zero energy compact unit (zecu) for sewage treatment in ... · construction, operation and...

Zero Energy Compact Unit (ZECU) for Sewage

Treatment in Small Communities in Egypt

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Dr. Tarek Ismail Sabry

Professor, Public Works Department, Faculty of Engineering

Ain Shams University

Dr. Ahmed S. El-Gendy

Associate Professor, Dept. of Construction and Architectural Engineering,

The American University in Cairo

Dr. F. A. El-Gohary

Emeritus Professor, National

Research Center (NRC),

Introduction and Problem Definition

• Substantial efforts and resources have been directed by the Government of Egypt to improving access, reliability and quality of water services both in urban and rural areas.

• Priority to expansion of water supply and sanitation services coverage is in urban areas than in rural areas.

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Rural sanitation: a remaining challenge

Egypt suffers from low coverage of appropriate

sanitation systems in rural areas.

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• The updated number of small communities in

rural Egypt which suffer from lack of sanitation

services include about 3,170 villages and

26,542 hamlets (Ezba or Naga)

• This is approximately about 50 million capita

that do not have access to proper sanitation

services.

Cesspits effluents infiltrate through the soil and cause serious

contamination of ground water and the nearby canals and drains.

(Health and Environmental risk)

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The degradation of

environmental

quality and health is

severe due to the

uncontrolled

disposal of the

untreated sewage.


• Conventional Centralized sewage treatment has high cost of construction, operation and maintenance

• In addition, it requires skilled labor

and large footprint.

• Decentralized onsite compacted

low cost treatment models are the solution to serve small communities in Egypt.

• Onsite treatment help in improving the water quality of drains and canals and other water bodies.

• Therefore, new configurations employing the best practices of sanitation technology for wastewater treatment in rural areas of Egypt are highly needed.

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• Upflow Septic tank followed by anaerobic Baffled Reactor

(USBR) as a new concept of low cost technology employing

two stages anaerobic treatment for sewage treatment

proved to be able to efficiently treat wastewater (Sabry

and Sung, 2004).

• This technology is also easy to implement and operate.

Therefore, it would be more convenient for the conditions

of rural areas in Egypt.


System Development and State

of the Art

System Development and State of the Art

Using Upflow Septic Baffled Reactor (USBR)

Low cost new technology suitable for tackling rural sanitation

problems.

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Wastewater Treatment system at

El-Arab Village, Ismailia

Governorate (200 Capita)

2005

Project Cost 100,000 L.E.


Abo-Halifa, Ismailia Governorate

(100 Capita)

2005



Aabdel-Kareem Issa Village, El-

Fayoum Governorate (2000

Capita)

2006


Wastewater Treatment system

at Juhaina Factory, El-Ras

City – KSA (250 Capita)

2009

Project Cost 310,000 Saudi

Riyals

Technical and financial comparison among different treatment technologies

Treatment system

Removal efficiency %

Land Area

m2 / m3/ day

Construction Cost

L.E* /m3

Running Cost

L.E* /m3

Nuisance (fly, smell)

Operation Complex

BOD5 pathogenic Bacteria

Activated sludge

75-95 60-90 2.4 2400-4000 250 low high

Oxidation ditches

75-95 60-90 6 1700 137 low high

Trickling filters

65-85 60-90 3.6 1600 55 low to

medium

medium

Aerated ponds

80-95 60-90 19.2 1500- 1600 66 low medium

Oxidation ponds

80-95 99-99.9 24 1200-2500 27 medium to high

low

USBR 80- 85 undetected 1- 1.4 1500 25 low low

Best performed technology

Activated Sludge

Oxidation Ponds

USBR USBR USBR Activated sludge

USBR

* LE= Egyptian Pound, $ Dollar= 5.3 LE Pounds according to the currency value at October 2008.

However, the USBR system in its current shape, still

occupies a relatively large area of land.

Bearing to the fact that land availability in a major part of

the inhabited rural areas in Egypt (for example, the Nile

Delta) is limited and expensive, the use of the USBR for

sewage treatment in these areas might be not quite

appropriate.

Therefore, a new treatment system with a smaller

footprint and a similar concept of the USBR has been

constructed and tested (Sabry et al., 2011).

This treatment system is a compact system. It consists

of an up-flow anaerobic reactor and down-flow

anaerobic packed-bed baffled reactor followed by a

passive aeration, aerobic biological filter, and sand

filter for improving the effluent quality of the two-

stage anaerobic system at different operating

conditions.

Pilot-Scale (Zenien WWTP in Giza Governorate)

Flow rate = 0.5 m3/d

The USBR has been developed and renamed as Zero

Energy Compact Unit (ZECU)

Pilot-Scale Process Diagram

Flow rate = 9.0 m3/d

Full-Scale (ZECU)

(Zawyet El-Karatzah in El-Fayoum Governorate)

Aerial Photos for the Location of the Full-Scale Setup at Zawyat El-Karatsah

WWTP in El-Fayyoum Governorate - Egypt

Perforated

Trays

Biological Filter

Sedimentation

Tank next to

Slow Sand

Filter

Tower contains

the three

reactors of the

anaerobic

stage

Different Treatment Units of the Full-Scale System after being assembled and

installed at Zawyat El-Karatsah WWTP

Inlets and Outlets of the Full-Scale System

Force main of the

raw sewage (from

the submersible

pump)

Influent of the

Full-Scale (at the

First Reactor in

the two modules)

