial and Hazardous Wastes Treatment. 2nd Edition. New
York, USA: Marcel Dekker, Inc., 1155-1208.
Mitchell, D. S., Breen, P. F. and Chick, A. J. (1990). Artificial Wetlands for Treating
Wastewaters from Single Households and Small Communities, in Constructed
Wetlands in Water Pollution Control. Oxford, England: Pergamon Press.
Mitsch, W. J. (1992). Landscape Design and The Role of Created, Restored, and
Natural Riparian Wetlands in Controlling Nonpoint Source Pollution. Ecological
Engineering. 12:27-47.
Mitsch, W. J. and Gosselink, J. G. (1986). Wetlands. New York: Van Nostrand
Reinhold Company.
Mitsch, W. J. and Gosselink, J. G. (1993). Wetlands. 2nd Edition. New York: Van
Nostrand Reinhold Company.
Mitsch, W. J., Day, J. W., Zhang, L., and Lane, R. R. (2005). Nitrate-nitrogen
Retention In Wetlands In The Mississippi River Basin. Ecological Engineering.
24: 267-327.
Mitsch, W. J. and Day Jr., J. W. (2006). Restoration Of Wetlands In The Mississippi-
Ohio-Missouri (MOM) River Basin: Experiences And Needed Reseach.
Ecological Engineering. 26: 55-69.
Mitsch, W. J. and Gosselink, (2000). Wetland. Third edition. New York: John Wiley
and Sons, Inc.
Nazaitulshila binti Rasit (2006). Landfill Leachate Treatment Using Subsurface Flow
Constructed Wetlands Enhanced With Magnetic Field. Master Thesis. Universiti
Teknologi Malaysia, Skudai.
Nairn, R. W. and Mitsch, W. J. (2000). Phosphorus Removal In Created Wetland
Ponds Receiving River Overflow. Ecological Engineering. 14: 107-126.
Neralla, S., Weaver, R. W., Lesikar, B. J. and Persyn, R. A. (2000). Improvement of
Domestic Wastewater Quality By Subsurface Flow Constructed Wetlands.
Bioresources Technology. 75, 19-25.
79
Nivala, J., Hoos, M. B., Cross, C., Wallace, S. and Parkin, G. (2006). Treatment of
landfill Leachate Using An Aerated, Horizontal Subsurface-Flow Constructed
Wetland. Science of The Total Environment. doi:10.1016/j.scitotenv.2006.12.030.
Nokes, R. L., Gerba, C. P., and Karpiscak, M. M., (1999). Reduction Of Enteric
Organism In Small-Scale, Subsurface Flow Constructed Wetlands. In: Means, J.
L., Hinchee, R. E. (eds), Wetlands and Remediation: Wastewater Remediation
and Treatment. (pp 195-203). Columbus Ohio: Battelle Press.
Noor Ida Amalina binti Ahamad Nordin (2006). Leachate Treatment Using
Constructed Wetland With Magnetic Field. Master Thesis, Universiti Teknologi
Malaysia, Skudai.
Olson R. K. (1992). Evaluating the Role of Created and Natural Wetlands in
Controlling Non-Point Source Pollution. Ecological Engineering. 12:10-15.
Pankratz, T. M. (2001). Environmental Engineering Dictionary and Directory. New
York: Lewis Publishers.
Patrick, W. H. Jr. and Reddy, K. R. (1976). Nitrification-Denitrification In Flooded
Soils And Water Bottoms: Dependence On Oxygen Supply And Ammonium
Diffusion. Journal of Environmental Quality. 5: 469-472.
Paul, E. A and Clark, F. E. (1996). Soil Microbiology And Biochemistry. 2nd edition.
(pp 340). San Diego, California: Academic Press.
Reddy, K. R. and Patrick, W. H. (1984). Nitrogen transformation and loss in flooded
soils and sediments. CRC Crit Rev Environmental Control. 13: 273-309.
Reed, S. C. and Brown, D. S. (1992). Subsurface Flow Wetlands – A Performance
Evaluation. In: Lim, P. E. and Polprasert, C. Constructed Wetland for
Wastewater Treatment and Resource Recovery. Thailand: Environmental
Systems information Center.
Reed S. C., Middlebrooks, E. J. and Crites, R. W. (1988). Natural Systems for Waste
Management & Treatment. New York: McGraw Hill Inc.
Roser, D. J., McKersie, S. A., Fisher, P. J., Breen, P. F. and Bavor, H. J. (1987).
Sewage Treatment Using Aquatic Plants and Artificial Wetlands. Water 14(3):
20-24.
Rosolen, S. (2000). An Evaluation Of Adsorptive Media For Improving Phosphorus
Removal In Constructed Wetlands. Queen’s University, Kingston, Ontario,
Canada: Master Thesis.
80
Rousseau, D. (2005). Performance of Constructed Treatment Wetlands: Model-
Based Evaluation And Impact Of Operation And Maintenance. PhD thesis in
Applied Biological Sciences: Environmental Technology in Gent University.
Sample, B. E., Shutter II, G. W., Sheaffer, M. B., Jones, D. S., and Efroymson, R. A.
(1997). Ecotoxicological Profiles for Selected Metals and Other Inorganic
Chemicals. US Department of Energy: Tennessee.
Sapkota, D. K. and Bavor, H. J. (1994). Gravel Media Filtration As A Constructed
Wetland Component For The Reduction Of Suspended Solid From Maturation
Pond Effluent. Water Science And Technology. 29(24): 55-66.
Sartaj Majid. (2001). Treatment and Transport Modeling of Landfill Leachate
Contaminants In An Engineered Wetland System. Ph.D. Thesis. University Of
Ottawa. Canada.
Sawidis, T., Chettri, M. K., Papaionnou, A., Zachariadis, G. and Stratis, J. (2001). A
Study of Metal Distribution from Lignite Fuels using Trees as Biological
Monitors. Ecotoxicology Environmental Safety. 48: 27-35.
SBC (2002). Basel Convention Technical Guidelines on Specially Engineered
Landfill. Switzerland: Secretariat of The Basel Convention.
Sharpley, A. N., Chapra, S. C. and Wedepohl, R. (1994). Managing Agricultural
Phosphorus for Protection of Surface Waters: Issues and Options. Journal of
Environmental Quality. 23: 437-451.
Sherwood, C. (1993). Subsurface Flow Constructed Wetlands for Wastewater
Treatment. Proceeding of EPA, A Technology Assessment. USA.
Shutes, R. B. E. (2001). Artificial Wetlands and Water Quality Improvement.
Environment Engineering . (26), 441-447.
Shutes, R. B., Ellis, J. B. Revitt, D. M. and Zhang, T. T. (1993). The Use of Typha
latifolia for Heavy Metal Pollution Control in Urban Wetlands. In: Moshiri, G.
A. (ed.). Constructed Wetlands for Water Quality Improvement. (pp 407-414).
Boca Raton: Lewis Publisher.
Silva, A. C., Dezotti, M. and Sant’ Anna, Jr. G. L. (2003). Treatment and
Detoxication of A Sanitary Landfill Leachate. Chemosphere.
Solano, M. L., Soriano, P., and Ciria, M. P. (2004). Constructed Wetlands As A
Sustainable Solution For Wastewater Treatment In Small Villages. Biosystem
Engineering. 87(1), 109-118.
81
Soltan, M. E. and Rashed, M. N. (2003). Laboratory Study on The Survival od Water
Hyacinth Under Several Conditions of Heavy Metals Concentrations. Advances
on Environmental Research. 7: 321-334.
