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REACTION RATE KINETICS STUDY BIODIESEL EFFLUENT WASTE

USING THE FLUIDIZED BED BIO REACTOR

A thesis submitted

In partial fulfilment of

Requirements for the award of degree of

MASTER OF ENGINEERING

IN

CIVIL ENGINEERING

Environmental Engineering and Management

BY

CHIRANJEEVI.J Regd. No.3102206308010

Under The Guidance of

Prof Dr. G.V.R.SRINIVASA RAO B.E (CIVIL), M.E. (ENV.ENGG), Ph.D

DEPARTMENT OF CIVIL ENGINEERING ANDHRA UNIVERSITY COLLEGE OF ENGINEERING (A)

VISAKHAPATNAM 2012-14

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ANDHRA UNIVERSITY COLLEGE OF ENGINEERING

DEPARTMENT OF CIVIL ENGINEERING (A)

M.E.THESIS EVALUATION REPORT

This thesis is entitled REACTION RATE KINETICS STUDY BIODIESEL

EFFLUENT WASTE USING THE FLUIDIZED BED BIO REACTOR

submitted by Mr CHIRANJEEVI .Jof 2012-14 batch in the partial fulfilment of the

requirements for the award of the degree of Master of Engineering with specialization in

ENVIRONMENTAL ENGINEERING AND MANAGEMENT, Visakhapatnam, has been

approved.

Examiners:

1) Research Director

2). External Examiner

3). Chairman Board of Studies in

Civil Engineering

4). Head of the Department Civil Engineering

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ACKNOWLEDGEMENTS I would like to

express my deep sense of gratitude and sincere thanks to Dr.G.V.R.Srinivasa Rao Professor,

Engineering Environmental Division for their guidance, invaluable suggestions and constant

encouragement extended at all the stages of the dissertation work.

I take this opportunity to express my gratitude to Prof. B.S.N.Raju, Head of the

Department of Civil Engineering, for his valuable suggestions and encouragement throughout

my work.

It is my privilege to express my gratitude to Prof. P.MalleswarRao,Chairman Board of

Studies, Department of Civil engineering

I would also like to express my sincere thanks to sri. K.Srinivasa Murthy, working as a

Lecturer in department of Civil Engineering M.R.A.G.R.Government Polytechnic College

Vizianagaram.

I am thankful to all the faculty members of Public Health and Environmental Engineering

Division of Civil Engineering Department for their kind advice and support.

I Sincerely thank Dr S.L. Narasimha Rao, PH&EE lab, For his support and guidance

during experimental work. My thanks are due to the technical and non-technical staff of Public

Health and Environmental Engineering Laboratory for their support during my experimentation

in the laboratory.

I would like to express my special thanks to all of my friends for their helping attitude

during the entire duration of my M.E Project. My parents contributed significantly to bring me to

this day.

.

CHIRANJEEVI.J

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CONTENTS

TITLE Page.No

Certificate

Evaluation Report

Acknowledgements

Chapter 1: Introduction

1.1 Introduction

1.1.1 Environmental engineering

1.1.2 Industrial wastes

1.1.3 Bio diesel &itseffluents

1.1.4 Fluidized bed bioreactor

1.2 Necessity and Objective of the study

1.3 Scope of the Work

1.4 Limitations

Chapter 2: Theory and Literature Review

2.1 Introduction

2.2 Industrial Wastewater Treatment

2.2.1 BIOLOGICAL TREATMENT OF INDUSTRIAL WASTES

2.2.2 Biological Aerobic Treatment

2.2.3 Advantages

2.2.4 Biological Anaerobic Treatment

2.3 Basic types of reactors

2.4 Examples of biological reactors used as ETPs

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2.4.1 Bioreactors

2.5 Fluidization

2.6 Fluidized Bed Bioreactors (FBBR)

2.6.1 Principle

2.6.2 Construction Features

2.6.3 Mechanism

2.6.4 Factors Affecting Mechanism

2.6.5 Advantages of Fluidized Bed Bioreactor

2.7 Literature Review

2.7.1 Manufacturing of biodiesel

2.7.2 Fluidized bed bio-reactor (FBBR)

2.7.3Applications using Biological Fluidized Bed

Chapter 3: Methodology

3.1 Introduction

3.2 Experimental Setup

3.3 SAMPLE TAKEN FOR EXPERIMENTATION

3.4 Acclimatization of biomass

3.5 Experimentation

3.6 Analysis of Samples

3.7 Analysis of reaction rate coefficients:

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Chapter 4: Results and Discussions

4.1 zero order equations

4.2 first order equations

4.3 second order equations

4.4 differential method

4.5 removal percentage graphs

4.2 Analysis of Results and Discussions

Chapter 5: Conclusions

5.1 summary

5.2 conclusions

Chapter 6: References

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CHAPTER 1

INTRODUCTION

1.1 introduction

1.1.1Environmental Engineering

Environmental Engineering is the application of scientific theories and principles to minimize the

impact of human activities on the environment.

Using the principles of biology and chemistry, environmental engineers develop solutions to

Environmental problems. They are involved in water and air pollution control, recycling, waste

disposal, and public health issues.

Environmental engineers conduct hazardous-waste management studies in which they evaluate

the significance of the hazard, offer analysis on treatment and containment, and develop

regulations to prevent mishaps.