Cones for gas

collection from the

First Reactor in each

module

Final Effluent of

each Module

Ladder for

Inspection and

System

Maintenance

Effluent of the

Anaerobic Stage

Effluent of the Anaerobic Stage and the Perforated Trays

Effluent of the Anaerobic Stage trickling through the Perforated Trays

(During Testing of the System)

Effluent of the

Anaerobic Stage

Perforated Trays

Perforated

Trays

Trickled

Wastewater

Aerobic Biological Filter packed with Sponge

Vents for

aeration of the

Biological

Filter

Sponge

Media

Perforated

Trays

Aerobic Biological Filter with Air Vents on its Side Wall

Air Vents

Air Vents

Points of Strength

Existence of “KNOW HOW”

Existence of successful projects

Passive system

Low cost treatment

Locally manufactured

Small foot-print area

Simple in operation

No need for skilled labors

Little maintenance

Provide effluents that comply with the limits regarding disposal in agricultural drains or Effluent Reuse in irrigation

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Results and Data Analysis

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Results and Data Analysis (cont’d)

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Parameter Raw Effluent of the

anaerobic stages Final Effluent

Temperature, oC (20 + 3)

pH (7.1 + 0.1) (7.4 + 0.1) (7.5 + 0.1)

COD – Total, mg/L 300 – 475 (389) 128 – 453 (275) 24 – 98 (58)

COD – Soluble, mg/L 89 – 126 (106) 48 – 142 (87) 18 – 63 (33)

BOD, mg/L 174 – 294 (222) 90 – 255 (152) 12 – 49 (28)

TSS, mg/L 110 – 310 (217) 69 – 324 (177) 6 – 40 (20)

VSS, mg/L 39 – 160 (93) 25 – 195 (79) 3 – 21 (10)

At optimum hydraulic loading rate of the biological filter (1.64 m3/m2/d) – Summary of system performance [range and (average)]


Parameter

Effluent, range and (typical or average) concentrations - mg/l

Onsite wastewater treatment systems (septic tank)

Bradley et al.

(2002)

Converse and

Converse (1999)

USEPA

(2002) Current System

BOD 150 – 250 (180) 32 – 548 (192) 46 – 156 (93.5) 12 – 49 (28)

TSS 40 – 140 (80) 14 – 626 (87) 6 – 40 (20)

Comparison of Onsite Wastewater Treatment Systems (OWTS) and the Current System Effluent Quality (at optimum hydraulic loading rate of the biological filter)


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Conclusions

The use of passive aeration after the anaerobic phases of

the treatment increases the dissolved oxygen contents of

the anaerobic effluent by 6 folds to reach an average

concentration of 5.22 mg/L.

The added oxygen activates the aerobic attached-growth

microorganisms which play the main role of wastewater

treatment in the biological filter system.

Among the tested hydraulic loading rates of 1.09, 1.64

and 3.27 m3/m2.d, the highest removal efficiencies of

CODTotal, CODsoluble, BOD5, TSS and VSS from

wastewater were obtained at the hydraulic loading rate of

1.64 m3/m2.d.

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Conclusions

At optimum hydraulic loading rate, average overall

removal efficiencies of 85%, 88%, 91% and 89% can be

achieved for CODTotal , BOD5, TSS and VSS, respectively.

Overall, the integration of anaerobic and aerobic phases of

the treatment can provide effluents with quality

acceptable for disposal in agricultural drains according to

Law 48 for the Year 1982 with respect to CODTotal, BOD5

and TSS.

SELECTED PUBLICATION: El-Gendy, A. S., T.I.M. Sabry, and F. A. El-Gohary (2012). The Use of AN Aerobic Biological

Filter for Improving the Effluent Quality of A Two-Stage Anaerobic System. Sixteenth International Water Technology Conference, IWTC 16 2012, Istanbul, Turkey, May 17-21.

Sabry, T.I.M., A. S. El-Gendy and F. A. El-Gohary (2011). An Integrated Anaerobic – Aerobic System for Wastewater Treatment In Rural Areas. IWA Conference 2011 Small Sustainable Solutions for Water, Venice, April 18-22.

Sabry, T.I.M. (2010): Evaluation of decentralized treatment of sewage employing Upflow Septic Tank/Baffled Reactor (USBR) in developing countries.

Journal of Hazardous Materials, ELSEVIER, 174 (2010) 500–505 Ghobrial, F. H., Sabry, T.I.M., Wahb, I, S, and Osman M. (2008). Establishing Design Criteria

for the Up Flow Septic Tank / Baffled Reactor (USBR) Use in Rural Egypt. Scientific newsletter, Faculty of engineering, El Azhar University. Vol. 30, No. 3, October 2008, pp. 1123- 1133.

Sabry, T.I.M. (2007): Application of the UASB inoculated with flocculent and granular sludge in treating sewage at different hydraulic shock loads. Bioresource Technology, ELSEVIER, 99 (2008) 4073–4077.

Sabry, T.I.M. (2007), "دراسة فنية واقتصادية"استخدام تكنولوجيا جديدة منخفضة التكاليف في معالجة مياه الصرف الصحي

.2007ديسمبر 5-2المؤتمر الهندسي السعودي السابع بجامعة الملك سعود في الفترة بين - Sabry, T.I.M., and Sung, S. (2007): Demonstration of The Modified Septic Tank (USBR) for

Rural Wastewater Treatment in Egypt European Water and Wastewater Management Conference, Aqua Enviro, Newcastle, England, 24th – 26th September 2007.

Acknowledgements

• The current research is funded by the Science

and Technology Development Fund, STDF,

Egypt, Grant No 940.

Thank you

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