Spratt, H.G., Morgan, Jr., M.D. and Good, R.E (1987). Sulfate Reduction In Peat
From A New Jersey Pinelands Cedar Swamps. Application Environment
Microbiology. 53: 1406-1411.
Steer, D. N., Fraser, L. H., and Seibert, B. A. (2005). Cell-To-Cell pollution
Reduction Effectiveness Of Subsurface Domestic Treatment Wetlands.
Bioresources Technology. 96, 969-976.
Stephenson, M., Turner, G., Pope, P., Colt, J., Knight, A. and Tchobanoglous, G.
(1980). The Environmental Requirements of Emergent Plants. The Use And
Potential Of Aquatic Species For Wastewater Treatment. Publication No. 65.
Sacramento, California: California State Water Resources Control Board.
Stacie Banks (2004). The Treatment Of Landfill Leachate Using An MF/UF
Membrane System: Focusing On Membrane Fouling. University of Ottawa:
Master Thesis.
Stottmeister, U., Wieβner, A., Kuschk, P., Kappelmeyer, U., Kästner, M., Bederski,
O., Müller, R.A. and Moormann, H. (2003). Effects of Plants and
Microorganisms in Constructed Wetlands for Wastewater Tretment.
Biotechnology Advances. 22: 93-117.
Stowell, R., Ludwig, R., Colt, J., and Tchobanoglous, G. (1981). Concepts in
Aquatic Treatment System Design. Journal of Environmental Engineering.
Proceedings of ASCE 107(EE5): 919-940.
Syed, R. Q. and Walter, C. (1994). Sanitary Landfill Leachate: Generation, Control
and Treatment. Lancaster, Pennsylvania, U.S.A: Technomic Publishing Co. Inc.
Tattersall, S. (2004). Evaluating The Performance and Cost Implications of The
Leachate Treatment System at Arden Quarry Landfill Site. University of Central
Lancashire: MSc Thesis.
Tchobanoglous, G., Theisen, H. and Vicil, S. A. (1993). Integrated Solid Waste
Management. New York: McGraw-Hill Inc.
Thian Siaw Hui (2005). Leachate Treatment By Floating Plants In Constructed
Wetland. Universiti Teknologi Malaysia: MSc Thesis.
Tjasa, G. B. (2006). Ecological Engineering. Long Term Performance of A
Constructed Wetland for Landfill Leachate Treatment. 26: 365-374.
82
Tjasa, B., Danijel, V. and Kukanja, V. (1997). Water Science Technology. The Use
of Constructed Wetlands for Landfill Leachate Treatment. 35 (5): 301-306.
Tousignant, E., Fankhauser, O., and Hurd, S. (1999). Guidance Manual for The
Construction and Operations of Constructed Wetlands for Rural Aplications in
Ontario. Canada.
USEPA (1988), Design Manual Constructed Wetlands and Aquatic Plants Systems
for Municipal Wastewater Treatment. EPA 625/11-88/022. Cincinnati, Ohio:
USEPA CERI.
USEPA (1983), Design Manual Constructed Wetlands and Aquatic Plants Systems
for Municipal Wastewater Treatment. Cincinnati, Cincinnati, Ohio: USEPA
CERI.
USEPA (2000). Wastewater Technology Fact Sheet: Free Water Surface Wetlands.
EPA832-F-00-024.
Uygur, A. and Kargi, F. (2004). Biological Nutrient Removal from Pre-treated
Landfill Leachate in A Sequencing Batch Reactor. Volume 71, Issue 1, pp 9-14.
Vesilind, P. A., Worrell, W. A. and Reinhart D. R. (2002). Solid Waste Enineering.
U.S.A: Brooks/Cole Thompson Learning.
Vymazal, J. (1995). Algae And Element Cycling In Wetlands. (pp 698). Chelsea,
Michigan: Lewis Publishers.
Vymazal, J. (2001). Types of Constructed Wetlands For Wastewater Treatment:
Their Potential For Removal Nutrient. In: Vymal, J. (ed.). Transformation of
Nutrients In Natural and Constructed Wetlands. (pp1-93). Lieden, The
Netherlands: Backhuys Publishers.
Vymazal, J. (2005). Horizontal Sub-Surface Flow and Hybrid Constructed Wetlands
Systems For Wastewater Treatment. Ecological Engineering. 25(2005): 478-490
Vymazal, J. (2006).Removal of Nutrients In Various Types Of Constructed
Wetlands. Science of The Total Environemnt.
doi:10.1016/j.scitotenv.2006.09.014.
Wang, Fenqin (2004). Advanced Oxidation Treatment of Aged Raw and Biologically
Treated Lanfill. University of Alberta: PhD Thesis.
Watson, J. T., Choate, K. D., and Steiner, G. R. (1990). Performance Of Constructed
Wetland Treatment Systems At Benton, Hardin, and Pembrook, Kentucky During
The Early Vegetation Establishment Phase. In: Cooper, P. F., Findlater, B. C.
83
(eds.), Constructed Wetlands In Water Pollution: Advances In Water Pollution
Control. (pp. 171-182). Great Britain: Pergamon Press.
Wetzel, R.G. (1983). Limnoloy. (pp 225-297). Orlando, Florida: Sauders College
Publishing.
Wildeman, T. R. and Laudon, L. S. (1989). Use of Wetlands For Treatment Of
Environmental Problems in Mining: Non-Coal-Mining Applications. In Hammer,
D. A. (ed.). Constructed Wetlands For Wastewater Treatment: Municipal,
Industrial and Agriculture. (pp 221-229). Chelsea: Lewis Publishers.
Wood, A., Scheepers, J. and Hill, M. (1989). Combined Artificial Wetland and High
Rate Algal Pond For Wastewater Treatment and Protein Production. Water
Science and Technology. 21(6/7): 659-668.