They design municipal water supply and industrial wastewater treatment systems. They conduct

research on proposed environmental projects, analyze scientific data, and perform quality control

checks. They provide legal and financial consulting on matters related to the environment.

Environmental engineers are concerned with local and worldwide environmental issues. They

Study and attempt to minimize the effects of acid rain, global warming, automobile emissions,

And ozone depletion. They also are involved in the protection of wildlife.

Many environmental engineers work as consultants, helping their clients to comply with

Regulations and to clean up hazardous sites.

1.1.2INDUSTRIAL WASTES

With the coming of the Industrial Revolution, humans were able to advance further into the 21st

century. Technology developed rapidly, science became advanced and the manufacturing age

came into view. With all of these came one more effect, industrial pollution. Early industries

were small factories that produced smoke as the main pollutant. However, since the number of

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factories were limited and worked only a certain number of hours a day, the levels of pollution

did not grow significantly. But when these factories became full scale industries and

manufacturing units, the issue of industrial pollution started to take on more importance.

Any form of pollution that can trace its immediate source to industrial practices is known as

industrial pollution. Most of the pollution on the planet can be traced back to industries of some

kind. In fact, the issue of industrial pollution has taken on grave importance for agencies trying

to fight against environmental degradation. Nations facing sudden and rapid growth of such

industries are finding it to be a serious problem which has to be brought under control

immediately.

1.1.3 Bio diesel & its effluents

Biodiesel is a domestically produced, renewable fuel that can be manufactured from vegetable

oils, animal fats, or recycled restaurant grease for use in diesel vehicles. Biodiesel's physical

properties are similar to those of petroleum diesel, but it is a cleaner-burning alternative. Using

biodiesel in place of petroleum diesel, especially in older vehicles, can reduce emissions.

Most biodiesel manufacturing processes result in the generation of process wastewaters with free

fatty acids and glycerin (i.e. soapy water). Other constituents in the biodiesel manufacturing

process wastewater include organic residues such as esters, soaps, inorganic acids and salts,

traces of methanol, and residuals from process water softening and treatment.

Sources of wastewater include wash water which is used to remove any soaps formed during the

transesterification reaction; steam condensate; process water softening and treatment to eliminate

calcium and magnesium salts, iron, and copper; and wastewaters from the glycerin refining

process. The typical biodiesel manufacturing wastewater has high concentrations of conventional

pollutants, i.e. biochemical oxygen demand (BOD), total suspended solids (TSS), oil and grease,

and will also contain a variety of non-conventional pollutants.

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1.1.4 Fluidized bed bio reactor

Fluid Bed Reactors have been widely used in Chemical, Bio-Chemical and Petro-Chemical

industries. Theadvantages of Fluid Bed Bio-Reactors (FBBR) are mainly Food, Pharmaceutical

and Biological waste treatment sectors. In a fluidized Bio-Reactor, the particles can be much

smaller and fine. During fluidization operation, the bed expands to accommodate microbial

growth. The high surface area for Biomass to grow results in high heat and mass transfer rates.

This leads to isothermal and uniform mixing of particles tends to high concentration of active

bio-mass per unit volume of reactor.

This process also elimination of pollutants and toxins which are slows down the process. The

problem of cell washout that aggravates operation of continuous, stirred tank fermenters is less

likely in a fluidized bed, indeed it is impossible as long as the superficial liquid velocity is kept

below the settling velocity of the solid particles. Aerobic Reactors require oxygen and depending

upon this they can be classified as two phase or three phase FBBR.

1.1.5 bilogical growth kinetics

The natural process of microbiological metabolism in aquatic environment is capitalized in the

biological treatment of waste water. Under proper environmental conditions, the soluble organic

substances of the waste are completely destroyed by biological oxidation, part of it is oxidized

while rest are converted into biological mass, in the biological reactors. The end products of the

metabolism are either gas or liquid; on the other hand, the synthesised biological mass can

flocculate easily, particularly with increasing mean age of the cells, and are separated out in a

clarifier. Therefore, the biological treatment system usually consists of

(1) a biological reactor, and

(2) a settling tank to remove the produced biomass or sludge.

The application of the above concept of biodegradation in the biological treatment designs,

needs an adequate knowledge of the process kinetics. The following theses try to analyze the

process kinetics through FBBR

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1.2 SCOPE OF THE PROJECT

The studies on industrial waste water treatment have resulted in knowing the different industrial

processes employed to treat wastes, kinetics involved in the biological treatment of industrial

wastes, efficiency and different materials property variance in treatment procedures, modelling

of 3 phased FBBR (fluidized bed bio reactor),cod vs bod removal variance etc

1.3 OBJECTIVES OF THE STUDY

1. The main objective of present study is to estimate treatment efficiency of FBBR

2. COD & BOD removal rates with time of operation and number of days

3. Variance of ph with time of operation

4. Analyzing the biological treatment kinetics & microbiological treatment kinetics

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CHAPTER 2

THEORY AND LITERATURE REVIEW

2.1 INTORDUCTION

The theoretical aspects related to industrial waste water treatment in general ,a literature review

on pilot scale project carried out using FBBR to know the kinetics involved in the reaction etc.,

modelling of the FBBR ,materials used etc. will be presented

2.2 Industrial waste water treatment

Depending on the mode of discharge of the waste and nature of constituents present in it the

treatment may constitute anyone of the following processes

Equalization

Neutralization

Physical treatment

Chemical treatment

Biological treatment

The above processes may be carried out partly or entirely in a municipal sewage treatment or

in separate treatment plant

When the characteristics of the waste water vary in a day also the discharge rate is not

uniform or continuous the waste may require equalization before it is subjected to the

treatment equalization consists of holding the waste water for some pre-determined time in a

continuously mixed basin, which produces an effluent of fairly uniform characteristics