APPENDICES
APPENDIX A Standard B under Environmental Quality
85
(Sewage and Industrial Effluent) Regulations 1979
THIRD SCHEDULE
ENVIRONMENTAL QUALITY (SEWAGE AND INDUSTRIAL EFFLUENTS) REGULATIONS 1979
[REGULATIONS 8(1), 8(2), 8(3)]
PARAMETER LIMITS OF EFFLUENTS OF STANDARDS A AND B
____________________________________________________________________
Parameter Unit Standard A B
______________________________________________________________
(1) (2) (3) (4) (i) Temperature 40 40 (ii) pH value - 60-9.0 5.5-9.0 (iii) BOO at 20’C mg/l 20 50 (iv) COD mg/l 50 100 (v) Suspended Solids mg/l 50 100 (vi) Mercury mg/l 0.005 0.05 (vii) Cadmium mg/l 0.01 0.02 (viii) Chromium, Hexavalent mg/l 0.05 0.05 (ix) Arsenic mg/l 0.05 0.10 (x) Cyanide mg/l 0.05 0.10 (xi) Lead mg/l 0.10 0.5 (xii) Chromium, Trivalent mg/l 0.20 1 .0 (xiii) Copper mg/l 0.20 1.0 (xiv) Manganese mg/l 0.20 1.0 (xv) Nickel mg/l 0.20 1.0 (xvi) Tin mg/l 0.20 1.0 (xvii) Zinc mg/l 1 .0 1 .0 (xviii) Boron mg/l 1 .0 4.0 (xix) Iron (Fe) mg/l 1.0 5.0 (xx) Phenol mg/l 0.00 1.0 (xxi) Free Chlorine mg/l 1.0 2.0 (xxii) Suiphide mg/l 0.50 0.50 (xxiii) Oil and Grease mg/l Not Detected 10.0
_________________________________________________________________________
APPENDIX B 86
Laboratory Analysis
Table B1: Pre-treated Leachate (Landfill) and influent for Cell A and B
Parameter Pre-treated Leachate (Landfill)
Influent 50% leachate
concentration (Cell A)
Influent 33% leachate
concentration (Cell B)
Physical Turbidity TSS
6.00 10.20
4.00 4.0
4.0 2.5
Nutrients NH3-N NO3-N P Mn Fe
69.68 70.55 52.70 2.00 0.42
66.95 55.00 4.25 1.15 0.19
27.98 15.30 3.31 1.10 0.21
Organic Matters COD
446.00
286.00
266
Heavy Metals Zn
0.43
0.22
0.07
All units in mg/l except turbidity in FAU (Formazin Attenuation Units) is equivalent to NTU
APPENDIX B 87
Laboratory Analysis
Table B1: Influent and effluent quality at HRT 3 day for Cell A
HRT = 3 day Dilution = 50% leachate, 50% water Soil : sand = 1: 1
Parameter 3 6 9 12 15 NH3-N (inf), mg/l 66.95 66.84 67.95 66.95 66.35 NH3-N (eff), mg/l 53.99 35.58 20.85 19.45 12.85 NH3-N (% removal) 19.36 46.77 69.32 70.96 80.63 NO3-N (inf), mg/l 55.00 54.94 55.48 54.62 54.53 NO3-N (eff), mg/l 35.76 15.40 16.09 12.97 9.34 NO3-N (%removal) 34.98 71.97 70.99 76.25 82.88 PO4
3- (inf), mg/l 4.25 4.05 3.27 3.19 4.38 PO4
3- (eff), mg/l 2.63 1.90 1.83 1.55 1.09 PO4
3- (%removal) 38.24 53.09 44.19 51.41 75.11 COD (inf), mg/l 286 292 288 276 279 COD (eff), mg/l 256 216 154 119 93 COD (%removal) 10.49 26.03 46.60 56.88 66.67 Mn (inf), mg/l 1.15 1.28 2.15 2.16 1.15 Mn (eff), mg/l 0.15 0.52 0.20 0.20 0.15 Mn (%removal) 86.70 54.78 82.61 82.61 86.96 Zn (inf), mg/l 0.32 0.28 0.21 0.22 0.32 Zn (eff), mg/l 0.16 0.01 0.02 0.02 0.04 Zn (%removal) 28.13 97.77 92.86 89.29 84.38 Fe (inf), mg/l 0.29 0.19 0.29 0.16 0.20 Fe (eff), mg/l 0.08 0.07 0.04 0.07 0.05 Fe (%removal) 55.08 62.03 76.47 60.96 74.87 Turbidity (inf), FAU 4.00 4.00 4.00 4.00 4.00 Turbidity (eff), FAU 2.00 2.00 1.00 1.00 1.00 Turbidity (%removal) 50 50 75 75 75
FAU (Formazin Attenuation Units) is equivalent to NTU
APPENDIX B 88
Laboratory Analysis
Table B2: Influent and effluent quality at HRT 6 day for Cell A
HRT = 6 day Dilution = 50% leachate, 50% water Soil : sand = 1: 1
Parameter 6 12 18 24 30 NH3-N (inf), mg/l 66.94 67.30 67.94 66.71 66.95 NH3-N (eff), mg/l 25.58 17.45 15.78 9.90 4.91 NH3-N (% removal) 61.79 74.08 76.78 85.16 92.67 NO3-N (inf), mg/l 55.00 56.00 55.83 56.73 55.00 NO3-N (eff), mg/l 15.40 12.97 11.88 13.23 8.51 NO3-N (%removal) 72.00 76.84 78.72 76.68 84.53 PO4
3- (inf), mg/l 4.98 4.85 4.72 4.82 4.95 PO4
3- (eff), mg/l 0.90 1.05 1.22 0.55 0.64 PO4
3- (%removal) 81.94 78.36 74.15 88.59 87.07 COD (inf), mg/l 286 297 296 285 289 COD (eff), mg/l 216 105 98 64 25 COD (%removal) 24.48 64.65 66.89 77.54 91.35 Mn (inf), mg/l 1.15 2.15 2.33 1.85 2.83 Mn (eff), mg/l 0.52 0.20 0.10 0.13 0.12 Mn (%removal) 54.78 82.61 91.30 89.13 89.57 Zn (inf), mg/l 0.22 1.22 0.42 0.72 0.22 Zn (eff), mg/l 0.01 0.02 0.03 0.04 0.01 Zn (%removal) 97.77 89.29 87.28 84.02 94.96 Fe (inf), mg/l 0.19 0.29 0.28 0.18 0.18 Fe (eff), mg/l 0.07 0.07 0.00 0.03 0.01 Fe (%removal) 62.03 60.96 97.86 82.03 94.44 Turbidity (inf), FAU 4.00 4.00 4.00 4.00 4.00 Turbidity (eff), FAU 1.87 1.00 0.00 0.00 0.00 Turbidity (%removal) 50 75 100 100 100 FAU (Formazin Attenuation Units) is equivalent to NTU
APPENDIX B 89
Laboratory Analysis
Table B3: Influent and effluent quality at HRT 9 day for Cell A
HRT = 9 day Dilution = 50% leachate, 50% water Soil : sand = 1: 1
Parameter 9 18 27 36 45 NH3-N (inf), mg/l 66.95 67.95 65.97 66.73 66.15 NH3-N (eff), mg/l 20.85 15.78 8.87 17.66 16.034 NH3-N (% removal) 68.86 76.79 86.55 73.53 75.76 NO3-N (inf), mg/l 55.00 56.89 56.37 55.92 55.173 NO3-N (eff), mg/l 16.09 18.88 10.40 11.65 16.356 NO3-N (%removal) 70.74 66.81 81.54 79.16 70.36 PO4
3- (inf), mg/l 4.25 4.38 4.67 3.21 3.69 PO4
3- (eff), mg/l 1.83 1.22 1.89 1.57 0.345 PO4
3- (%removal) 57.06 72.15 59.53 51.09 90.65 COD (inf), mg/l 286 227 278 255 248 COD (eff), mg/l 154 135 75 65 55 COD (%removal) 46.22 40.53 73.02 74.51 77.82 Mn (inf), mg/l 1.15 1.25 1.38 1.15 1.15 Mn (eff), mg/l 0.20 0.10 0.12 0.15 0.12 Mn (%removal) 82.61 92.00 91.23 86.96 89.57 Zn (inf), mg/l 0.22 0.22 0.24 0.21 0.24 Zn (eff), mg/l 0.02 0.03 0.02 0.03 0.03 Zn (%removal) 92.86 87.28 90.46 84.63 86.29 Fe (inf), mg/l 0.19 0.29 0.23 0.18 0.17 Fe (eff), mg/l 0.04 0.00 0.02 0.05 0.05 Fe (%removal) 76.47 98.61 90.80 72.30 69.64 Turbidity (inf), FAU 4.00 4.00 4.00 4.00 4.00 Turbidity (eff), FAU 1.00 0.00 0.00 0.00 0.00 Turbidity (%removal) 75 100 100 100 100