When the waste contains the excessive amounts of acid or alkali (particularly acid) the waste

requires neutralization in the neutralization tank neutralization may be carried out in the

equalization tank, when the conditions permit

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When the industrial waste is treated along with the municipal sewage or both it may be

required to separate the suspended matter by physical operations like sedimentation and

flotation ,sedimentation tanks are to be provided only when the waste contains high amounts

of settablesolids, flotation is employed to separate fine particles with very low settling

characteristics ,flotation consists of creation of fine air bubbles in the waste body by the

introduction of air to the system ,the rising air bubbles attach themselves to the suspended

particles and thereby increase the buoyancy of the particles the particles thus lifted to the

liquid surface are removed by skimming

Some of industrial wastes ,amenable to biological treatment, may require prior chemical

treatment; some requires only chemical treatment without any biological treatment

The chemical and physic-chemical processes treatments involve a significant recurring cost,

and chemical oxidation and precipitation required additional facilities for the treatment of

large quantities of sludge produced, so the chemical treatment should be provided only when

it becomes unavoidable

When the waste substances are biodegradable, with or without acclimatization biological

process is by far the most desirable treatment process .the treatment of an industrial waste

may be accessed by conducting tests on BOD/COD ratio. If the ratio is greater than 0.6,the

wastes are biologically treatable without acclimatization ,if the ratio ranges from 0.3-0.6 the

waste requires acclimatization for biological treatment ;if the ratio is less than 0.3 other

methods are suggested for treatment .the acclimatization involves the gradual exposure of the

waste in increasing concentration to the seed or initial microbiological population under a

controlled condition

The design criteria for the conventional biological treatment processes may be different for

different types of industrial wastes

The system parameters for particular type of industrial wastes may be determined by

laboratory experiments, in absence of any actual test result the performance data of similar

type of waste may be used for design

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In some cases ,while the commonly available microbiological population fails to achieve the

biological oxidation, some special type of microorganisms do well, so for the effective

metabolism of some complex organic substances development of suitable microbial culture

containing specific group of organisms is necessary(as for example some microorganisms

which are phenolytic in action and often in well manured soil have been identified ,and are

employed in activated sludge treatment of coke oven effluents)

Most of industrial effluentsdo not contain sufficient amount of nutrients for good microbial

growth ,for effective biological treatment of this type of waste nutrients are added to the

reactors in the form of urea ,superphosphate or any other compound containing nitrogen

phosphorous ,for balanced growth of microorganisms in the reactor the BOD:N:P ratios of

100:5:1 in aerobic systems and 100:2.5:0.5 in anaerobic systems are to be maintained

Special care should be taken in regard to toxic wastes, toxicity may be of acute or chronic

type and may be humonous plants, animals or to microorganisms responsible for aerobic or

anaerobic biological treatment some of the toxic wastes like phenols, cyanides,

formaldehydes etc. Yield to acclimatized growths of normal or special type of bacteria, some

other toxic metal ions like copper, zinc, chromiumetc. Interfere with the biological oxidation

by taking up the enzymes essentially required for microbial growth, as such these must be

pretreated chemically before the waste is subjected to biological treatment

The selection of particular process depends on the effluent requirements and characteristics

of the wastes, it must be kept in mind that before the treatment policy is fixed up for a

particular industry the scope of recycling and reclamation (recovery)of the wastes must be

considered for a better management of industrial waste waters ,segregation of strong wastes

from the weak wastes sometimes reduces the problem

2.2.1 BIOLOGICAL TREATMENT OF INDUSTRIAL WASTES

Biological treatment is an important and integral part of anywastewater treatment plant that treats

wastewater from either municipality or industry having soluble organic impurities or a mix of the

two types of wastewater sources. The obvious economic advantage, both in terms of capital

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investment and operating costs, of biological treatment over other treatment processes like

chemical oxidation; thermal oxidation etc. has cemented its place in any integrated wastewater

treatment plant.

Biological treatment using aerobic activated sludge process has been in practice for well over a

century. Increasing pressure to meet more stringent discharge standards or not being allowed to

discharge treated effluent has led to implementation of a variety of advanced biological treatment

processes in recent years. The title of this article being very general, it is not possible by any

means to cover all the biological treatment processes. It is recommended that interested readers,

for deeper reading and understanding, refer to well-known reference books e.g. Wastewater

Engineering by Metcalf & Eddy etc. here we briefly discusses the differences between aerobic

and anaerobic biological treatment processes and subsequently focuses on select aerobic

biological treatment processes/technologies

There are two types of biological treatment process; aerobic and anaerobic.