FAU (Formazin Attenuation Units) is equivalent to NTU
APPENDIX B 90
Laboratory Analysis
Table B4: Influent and effluent quality at HRT 3 day for Cell B
HRT = 3 day Dilution = 33% leachate, 67% water Soil : sand = 1: 1
Parameter 3 6 9 12 15 NH3-N (inf), mg/l 27.98 27.96 27.88 27.89 27.83 NH3-N (eff), mg/l 4.86 7.20 8.00 5.08 4.70 NH3-N (%removal) 82.63 74.24 71.30 81.80 83.11 NO3-N (inf), mg/l 15.30 15.28 15.20 15.19 15.15 NO3-N (eff), mg/l 13.50 11.20 9.20 6.20 4.10 NO3-N (%removal) 11.76 26.70 39.47 59.18 72.94 PO4
3- (inf), mg/l 3.31 3.29 3.21 3.20 3.16 PO4
3- (eff), mg/l 1.84 1.25 0.74 0.65 0.38 PO4
3- (%removal) 44.41 62.13 77.10 79.69 88.07 COD (inf), mg/l 266 258 263 268 265 COD (eff), mg/l 203 144 127 98 60 COD (%removal) 23.68 44.19 51.71 63.43 77.36 Mn (inf), mg/l 1.10 1.08 1.00 1.10 1.10 Mn (eff), mg/l 0.40 0.40 0.20 0.20 0.10 Mn (%removal) 63.64 62.96 80.00 81.82 90.91 Zn (inf), mg/l 0.07 0.07 0.07 0.07 0.06 Zn (eff), mg/l 0.05 0.06 0.02 0.05 0.05 Zn (%removal) 35.62 17.81 70.59 25.76 19.13 Fe (inf), mg/l 0.21 0.21 0.21 0.21 0.21 Fe (eff), mg/l 0.14 0.15 0.05 0.02 0.02 Fe (%removal) 34.15 29.27 76.10 92.20 91.71 Turbidity (inf), FAU 4.00 4.00 4.00 4.00 4.00 Turbidity (eff), FAU 2.00 2.00 1.00 0.00 0.00 Turbidity (%removal) 50 50 75 100 100
FAU (Formazin Attenuation Units) is equivalent to NTU
APPENDIX B 91
Laboratory Analysis
Table B5: Influent and effluent quality at HRT 6 day for Cell B
HRT = 6 day Dilution = 33% leachate, 67% water Soil : sand = 1: 1
Parameter 6 12 18 24 30 NH3-N (inf), mg/l 28.98 27.84 30.78 28.93 31.58 NH3-N (eff), mg/l 7.20 5.08 8.08 6.30 6.61 NH3-N (%removal) 75.15 81.77 73.76 78.22 79.07 NO3-N (inf), mg/l 15.30 15.10 14.37 14.81 15.92 NO3-N (eff), mg/l 8.20 6.20 1.70 2.40 0.35 NO3-N (%removal) 46.41 58.94 88.17 83.79 97.81 PO4
3- (inf), mg/l 3.31 3.11 2.61 3.44 2.92 PO4
3- (eff), mg/l 0.95 0.65 0.72 0.62 0.07 PO4
3- (%removal) 71.42 79.10 72.34 82.10 97.67 COD (inf), mg/l 266 293 257 268 296 COD (eff), mg/l 144 98 62.00 96.00 55.00 COD (%removal) 45.86 66.55 75.88 64.18 81.42 Mn (inf), mg/l 1.10 1.10 0.95 1.06 1.18 Mn (eff), mg/l 0.40 0.20 0.20 0.20 0.14 Mn (%removal) 63.64 81.82 78.95 81.13 88.14 Zn (inf), mg/l 0.17 0.17 0.07 0.14 0.09 Zn (eff), mg/l 0.06 0.05 0.02 0.03 0.01 Zn (%removal) 65.32 71.68 67.12 76.22 90.32 Fe (inf), mg/l 0.41 0.32 0.51 0.28 0.23 Fe (eff), mg/l 0.15 0.13 0.11 0.07 0.04 Fe (%removal) 64.20 59.46 78.02 75.27 83.04 Turbidity (inf), FAU 4.00 4.00 4.00 4.00 4.00 Turbidity (eff), FAU 2.00 0.50 0.00 0.00 0.00 Turbidity (%removal) 50 87.5 100 100 100
FAU (Formazin Attenuation Units) is equivalent to NTU
APPENDIX B 92
Laboratory Analysis
Table B6: Influent and effluent quality at HRT 9 day for Cell B
HRT = 9 day Dilution = 33% leachate, 67% water Soil : sand = 1: 1
Parameter 9 18 27 36 45 NH3-N (inf), mg/l 30.98 29.98 29.98 32.98 27.98 NH3-N (eff), mg/l 8.00 6.08 5.94 6.943 7.05 NH3-N (%removal) 74.17 79.73 80.18 78.94 74.80 NO3-N (inf), mg/l 20.30 19.30 16.73 16.39 15.30 NO3-N (eff), mg/l 9.20 13.70 13.96 8.18 6.90 NO3-N (%removal) 54.68 29.02 16.56 50.09 54.89 PO4
3- (inf), mg/l 3.31 3.31 4.72 4.13 3.31 PO4
3- (eff), mg/l 0.74 1.22 1.18 0.982 1.46 PO4
3- (%removal) 77.79 63.08 75.00 76.22 55.95 COD (inf), mg/l 289 272 278 291 266 COD (eff), mg/l 127 62.00 187 105 95.00 COD (%removal) 56.06 77.21 32.73 63.92 64.29 Mn (inf), mg/l 1.12 1.10 1.24 1.12 1.10 Mn (eff), mg/l 0.20 0.20 0.36 0.37 0.20 Mn (%removal) 82.14 81.82 70.97 66.96 81.82 Zn (inf), mg/l 0.07 0.05 0.07 0.06 0.07 Zn (eff), mg/l 0.02 0.02 0.03 0.02 0.04 Zn (%removal) 72.60 54.72 53.42 62.50 42.47 Fe (inf), mg/l 0.21 0.24 0.24 0.24 0.31 Fe (eff), mg/l 0.05 0.05 0.05 0.05 0.06 Fe (%removal) 76.10 78.30 78.30 78.30 79.34 Turbidity (inf), FAU 4.00 4.00 4.00 4.00 4.00 Turbidity (eff), FAU 1.00 0.00 0.00 0.00 0.00 Turbidity (%removal) 75 100 100 100 100
FAU (Formazin Attenuation Units) is equivalent to NTU
APPENDIX B 93
Laboratory Analysis
Table B7: Influent and effluent quality at HRT 3 day for control unit
HRT = 3 day Dilution = 100% leachate Soil : sand = 1: 1
Parameter 3 6 9 12 15 NH3-N (inf), mg/l 69.68 70.48 68.38 68.62 69.67 NH3-N (eff), mg/l 60.34 55.21 58.94 28.34 39.14 NH3-N (%removal) 13.40 21.66 13.80 58.70 43.82 NO3-N (inf), mg/l 70.55 69.45 69.52 70.54 70.55 NO3-N (eff), mg/l 68.92 65.92 58.62 53.37 50.92 NO3-N (%removal) 2.30 5.08 15.67 24.34 27.82 PO4
3- (inf), mg/l 52.70 51.62 53.84 53.94 53.80 PO4
3- (eff), mg/l 47.92 45.63 45.77 41.80 41.33 PO4
3- (%removal) 9.07 11.60 14.99 22.50 23.18 COD (inf), mg/l 446.00 450.00 435.00 428.50 403.00 COD (eff), mg/l 105 85 91 86 40 COD (%removal) 76.46 81.04 79.08 80.02 89.98 Mn (inf), mg/l 2.00 2.00 2.00 2.00 2.00 Mn (eff), mg/l 1.53 1.23 1.38 1.55 1.03 Mn (%removal) 23.50 38.50 31.00 22.50 48.50 Zn (inf), mg/l 0.43 0.43 0.43 0.43 0.43 Zn (eff), mg/l 0.07 0.08 0.06 0.04 0.08 Zn (%removal) 84.88 82.56 87.21 91.40 80.93 Fe (inf), mg/l 0.42 0.42 0.42 0.42 0.42 Fe (eff), mg/l 0.37 0.29 0.32 0.18 0.10 Fe (%removal) 11.90 30.95 22.86 57.14 76.19 Turbidity (inf), FAU 6.00 6.00 6.00 6.00 6.00 Turbidity (eff), FAU 4.80 3.90 0.08 0.08 0.08 Turbidity (%removal) 20 35 98.67 98.67 98.67
FAU (Formazin Attenuation Units) is equivalent to NTU
APPENDIX B 94
Laboratory Analysis
Table B8: Influent and effluent quality at HRT 6 day for control unit
HRT = 6 day Dilution = 100% leachate Soil : sand = 1: 1
Parameter 6 12 18 24 30 NH3-N (inf), mg/l 70.48 69.48 69.43 69.78 69.18 NH3-N (eff), mg/l 55.21 60.73 58.73 54.12 50.94 NH3-N (%removal) 21.66 12.59 15.41 22.43 26.36 NO3-N (inf), mg/l 79.45 75.45 78.45 78.33 78.24 NO3-N (eff), mg/l 65.92 55.32 55.03 30.92 25.64 NO3-N (%removal) 17.02 26.68 29.85 60.52 67.23 PO4
3- (inf), mg/l 51.62 49.22 49.62 48.24 48.43 PO4
3- (eff), mg/l 45.63 15.83 10.76 5.93 7.73 PO4
3- (%removal) 11.60 67.84 78.32 87.71 84.04 COD (inf), mg/l 450.00 465.89 460.31 463.55 461.53 COD (eff), mg/l 185 155 95 64 30 COD (%removal) 58.82 66.66 79.29 86.23 93.50 Mn (inf), mg/l 2.00 2.33 2.26 2.06 2.00 Mn (eff), mg/l 1.23 0.76 0.83 0.50 0.48 Mn (%removal) 38.50 67.38 63.27 75.73 76.00 Zn (inf), mg/l 0.43 0.33 0.37 0.35 0.39 Zn (eff), mg/l 0.08 0.05 0.08 0.06 0.08 Zn (%removal) 82.56 84.85 77.57 84.29 79.33 Fe (inf), mg/l 0.48 0.32 0.33 0.27 0.31 Fe (eff), mg/l 0.28 0.17 0.20 0.06 0.05 Fe (%removal) 41.67 46.88 39.39 79.26 83.23 Turbidity (inf), FAU 6.00 6.50 5.50 5.00 5.00 Turbidity (eff), FAU 4.00 3.90 1.90 1.00 0.05 Turbidity (%removal) 33.33 40.00 65.45 80.00 99.00 FAU (Formazin Attenuation Units) is equivalent to NTU
APPENDIX B 95
Laboratory Analysis
Table B9: Influent and effluent quality at HRT 9 day for control unit
HRT = 9 day Dilution = 100% leachate Soil : sand = 1: 1
Parameter 9 18 27 36 45 NH3-N (inf), mg/l 71.38 70.68 70.50 69.98 68.38 NH3-N (eff), mg/l 58.94 48.92 47.52 27.49 20.61 NH3-N (%removal) 17.42 30.78 32.59 60.72 69.86 NO3-N (inf), mg/l 69.52 68.57 68.33 67.93 67.14 NO3-N (eff), mg/l 60.93 60.41 55.82 50.77 50.14 NO3-N (%removal) 12.35 11.90 18.31 25.26 25.32 PO4
3- (inf), mg/l 55.33 54.88 54.27 54.75 55.25 PO4
3- (eff), mg/l 40.62 30.13 19.53 15.92 12.32 PO4
3- (%removal) 26.59 45.10 64.01 70.92 77.70 COD (inf), mg/l 459 447 443 444 400 COD (eff), mg/l 91 174.00 150 85 50.40 COD (%removal) 80.17 61.07 66.14 80.86 87.40 Mn (inf), mg/l 2.00 2.59 2.19 2.20 2.20 Mn (eff), mg/l 1.57 0.64 0.13 0.17 0.10 Mn (%removal) 21.50 75.29 94.06 92.27 95.45 Zn (inf), mg/l 0.43 0.23 0.15 0.10 0.10 Zn (eff), mg/l 0.06 0.06 0.06 0.06 0.06 Zn (%removal) 87.21 76.09 63.33 45.00 45.00 Fe (inf), mg/l 0.42 0.42 0.42 0.42 0.42 Fe (eff), mg/l 0.32 0.22 0.22 0.12 0.12 Fe (%removal) 22.86 46.67 46.67 70.48 70.48 Turbidity (inf), FAU 6.00 6.10 6.18 7.40 7.10 Turbidity (eff), FAU 0.10 0.06 0.06 0.05 0.05 Turbidity (%removal) 98.33 99.02 99.03 99.38 99.35
FAU (Formazin Attenuation Units) is equivalent to NTU
APPENDIX C 96
Analysis of Variance
Table C1: Result of ANOVA for TSSat HRT 3 days
Time (day) 3 6 9 12 15 Control (%) 80.000 80.000 80.000 80.000 99.930 Cell A (%) 85.000 90.000 90.000 90.000 90.000 Cell B (%) 85.000 90.000 90.000 90.000 90.000 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 419.93 83.986 79.44098 Row 2 5 445 89 5 Row 3 5 445 89 5 Column 1 3 250 83.33333 8.333333 Column 2 3 260 86.66667 33.33333 Column 3 3 260 86.66667 33.33333 Column 4 3 260 86.66667 33.33333 Column 5 3 279.93 93.31 32.8683 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 83.80065 2 41.90033 1.687806 0.244603 4.45897Columns 159.1613 4 39.79033 1.602812 0.26395 3.837853Error 198.6026 8 24.82533 Total 441.5646 14
APPENDIX C 97
Analysis of Variance
Table C2: Result of ANOVA for Turbidity at HRT 3 days
Time (day) 3 6 9 12 Control (%) 20.00 35.00 98.67 98.67 98.67 Cell A (%) 50.00 50.00 75.00 75.00 75.00 Cell B (%) 50.00 50.00 75.00 100.00 100.00 Anova: Two-Factor Without Replication SUMMARY Count Sum Average
Row 1 5 351 70.2 1547.533 Row 2 5 325 65 187.5 Row 3 5 375 75 625 Column 1 3 120 40 300 Column 2 3 135 45 75 Column 3 3 248.6667 82.88889 186.7037 Column 4 3 273.6667 91.22222 197.8148 Column 5 3 273.6667 91.22222 197.8148 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 250.1333 2 125.0667 0.601089 0.571212 4.45897Columns 7775.6 4 1943.9 9.342679 0.004151 3.837853Error 1664.533 8 208.0667 Total 9690.267 14
APPENDIX C 98
Analysis of Variance
Table C3: Result of ANOVA for NH3-N at HRT 3 days
Time (day) 3 6 9 12 15 Control (%) 13.398 21.660 13.799 58.697 43.821 Cell A (%) 19.356 46.767 69.316 70.956 80.633 Cell B (%) 82.627 74.244 71.300 81.800 83.109 Anova: Two-Factor Without Replication SUMMARY Count Sum Average Variance
Row 1 5 151.3749 30.27499 405.4545 Row 2 5 287.0281 57.40561 606.4759 Row 3 5 393.0811 78.61622 29.76093 Column 1 3 115.3815 38.4605 1471.908 Column 2 3 142.6717 47.55723 691.7415 Column 3 3 154.415 51.47167 1065.413 Column 4 3 211.4533 70.48442 133.6059 Column 5 3 207.5626 69.18753 484.1329 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 5871.392 2 2935.696 12.8885 0.003147 4.45897Columns 2344.554 4 586.1385 2.573306 0.118899 3.837853Error 1822.211 8 227.7764 Total 10038.16 14
APPENDIX C 99
Analysis of Variance
Table C4: Result of ANOVA for NO3-N at HRT 3 days
Time (day) 3 6 9 12 15 Control (%) 2.303 5.076 15.673 24.341 27.824 Cell A (%) 34.978 71.969 70.993 76.254 82.881 Cell B (%) 11.765 26.702 39.474 59.184 72.937 Anova: Two-Factor Without Replication SUMMARY Count Sum Average Variance
Row 1 5 75.21737 15.04347 127.9607 Row 2 5 337.0759 67.41517 350.7549 Row 3 5 210.0609 42.01219 601.7478 Column 1 3 49.04638 16.34879 282.6692 Column 2 3 103.747 34.58232 1165.263 Column 3 3 126.1397 42.04657 770.048 Column 4 3 159.7786 53.25953 700.0698 Column 5 3 183.6425 61.21417 860.885 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 6859.03 2 3429.515 39.25945 7.31E-05 4.45897Columns 3623.013 4 905.7532 10.36863 0.002976 3.837853Error 698.8411 8 87.35514 Total 11180.88 14
APPENDIX C 100
Analysis of Variance
Table C5: Result of ANOVA for PO43- at HRT 3 days