2.2.2 Biological Aerobic Treatment

Biological wastewater treatment is an extremely cost effective and energy efficient system for

the removal of BOD (Biological Oxygen Demand), since only micro-organisms are used. These

feed on the complex materials present in the wastewater and convert them into simpler

substances, preparing the water for further treatment. Aerobic wastewater treatment is a

biological process that takes place in the presence of oxygen. Aerobic wastewater treatment

encourages the growth of naturally-occurring aerobic microorganisms as a means of renovating

wastewater. Such microbes are the engines of wastewater treatment plants. Organic compounds

are high-energy forms of carbon. The oxidation of organic compounds to the low-energy form

(carbon dioxide) is the fuel that powers these engines. Understanding how to mix aerobic

microorganisms, soluble organic compounds and dissolved oxygen for high-rate oxidation of

organic carbon is one of the fundamental tasks of wastewater engineers.

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Since anaerobic treatment is preferred when the dissolved organic concentrations of untreated

wastewater are high, aerobic treatment is often used as a secondary treatment process and

follows an anaerobic stage. Aerobic treatment consists of activated sludge processes or oxidation

lagoons. The size of these can be reduced and tolerance against fluctuations and toxics increased

by adding a step with moving bed bioreactors (MBBR) prior to the active sludge treatment.

Advantages are

1) Energy efficient

2) Cost effective

3) Can be used in combination with anaerobic processes

2.2.3 Biological Anaerobic Treatment

Anaerobic wastewater treatment is the biological treatment of wastewater without the use of air

or elemental oxygen. Many applications are directed towards the removal of organic pollution in

wastewater, slurries and sludges. The organic pollutants are converted by anaerobic

microorganisms to a gas containing methane and carbon dioxide, known as "biogas". Anaerobic

treatment is a slow process and can take up to 3 months, also due to septic decomposition,

unpleasant odours may occur

2.3 BASIC TYPES OF REACTORS

Wastewater involving physical, chemical and biological unit processes is carried out in vessels or

tanks commonly known as reactors. Reactors are used for growing cells. Reactors are designed

to meet the specific needs of the cells viz., optimal mixing, optimal temperature, and optimal pH.

In certain cases, reactors continuously supply nutrients or precursors to produce a particular

product. Reactors are available in a number of designs. Various types of reactors used for the

treatment of wastewater are as follows:

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1. Batch Reactors: In the batch reactor, flow neither enters nor leaves the reactor

continuously. The liquid contents of the reactor are mixed completely. Batch reactors are

often used to blend chemicals or to dilute concentrated chemicals.

2. Complete-Mix Reactors: In the complete-mix reactor, it is assumed that complete mixing

occurs instantaneously and uniformly throughout the reactor as fluid particles enter the

reactor. Fluid particles leave the reactor in proportion to their statistical population.

Complete mixing can be accomplished in round or square reactors if the contents of the

reactor are uniformly and continuously redistributed. The actual time required to achieve

completely mixed conditions will depend on the reactor geometry and the power input.

3. Plug-Flow Reactors: Fluid particles pass through the reactor with little or no longitudinal

mixing and exit from the reactor in the same sequence in which they entered. The

particles retain their identity and remain in the reactor for a time equal to the theoretical

detention time. This type of flow is approximated in long open tanks with a high length-

to-width ratio in which longitudinal dispersion is minimal or absent or closed tubular

reactors.

2.4 basic kinetic equations

Whenever a micro-organism is inoculated in a suitable substrate it grows' in number by

multiplication, and the process of growth continues till the substrate is exhausted or any other

factor hinders the growth. In a batch reactor such growth of micro-organ may be schematically

shown as in Fig. The growth pattern follows three distinct phases

(1) log or exponential growth phase,

(2) declining or retarded growth phase, and

(3) endogenous growth phase or death phase

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in the log growth phase ,the supply of the substrate is always adequate and the rate of

metabolism is only dependent on the ability of the micro-organism to utilize the substrate. In the

declining growth phase the rate of metabolism decreases due to the limitations in substrate

supply. In the endogenous growth phase, the micro-organisms are forced to oxidize their own

protoplasms for energy (endogenous respiration) and thereby decrease in number. The growth

pattern as shown in above figure is not applicable in a continuous biological reactor, where the

substrate or food for the micro-organism is continuously supplied.

The rate of substrate supply and the mass of active micro-organisms set the growth phase of

micro-organisms or the rate of metabolism in such a reactor. In other words, the "Food-to-micro-

organism" ratio controls the rate of metabolism in a continuous biological reactor, as shown in

Fig2.

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Low food-to-micro-organism ratio, i.e. relatively scanty supply of food results in an endogenous

growth of micro-organisms; on the other hand log growth phase of metabolism is observed when

the supply of food is abundant, i.e. when the food-to-micro-organism ratio is higher. The sludge

produced at log phase is of very poor settling characteristics, and that in the endogenous phase

not only settles well but it is also more stable in nature. As such, in all biological reactors, the

system is so adjusted as to create a rate of metabolism ranging in between endogenous and

declining growth phase, as shown in Fig2.

As evident from Fig1, the formulation of a biological process is possible either in terms of

changes in the substrate concentration or in terms of microbiological growth. In the analyses and

design of a biological treatment system, any such formulations can relied upon, depending on

the availability of relevant data. However the microbiological growth kinetics offer a more

rational method designing the biological treatment units.

2.4.1 Biological-Treatment Kinetics

Kinetics Normally the biological treatment units are operated in declining growth phase of the

micro-organisms. At decli growth phase, the BOD removal rates are observed to concentration

dependent, and are expressed by the followi relationship

-dS/dt =KS

Where

S=amount of BOD remaining in the reactor after time t, mg/ltr

t=contact time(days)

k=1st order BOD removal constant, per day( T-1)

it may be noted that the va;lue of K may be based on either overall BOD5 or only soluble BOD5

soluble BOD5 removal rate constants are always higher than the overall BOD5 removal rate constants.

The value of K may vary with different types of wastes and environmental conditions. But for

normal domestic waste it may be assumed to be equal to 0.23/day

Integration of the Eqn. 3.1 between the limits S = So at t = 0, and S = S1 at t = t yields:

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S1/S0 =e-kt

in which So = initial concentration of BOD and S1 = final concentration of BOD

The Eqn is a normal 1st order BOD removal rate equation and is applicable for a batch operation

only. The Eqn is sometimes written in the following form, which takes into account of the mass

of micro-organisms in the batch reactor:

-dS /dt = kXS

in which

k = specific BOD (overall or soluble, as the case may be) removal coefficient, 1/mg/day, which

equals to K/X, and

X= micro-organism concentration in the reactor, mg/l.

In most of the biological reactor designs, the concentration of the volatile suspended solids

(VSS) in the reactor is taken as the ncentration of the microbial mass. This assumption is true

only when the waste under treatment is soluble in nature; but the timate with such assumption

may be two fold to five fold in an Chic treatment, and upto two fold in anaerobic treatment, with

mestic waste water, because of a large amount of inactive (i.e. n-biomass) volatile suspended

solids present in it. However, since y the settled waste waters are treated, in most of the

biological tment units, the above approximation may not give rise to an ratifiable error. The

value of k and K are generally reported for a standard 'tor temperature of 20C. These values at

other temperatures y be calculated using the following relationship.

KT=k20T-20

in which

T = temperature in C, and

= temperature coefficient.

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Different values of 0 have been reported by different workers for different temperature ranges.

Unless otherwise stated, for temperatures not below 20C, 0 may be assumed as 1.047, batch

processes. In continuous flow biological reactors, howev the following values may be assumed

for

1) Activated Sludge Process 1.00-1.03

2) Trickling Filter 1.02-1.04

3) Aerated Lagoon 1.06-1.09

2.4.2 Microbiological Growth Kinetics:

In any low-substrate-concentration system, under pro environmental conditions, the mass of

micro-organisms will tend increase due to cell synthesis and decrease due to the endogeno

respiration; the net rate of growth of bio-mass, dX/dt, may given by the following relationship:

in which

dX/dt = Y dF/dt kdX

X = concentration of the micro-organisms in the actor, mg/1 (ML-3),

t = time of contact in the reactor, days (T),

dX/dt = growth of micro-organisms in unit time per volume, (ML-3 T-1), mg/1 /day.

dF/ dt = rate of substrate utilization, mgfl/day (ML-3

Y = growth yield coefficient, mg/mg, and

kd = micro-organism decay coefficient, per day, (T-1)

Now, if S is the concentration of a soluble substrate in reactor, for a normal biological reactor,

where the subs removal is mediated through the micro-organisms only, the rate reduction of

substrate concentration can closely be approximated to the rate of substrate utilization

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=

The equation can be rewritten as

(dX/dt)/X= dF/dt/X = -kd

the term (dX/dt)/X is referred, to as the "specific growth rate" and is often symbolized as 1.1, and

the term dF/dt/X is referred to as the "specific substrate utilization rate". Now in a batch process,

if the substrate is supplied to the micro-organisms in excess, the specific substrate utilization rate

remains constant under a particular set of substrate type, micro-organisms, and environmental

conditions. However, when the concentration of the substrate becomes growth limiting, i.e. when

the substrate supply falls short, the specific utilization and hence specific growth of micro-

organism declines. The relationship between the substrate concentration and the specific

substrate utilization rate is usually given by the following continuous hyperbolic function and is

shown graphically in fig3.

/

=

+ =

/

In Which

km = maximum rate of specific substrate utilization, per day (T-1),

Ks = substrate concentration at the utilization rate of km/2, mg/1 (ML-3)

Now in normal biological reactors where the substrate concentration is usually low, i.e. S < Ks,

the specific utilization rate approaches to km S/Ks,

/

=

=

/

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=

For any general case the equation may be rewritten as follows

/

=

+

2.5 Fluidization

Fluidization is a process in which solids are caused to behave like a fluid byblowing gas or liquid

upwards through the solid-filled reactor. Fluidization is widely used in commercial operations;

the applications can be roughly divided into two categories

physical operations, such as transportation, heating, absorption, mixing of fine powder,

etc. and

chemical operations, such as reactions of gases on solid catalysts and reactions of solids

with gases etc.

The fluidized bed is one of the best known contacting methods used in the processing industry,

for instance in oil refinery plants. Among its chief advantages are that the particles are well

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mixed leading to low temperature gradients, they are suitable for both small and large scale

operations and they allow continuous processing. There are many well established operations

that utilize this technology, including cracking and reforming of hydrocarbons, coal

carbonization and gasification, ore roasting, Fisher-Tropsch synthesis, coking, aluminum

production,melamine production, and coating preparations. The application of fluidization is also

well recognized in nuclear engineering as a unit operation for example, in uranium extraction,

nuclear fuel fabrication, reprocessing of fuel and waste disposal.