Time (day) 3 6 9 12 15 Control (%) 9.070 11.604 14.990 22.503 23.178 Cell A (%) 38.235 53.086 44.190 51.411 75.114 Cell B (%) 44.411 62.128 77.103 79.688 88.070 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 81.34534 16.26907 40.45527 Row 2 5 262.0361 52.40723 196.358 Row 3 5 351.3985 70.27969 296.7986 Column 1 3 91.71638 30.57213 356.2838 Column 2 3 126.8181 42.2727 725.8617 Column 3 3 136.2823 45.42743 965.653 Column 4 3 153.6009 51.20031 817.5562 Column 5 3 186.3622 62.12074 1179.338 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 7570.899 2 3785.449 58.40764 1.69E-05 4.45897Columns 1615.961 4 403.9902 6.233372 0.014026 3.837853Error 518.4869 8 64.81086 Total 9705.346 14
APPENDIX C 101
Analysis of Variance
Table C6: Result of ANOVA for COD at HRT 3 days
Time (day) 3 6 9 12 15 Control (%) 76.457 81.040 79.080 80.016 89.975 Cell A (%) 10.490 26.027 46.597 56.884 66.667 Cell B (%) 23.684 44.186 51.711 63.433 77.358 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 406.5694 81.31388 26.33761 Row 2 5 206.6649 41.33297 524.2311 Row 3 5 260.3726 52.07452 409.1651 Column 1 3 110.6311 36.87704 1218.479 Column 2 3 151.2534 50.41781 785.7228 Column 3 3 177.3887 59.12957 305.0663 Column 4 3 200.3332 66.77774 142.1669 Column 5 3 234.0003 78.00011 136.1305 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 4281.323 2 2140.661 19.15993 0.00089 4.45897Columns 2945.127 4 736.2819 6.59007 0.011956 3.837853Error 893.8077 8 111.726 Total 8120.258 14
APPENDIX C 102
Analysis of Variance
Table C7: Result of ANOVA for Mn at HRT 3 days
Time (day) 3 6 9 12 15 Control (%) 23.500 38.500 31.000 22.500 48.500 Cell A (%) 86.696 54.783 82.609 82.609 86.957 Cell B (%) 63.636 62.963 80.000 81.818 90.909 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 164 32.8 118.7 Row 2 5 393.6522 78.73043 183.6733 Row 3 5 379.3266 75.86532 148.7163 Column 1 3 173.832 57.94401 1022.725 Column 2 3 156.2456 52.08186 155.0797 Column 3 3 193.6087 64.53623 845.2105 Column 4 3 186.9269 62.30896 1188.721 Column 5 3 226.3656 75.4552 548.843 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 6620.726 2 3310.363 29.41132 0.000205 4.45897Columns 903.9264 4 225.9816 2.007761 0.186292 3.837853Error 900.4324 8 112.554 Total 8425.085 14
APPENDIX C 103
Analysis of Variance
Table C8: Result of ANOVA for Fe at HRT 3 days
Time (day) 3 6 9 12 15 Control (%) 11.905 30.952 22.857 57.143 76.190 Cell A (%) 55.08 62.03 76.47 60.96 74.87 Cell B (%) 34.146 29.268 76.098 92.195 91.707 Anova: Two-Factor Without Replication SUMMARY Count Sum Average Variance
Row 1 5 199.0476 39.80952 692.1315 Row 2 5 329.4118 65.88235 87.13432 Row 3 5 323.4146 64.68293 951.0529 Column 1 3 101.1313 33.71044 466.1724 Column 2 3 122.2528 40.75092 340.3751 Column 3 3 175.4253 58.4751 951.5138 Column 4 3 210.3005 70.10018 369.7873 Column 5 3 242.7641 80.92137 87.69088 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 2166.529 2 1083.264 3.826859 0.068217 4.45897Columns 4656.725 4 1164.181 4.112715 0.042302 3.837853Error 2264.55 8 283.0688 Total 9087.804 14
APPENDIX C 104
Analysis of Variance
Table C9: Result of ANOVA for TSS at HRT 6 days
Time (day) 6 12 18 24 30 Control (%) 80.000 85.000 90.000 100.000 100.000 Cell A (%) 85.000 90.000 90.000 90.000 90.000 Cell B (%) 85.000 90.000 90.000 90.000 90.000 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 455 91 80 Row 2 5 445 89 5 Row 3 5 445 89 5 Column 1 3 250 83.33333 8.333333 Column 2 3 265 88.33333 8.333333 Column 3 3 270 90 0 Column 4 3 280 93.33333 33.33333 Column 5 3 280 93.33333 33.33333 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 13.33333 2 6.666667 0.347826 0.716393 4.45897Columns 206.6667 4 51.66667 2.695652 0.108483 3.837853Error 153.3333 8 19.16667 Total 373.3333 14
APPENDIX C 105
Analysis of Variance
Table C10: Result of ANOVA for Turbidity at HRT 6 days
Time (day) 6 12 18 24 30 Control (%) 33.33 40.00 65.45 80.00 99.00 Cell A 50.00 75.00 100.00 100.00 100.00 Cell B 50.00 87.50 100.00 100.00 100.00 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 317.7879 63.55758 749.6454 Row 2 5 425 85 500 Row 3 5 437.5 87.5 468.75 Column 1 3 133.3333 44.44444 92.59259 Column 2 3 202.5 67.5 606.25 Column 3 3 265.4545 88.48485 397.7961 Column 4 3 280 93.33333 133.3333 Column 5 3 299 99.66667 0.333333 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 1732.112 2 866.056 9.510584 0.007683 4.45897Columns 6145.083 4 1536.271 16.87054 0.000577 3.837853Error 728.4987 8 91.06234 Total 8605.694 14
APPENDIX C 106
Analysis of Variance
Table C11: Result of ANOVA for NH3-N at HRT 6 days
Time (day) 6 12 18 24 30 Control (%) 21.660 12.587 15.405 22.432 26.356 Cell A 61.787 74.079 76.781 85.160 92.672 Cell B 75.151 81.768 73.762 78.220 79.066 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 98.44098 19.6882 31.16248 Row 2 5 390.4782 78.09564 136.5552 Row 3 5 387.9658 77.59316 10.15704 Column 1 3 158.5978 52.86594 775.0018 Column 2 3 168.4336 56.14452 1437.706 Column 3 3 165.9481 55.31604 1196.94 Column 4 3 185.8113 61.93709 1182.525 Column 5 3 198.0942 66.0314 1226.866 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 11274.45 2 5637.223 124.0205 9.53E-07 4.45897Columns 347.867 4 86.96676 1.913293 0.201655 3.837853Error 363.6318 8 45.45397 Total 11985.94 14
APPENDIX C 107
Analysis of Variance
Table C12: Result of ANOVA for NO3-N at HRT 6 days