2.6 FBBR(fluidized bed bio reactor)

fluid Bed Reactors have been widely used in Chemical, Bio-Chemical and Petro-Chemical

industries. The advantages of Fluid Bed Bio-Reactors (FBBR) are mainly Food, Pharmaceutical

and Biological waste treatment sectors. In a fluidized Bio-Reactor, the particles can be much

smaller and fine. During fluidization operation, the bed expands to accommodate microbial

growth. The high surface area for biomass to grow results in high heat and mass transfer rates.

This leads to isothermal and uniform mixing of particles tends to high concentration of active

bio-mass per unit volume of reactor.

In the present experiment it can be described as a technique of biological treatment of

wastewater that can be used to carry out a variety of multiphase biochemical reactions. The

fluidized bed bioreactor is similar to the packed bed reactor in many respects, but the packing

material is expanded by the upward movement of fluid through the bed. The expanded porosity

of the fluidized bed packing material can be varied by controlling the flow rate of the fluid. The

fluidized media provides an extremely large surface area on which a film of microorganisms can

grow and produce a large inventory of biomass in a small rector volume. The result of this

biological growth is a system capable of high degradative performance for target contaminants in

a relatively small and economical reactor volume.

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2.6.1PRINCIPLE:

The solid substrate material in the fluidized bed bioreactor is typically supported by a porous

plate, known as distributor. The fluid is then forced through the distributor up through the solid

material. At lower fluid velocities, the solids remain in place as the fluid passes through the voids

in the material. This is known as a packed bed reactor. As the fluid velocity is increased, the

reactor will reach a stage where the force of the fluid on the solids is enough to balance the

weight of the solid material.

This stage is known as incipient fluidization and occurs at this minimum fluidization velocity.

Once this minimum velocity is surpassed, the contents of the reactor bed begin to expand and

swirl around much like an agitated tank. The reactor now becomes a fluidized bed bioreactor.

2.6.2 CONSTRUCTION FEATURES:

The fluidized bed bioreactor is simple in design containing provision for distribution of the

influent liquid flow and a component to control the expansion of the fluidized bed when

necessary. When biological growth occurs on the particles of fluidized bed media, the diameter

of the particles increases and their effective density is reduced, resulting in a bed expansion

beyond that experienced with unseeded media. Under conditions resulting in extensive biofilm

growth, it may be necessary to control the biofilm thickness to prevent the density of the biofilm

covered media from decreasing to the point where bed carryover occurs

2.6.3 MECHANISM:

The fluidized bed bioreactor is a fixed-film reactor column that fosters the growth of

microorganisms on a hydraulically fluidized bed of media. In this reactor the liquid to be treated

is pumped upwards through a column bed of small biofilm coated particles at a flow rate

sufficient to cause fluidization of bed i.e., a state in which the particles, though retained within

the reactor, are able to move relative to one another in the liquid rather than being sedimented

and immobile. In fluidized bed bioreactors, it is possible to achieve a high concentration of

biomass depending on the operational conditions used in the process and the type of support used

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to immobilize the microorganisms, which are found within a complex structure of cells and their

extra cellular products, referred to as a biofilm. Inorder to achieve aerobic degradation in this

reactor, support particles are fluidized by the flowing wastewater, which must have been

previously oxygenated or flow co-currently together with an air stream. Fluidization also allows

a greater volume of waste to be treated in the reactor per unit time, because greater flow rates

may easily be used with insignificant head losses.

2.6.4 FACTORS AFFECTING MECHANISM:

Performance of fluidized bed bioreactors greatly depends on the amount of biomass attached to

the inert core support particles and overall bed voidage. Thus, for proper design of an FBBR, it is

important to know the biological particle mixing and bed expansion behaviour, which inturn,

influence bed volume and consequently the residence time of the liquid phase.

Fluidization of the medium increases the effective surface area, compared with that of packed

beds. With packed beds, bridging tends to reduce the effective surface area, and comparable

contaminant loadings cannot be expected. When the fluidized bed bioreactor is used, the entire

surface area of the bed particles becomes available as biologically reactive sites because there is

no contact between particles. In fluidized bed bioreactors, effluent recirculation is necessary to

provide the fluid velocity within the necessary treatment detention times. Performance of the

reactor is normally site specific and depends on ambient conditions, type and quality of the

wastewater and nitrate and dissolved oxygen concentrations etc.

2.6.5 ADVANTAGES OF FLUIDIZED BED BIOREACTOR

FBBR has various advantages. Some of them are listed below.

1. As the media on which microorganisms grow is influidized state, the surface of the media

available for the development of microorganisms is quite large which leads to high concentration

of microorganisms and thus high flow rate can be achieved in FBBR.

27 | P a g e

2. Because of large concentration of microorganisms, FBBR bears high potential for the removal

of various parameters such as BOD, COD, nitrogen, etc.

3. Size of the FBBR plant is small as compared to other types of the reactors and hence the space

requirement

4. FBBR is capable of accepting shock loads.

5. Treatment by FBBR is economical where land cost is high.

6. If FBBR is operated properly, there is no need to provide secondary setting tank, which leads

to a saving in the total cost of plant.

7. FBBR provides an extraordinarily long SRT for microorganisms necessary to degrade the

xenobiotic and toxic compounds.

8. The system operation is simple and reliable

2.7 LITERATURE REVIEW

2.7.1 Manufacturing of biodiesel

Biodiesel has become an integral part of the discussion of renewable energy sources This paper

will consider used food oil as a fuel source at Williams College with a specific focus on the

feasibility of either manufactured biodiesel or waste vegetable oil (WVO) as replacements or

supplements for petroleum-based fuel Both WVO and biodiesel have potential for use on the

Williams campus, though their applicability to the school depends on future trends in vehicle

usage and fleet replacement. Despite this relative uncertainty, there is a definite place for used

cooking oil at Williams and the precedent set by other institutions of higher learning should

serve as a model for the colleges future plans.Biodiesel and waste vegetable oil are both

produced or refined from used vegetable oil, though each with different degrees of difficulty and

involvement. Biodiesel can be used in diesel-fueled vehicles without any modification of the

engine. Additionally, biodiesel can be mixed with petroleum diesel to create different grades of

fuel that are labeled based on the percentage of biodiesel in the blend; for example, B10 is 10%

28 | P a g e

biodiesel, 90% petroleum diesel. This means that in times of biodiesel scarcity, vehicles can use

a mix of fuels and still function the same way.

Though biodiesel has advantages in terms of its flexibility and applicability, the processto create

it is more complicated than WVO. Biodiesel is created from animal or vegetable oil that is

modified through a process called transesterification, during which triglycerides in the oil are

converted to methyl and ethyl esters and glycerin. First, the used vegetable oil must be filtered

for food scraps and solid waste particles. The oil is then heated to remove water and titration

must be performed to determine how much sodium hydroxide (NaOH) and methanol catalyst is

needed. A mixture of NaOH and methanol is then mixed in to the waste oil. The NaOH can be

procured in the form of lye drain cleaner while methanol is commonly found as gas tank

antifreeze. The glycerin that is produced must be removed through a process of washing and

drying before the biodiesel can be used as a fuel.

In comparison, waste vegetable oil production is much easier, though its applicability to vehicles

is dependent on the conversion of the existing diesel engine. The process of creating WVO is

incredibly simple: collect the used vegetable oil and filter the particles out of it. Modifying a

diesel vehicle to run on vegetable oil requires the addition of an additional tank to contain the

WVO and the installation of apparatus that allows the burning of both diesel and vegetable oil in

parallel. Conversion kits for vehicles are readily available, though the models they are designed

for are limited in number. A vehicle cannot run on WVO alone; it must start and stop on diesel

because the engine has to be warmed up and the oil must be heated before use.

As a result, WVO is not ideal for use over short distances, especially with intermittent turning on

and off of the engine as this would defeat the purpose of using the waste oil. Both biodiesel and

WVO present significant benefits in terms of ease of acquisition and emissions reductions. Waste

food oil can be obtained from any restaurant or dining hall that uses vegetable oil for frying food;

generally this waste oil is either disposed of or given away, so there is no cost to obtaining this

fuel source. Regarding emissions, biodiesel is the only alternative fuel source to have completed

the EPAs Tier I and Tier II health effects testing under the Clean Air Act. These tests

demonstrated significant reduction of nearly all regulated emissions and showed

biodiesel does not pose a threat to human health. Additionally, a U.S. Department of Energy

study showed that the production and use of biodiesel, compared to petroleum diesel, resulted ina

29 | P a g e

78.5% reduction in carbon dioxide emissions (Benefits of Biodiesel, 2009). Waste vegetable oil

has been found to reduce the amount of particulate matter, hydrocarbons, and carbon monoxide

in exhaust without any significant increase in the amount of nitrogen oxide produced (Wilson

and Vojtisek-Lom, 2004). Performance and fuel economy for both biodiesel and WVO is

roughly equivalent to petroleum diesel, though the use of high percentage biodiesel blends can

impact fuel system components in older vehicles, primarily fuel hoses and fuel pump seals that

contain elastomeric compounds that are incompatible with biodiesel (Biodiesel Performance,

2007). Despite this concern over degradation of parts, the Magnuson-Moss Warranty Act, passed

by Congress in 1975, prohibits auto manufacturers from refusing to honor a warranty if their

product has a problem not directly caused by burning biodiesel. In general, most companies will

explicitly warranty blends of biodiesel ranging from five to twenty percent. The use of WVO, on

the other hand, voids the majority of warranties because it involves the actual conversion of the

fuel system. The consideration of manufacturers recognizing warranties is more of a concern

with the WVO-fueled vehicles since they are a more recent and experimental phenomenon at this

stage.

2.7.2 Fluidized bed bio-reactor(FBBR)

The biological fluidized bed reactor uses the biofilm which covered on carrier surface and bring

into play its function. Among these available different processes (such as: activated sludge

process, trickling filters, biodisc, etc.) to create efficient contacts between phases, fluidized bed

bioreactor (FBBR) seems to be the best one and present many advantages relating to

hydrodynamics and mass transfer phenomena.The use of fluidization as a contact technique in

biotechnology field gained considerable importance.

In biological fluidized bed, the small size particle provided the surface area where the

microorganism can adhere, roost and grow greatly, and in reactor keeps high microorganism

density

30 | P a g e

The fluidization operating mode create the effective mass transfer condition in reactor, according

to oxygen or mass transmission speed enhances obviously, the oxygen utilization is efficient as

well. High biomass and significant mass transfer condition enable the biological fluidized bed to

be possible to maintenance effect and reduce the reactor volume, consequently save the plant

investment. Compared the activated sludge process, the biological fluidized bed has the strong

anti-impact load capability, has does not the sludge expanded. Wei C. H. (1989) considered that

the Fluidized bed was with the great cubage loading () and sludge loading () its is 13 times

of conventional activated sludge system, 10 times of stage-aeration and 38 times of Bio filter.