Time (day) 6 12 18 24 30 Control (%) 17.024 26.675 29.849 60.523 67.227 Cell A (%) 72.000 76.839 78.716 76.681 84.535 Cell B (%) 46.405 58.940 88.170 83.795 97.808 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 201.2987 40.25974 492.6644 Row 2 5 388.7707 77.75415 20.49963 Row 3 5 375.1184 75.02367 461.6435 Column 1 3 135.4296 45.1432 756.7749 Column 2 3 162.4547 54.15158 646.3119 Column 3 3 196.7349 65.57829 979.7828 Column 4 3 220.999 73.66632 142.2032 Column 5 3 249.5696 83.18988 235.1601 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 4369.694 2 2184.847 15.18874 0.001888 4.45897Columns 2748.458 4 687.1145 4.776721 0.028977 3.837853Error 1150.772 8 143.8465 Total 8268.924 14
APPENDIX C 108
Analysis of Variance
Table C13: Result of ANOVA for PO43- at HRT 6 days
Time (day) 6 12 18 24 30 Control (%) 11.604 67.838 78.315 87.706 84.039 Cell A (%) 81.942 78.359 74.153 88.589 87.071 Cell B (%) 71.420 79.100 72.337 82.099 97.671 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 329.503 65.9006 977.6224 Row 2 5 410.1141 82.02282 35.9917 Row 3 5 402.6269 80.52537 112.1111 Column 1 3 164.9662 54.98873 1439.354 Column 2 3 225.2974 75.09913 39.67699 Column 3 3 224.8049 74.93497 9.393355 Column 4 3 258.3941 86.13136 12.39092 Column 5 3 268.7814 89.59381 51.23071 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 793.4205 2 396.7103 1.37349 0.307054 4.45897Columns 2192.23 4 548.0576 1.897484 0.204372 3.837853Error 2310.671 8 288.8338 Total 5296.322 14
APPENDIX C 109
Analysis of Variance
Table C14: Result of ANOVA for COD at HRT 6 days
Time (day) 6 12 18 24 30 Control (%) 58.818 66.662 79.292 86.232 93.496 Cell A (%) 24.476 64.646 66.892 77.536 91.349 Cell B (%) 45.865 66.553 75.875 64.179 81.419 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 384.4995 76.89991 200.0045 Row 2 5 324.8993 64.97987 624.3453 Row 3 5 333.8911 66.77821 185.3234 Column 1 3 129.158 43.05265 300.7781 Column 2 3 197.861 65.95367 1.284556 Column 3 3 222.0596 74.01986 41.02451 Column 4 3 227.9474 75.98247 123.3963 Column 5 3 266.2639 88.75465 41.5111 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 412.9501 2 206.475 2.739127 0.124115 4.45897Columns 3435.653 4 858.9133 11.39446 0.002188 3.837853Error 603.0391 8 75.37989 Total 4451.643 14
APPENDIX C 110
Analysis of Variance
Table C15: Result of ANOVA for Mn at HRT 6 days
Time (day) 6 12 18 24 30 Control (%) 38.500 67.382 63.274 75.728 76.000 Cell A (%) 54.783 82.609 91.304 89.130 89.565 Cell B (%) 63.636 81.818 78.947 81.132 88.136 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 320.8845 64.17689 235.9019 Row 2 5 407.3913 81.47826 233.6106 Row 3 5 393.6696 78.73392 82.90926 Column 1 3 156.919 52.30632 162.5582 Column 2 3 231.8089 77.26962 73.48034 Column 3 3 233.5261 77.84202 197.3367 Column 4 3 245.9907 81.99689 45.4662 Column 5 3 253.7008 84.56694 55.55526 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 864.6261 2 432.3131 16.93956 0.001332 4.45897Columns 2005.52 4 501.3799 19.64584 0.000337 3.837853Error 204.1673 8 25.52091 Total 3074.313 14
APPENDIX C 111
Analysis of Variance
Table C16: Result of ANOVA for Fe at HRT 6 days
Time (day) 6 12 18 24 30 Control (%) 41.667 46.875 39.394 79.259 83.226 Cell A (%) 62.03 60.96 97.86 82.03 94.44 Cell B (%) 64.198 59.464 78.020 75.273 83.043 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 290.4207 58.08413 456.2477 Row 2 5 397.3262 79.46524 303.8634 Row 3 5 359.9972 71.99944 96.7363 Column 1 3 167.8963 55.96543 154.5132 Column 2 3 167.3012 55.76708 59.86349 Column 3 3 215.2747 71.75823 884.0036 Column 4 3 236.5641 78.85469 11.54499 Column 5 3 260.7078 86.9026 42.60073 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 1177.543 2 588.7714 4.177501 0.057248 4.45897Columns 2299.88 4 574.9701 4.079577 0.043148 3.837853Error 1127.509 8 140.9387 Total 4604.933 14
APPENDIX C 112
Analysis of Variance
Table C17: Result of ANOVA for TSS at HRT 9 days
Time (day) 9 18 27 36 45 Control (%) 95.00 95.00 100.00 100.00 100.00 Cell A (%) 95.00 90.00 95.00 100.00 100.00 Cell B (%) 95.00 90.00 95.00 100.00 100.00 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 490 98 7.5 Row 2 5 480 96 17.5 Row 3 5 480 96 17.5 Column 1 3 285 95 0 Column 2 3 275 91.66667 8.333333 Column 3 3 290 96.66667 8.333333 Column 4 3 300 100 0 Column 5 3 300 100 0 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 13.33333 2 6.666667 2.666667 0.1296 4.45897Columns 150 4 37.5 15 0.000868 3.837853Error 20 8 2.5 Total 183.3333 14
APPENDIX C 113
Analysis of Variance
Table C18: Result of ANOVA for Turbidity at HRT 9 days
Time (day) 9 18 27 36 45 Control (%) 98.33 99.02 99.03 99.38 99.35 Cell A (%) 75.00 100.00 100.00 100.00 100.00 Cell B (%) 75.00 100.00 100.00 100.00 100.00 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 495.1093 99.02187 0.177581 Row 2 5 475 95 125 Row 3 5 475 95 125 Column 1 3 248.3333 82.77778 181.4815 Column 2 3 299.0164 99.67213 0.322494 Column 3 3 299.0291 99.67638 0.314199 Column 4 3 299.3784 99.79279 0.128804 Column 5 3 299.3521 99.78404 0.139919 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 53.9181 2 26.95905 0.693802 0.527401 4.45897Columns 689.8546 4 172.4637 4.438424 0.034986 3.837853Error 310.8557 8 38.85696 Total 1054.628 14
APPENDIX C 114
Analysis of Variance
Table C19: Result of ANOVA for NH3-N at HRT 9 days
Time (day) 9 18 27 36 45 Control (%) 17.422 30.782 32.593 60.717 69.857 Cell A (%) 68.857 76.785 86.554 73.529 75.761 Cell B (%) 74.173 79.733 80.183 78.945 74.799 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 211.3714 42.27429 486.104 Row 2 5 381.4872 76.29745 42.18772 Row 3 5 387.8329 77.56658 8.154833 Column 1 3 160.4521 53.48405 982.4131 Column 2 3 187.2999 62.43331 753.539 Column 3 3 199.3309 66.44362 869.552 Column 4 3 213.1912 71.06372 87.61744 Column 5 3 220.4175 73.47249 10.03312 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 4007.886 2 2003.943 11.46402 0.004477 4.45897Columns 747.363 4 186.8408 1.068865 0.431701 3.837853Error 1398.423 8 174.8029 Total 6153.672 14
APPENDIX C 115
Analysis of Variance
Table C20: Result of ANOVA for NO3-N at HRT 9 days
Time (day) 9 18 27 36 45 Control (%) 12.350 11.900 18.308 25.261 25.320 Cell A (%) 70.740 66.808 81.543 79.161 70.355 Cell B (%) 54.680 29.016 16.557 50.092 54.889 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 93.13984 18.62797 43.39165 Row 2 5 368.6076 73.72152 39.6984 Row 3 5 205.2328 41.04657 300.9416 Column 1 3 137.7697 45.92322 909.8607 Column 2 3 107.7237 35.90789 789.3402 Column 3 3 116.4087 38.80289 1370.828 Column 4 3 154.5141 51.50471 727.8004 Column 5 3 150.5642 50.18806 523.6075 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 7675.91 2 3837.955 31.75263 0.000157 4.45897Columns 569.1628 4 142.2907 1.177216 0.389715 3.837853Error 966.9639 8 120.8705 Total 9212.037 14
APPENDIX C 116
Analysis of Variance
Table C21: Result of ANOVA for PO43- at HRT 9 days
Time (day) 9 18 27 36 45 Control (%) 26.586 45.098 64.013 70.922 77.701 Cell A (%) 57.059 72.146 59.529 51.090 90.650 Cell B (%) 77.795 63.082 75.000 76.223 55.952 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 284.3213 56.86427 434.5339 Row 2 5 330.4746 66.09492 247.3725 Row 3 5 348.0506 69.61011 92.23459 Column 1 3 161.4393 53.81311 663.4818 Column 2 3 180.3261 60.1087 189.5233 Column 3 3 198.5422 66.18072 63.36208 Column 4 3 198.2355 66.07849 175.507 Column 5 3 224.3034 74.76781 307.455 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 433.3634 2 216.6817 0.73287 0.510201 4.45897Columns 731.2691 4 182.8173 0.618332 0.661997 3.837853Error 2365.295 8 295.6619 Total 3529.927 14
APPENDIX C 117
Analysis of Variance
Table C22: Result of ANOVA for COD at HRT 9 days
Time (day) 9 18 27 36 45 Control (%) 80.174 61.074 66.140 80.856 87.400 Cell A (%) 46.224 40.529 73.022 74.510 77.823 Cell B (%) 56.055 77.206 32.734 63.918 64.286 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 375.6439 75.12879 121.795 Row 2 5 312.1064 62.42128 309.3365 Row 3 5 294.1983 58.83966 270.5075 Column 1 3 182.4534 60.81781 305.1701 Column 2 3 178.8083 59.60278 337.9281 Column 3 3 171.8954 57.29845 464.4053 Column 4 3 219.2832 73.0944 73.22929 Column 5 3 229.5083 76.50276 134.874 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 732.7407 2 366.3703 1.543853 0.271015 4.45897Columns 908.0833 4 227.0208 0.956646 0.480352 3.837853Error 1898.473 8 237.3091 Total 3539.297 14
APPENDIX C 118
Analysis of Variance
Table C23: Result of ANOVA for Mn at HRT 9 days
Time (day) 9 18 27 36 45 Control (%) 21.500 75.290 94.064 92.273 95.455 Cell A (%) 76.098 78.298 78.298 78.298 79.344 Cell B (%) 82.143 81.818 70.968 66.964 81.818 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 378.5808 75.71615 984.9846 Row 2 5 390.3354 78.06709 1.417499 Row 3 5 383.7112 76.74225 52.41256 Column 1 3 179.7404 59.91347 1115.833 Column 2 3 235.4056 78.46854 10.67752 Column 3 3 243.3295 81.10985 139.2888 Column 4 3 237.5349 79.1783 160.7107 Column 5 3 256.617 85.539 75.26865 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 13.89159 2 6.945794 0.018586 0.981628 4.45897Columns 1165.594 4 291.3984 0.779749 0.568659 3.837853Error 2989.665 8 373.7081 Total 4169.15 14
APPENDIX C 119
Analysis of Variance
Table C24: Result of ANOVA for Fe at HRT 9 days
Time (day) 9 18 27 36 45 Control (%) 22.857 46.667 46.667 70.476 70.476 Cell A (%) 76.47 98.61 90.80 72.30 69.64 Cell B (%) 82.609 92.000 91.232 86.957 89.565 Anova: Two-Factor Without Replication
SUMMARY Count Sum Average Variance Row 1 5 257.1429 51.42857 396.8254 Row 2 5 407.8127 81.56253 157.4408 Row 3 5 442.3623 88.47246 14.48347 Column 1 3 181.9364 60.64548 1080.388 Column 2 3 237.2729 79.09098 799.4128 Column 3 3 228.6986 76.23285 655.666 Column 4 3 229.7278 76.57593 81.64458 Column 5 3 229.6821 76.56071 127.0124 ANOVA
Source of Variation SS df MS F P-value F crit
Rows 3880.088 2 1940.044 9.651005 0.007372 4.45897Columns 666.8394 4 166.7099 0.82932 0.542431 3.837853Error 1608.159 8 201.0199 Total 6155.086 14
APPENDIX D
Figures Of The Whole Experiment
120
Plate D2: Each cell filled with large gravel,
medium gravel and sand
Sand Gravel
Medium Gravel
Large Gravel
Plate D1: Constructed wetlands made of concrete,
divided by 3 cells, build in front of the environmental
laboratory
APPENDIX D
Figures Of The Whole Experiment
121
Plate D4: All three cells wash out with tap water to clean
all the debris that trapped in the CWs
Plate D3: After all the filling complete
APPENDIX D
Figures Of The Whole Experiment
122
Plate D5: Domestic wastewater taken from oxidation
pond in UTM
Plate D6: Domestic wastewater then fed into the
CWs to acclimatize the plant as long as 1 week
APPENDIX D
Figures Of The Whole Experiment
123
Plate D7: (a) Secondary Treatment of Landfill Leachate (b) About 23 bottles
samples is required for this study (c) Method of collected landfill leachate
(d) Method of collected landfill leachate
(a)
(d) (c)
(b)
APPENDIX D
Figures Of The Whole Experiment
124
Plate D8: Dilution of landfill leachate before poured into the CWs
Plate D9: Leave the CWs with leachate for 3-5 day for plant to adopt a new environment
APPENDIX D
Figures Of The Whole Experiment
125
Plate D10: During experiment
Plate D11: Before and after treatment by using a
FWSCW
Before treatment
After treatment
From landfill