In order to prevent the carrier escape, generally in reactor supposes the bufferzone, and the

biofilm which falls off may separate in buffer zone. When the loading is weak and the discharge

standard of suspended solid density is not special, second settling pond should be omitted, and

the process is simplified. As a result of the gas perturbation in three-phase fluidized bed, the

biofilm renews quickly with high activeness, and the membrane escape equipment need not be

installed as possibility. So far, the biological fluidized bed was employed in organic wastewater

treatment had approximately 30 years histories, and the varied structures were innovated.

However, the numerous researchers are inconsistent to the classification of the biological

fluidized bed.

Several typical kinds are described as following:

1. Conventional Biological Fluidized Bed

A. Two-phase biological fluidized bed

The typical two-phase fluidized beds are shown in Figure 5a,b, the fluidization power originates

from the extra circulating pump, in fluidized bed the carrier pellets expand and the fluidization

under the hydrodynamic function. Among them, Figure 5a is anaerobic fluidized bed, Figure 5b

is aerobic fluidized bed, the aerobic process needs the wastewater which aerated outside, then

feeds in fluidized bed. The merits of two-phase biological fluidized bed including: high handling

capability, no jamming problem, strong anti-impact load capability, compact structure, etc.. But

the disadvantages still existed: control difficultly for the expansion and biofilm thickness; in

aerobic stage the high capability aerator is absolutely necessarily.

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B. Three-phase biological fluidized bed

The traditional three-phase biological fluidized bed can solve two-phase fluidized bed pre-

aeration difficultly, reduce the energy consumption. Through the air bubble perturbation, further

strengthened between the liquid-solid mass transfer effect, and may control the biofilm thickness

to a certain extent by hydrodynamic shearing force (see Figure 5c.)

2. Nevel Biological Fluidized Bed Reactor

Along with the wastewater process technology unceasing development, highly effective, the low

consumption and treat to the organics waste water which degrade difficultly is one biological

fluidized bed development direction. Introduces several kinds in the last few years appear new

biological fluidized bed reactor as follow:

A. Circulation biological half fluidized bed

The Beijing chemical industry institute developed a novel half fluidized bed (see Figure 5d). The

circulation biological half fluidized bed realized the fluidized bed and the fixed bed series

operation, it not only had the good circulation characteristics, moreover overcame the difficulty

of the low removal efficiency for degrade difficultly organics in mixing reaction. Treated with

the starch wastewater, the hydraulic resident time (HRT) is shorter than 4h, COD load is 4.2kg/m

3 d, the least liquid/gas rate is

B. Oxygenation internal recycling three-phase compound biological fluidized bed

Based on the compound biological fluidized bed, the North China engineering institute chemical

industry innovated the structure which is made up of three-phase fluidized bed at bottom, at top

has safety filters and padding, the effluent through the oxygenation system, then enter the

contacted oxygenation bed with further reaction. Composed concurrently with the fluidized bed

and filter bed, the pilot is provided with small energy consumption, great compatibility, low

liquid/gas rate, the application prospect will be widely.(see Figure 5e)

C. BASE three-phase biological fluidized bed reactor

This kind of reactor was increased one catheter (anoxia area) in original BAS, obtained the

enough resident time and created the anoxia condition, NH3-N removal could be achieve

32 | P a g e

effectively. Adjusted the barometric pressure of aerobic area and minor loop hole of aerobic-

anoxic sector at the base which can be controlled the liquid and biofilm circulation in two

sectors, therefore does not need add the pump and the circulate pipeline.

D. The new Circox airlift three-phase fluidized bed reactor

This kind of fluidized bed was added one anaerobic area in traditional fluidized bed, the

denitrifying ability was enhanced. Due to the reactor has the aeration and anaerobic area, the

mixing uniformity and higher liquid speed can be obtained. The Circox airlift fluidized bed was

used in potato wastewater anaerobic pretreatment, and COD removal rate was high, its volume

loading may meet 4-10kg/ m 3 d, the denitrify rate up to 90%, the biomass in bed achieved as

high as 30g/L, the surplus sludge rate only has 2%-10%.

E. Internal-loop fluidized bed

The reactor consists of a three-phase (biofilm particles, water and air)internal-loop airlift reactor

(see Figure 5h) for nitrification, which is extended with a two-phase (biofilm particles and water)

external concentric downflowing bed, the extension for denitrification. As a result of the special

design of reactor, the liquid velocity in extension can be manipulated by the overpressure in the

headspace of aerobic compartment, thus controlling the liquid recirculation ratio between the

aerobic compartment and extension.

F. Triplet loop fluidized bed

Hydrodynamics and mass transfer of triplet loop biological fluidized bed reactors (see Figure 5i)

were studied in terms of gas holdup,liquid circulation velocity and volumetric mass transfer

coefficient It was bound from experiments that the main factor affecting hydrodynamics and

mass transfer is gas holdup. Liquid circulation velocity decreases with increase in the gas

holdup,whereas volumetric mass transfer coefficient increases with it ,Compared with

performance in conventional loop reactor,the gas holdup in triplet loop reactor increases by ten

to fifteen percent, and volumetric mass transfer coefficient in triplet loop reactor Increases by

over ten percent.

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G. the extra-circulation three-phase biological fluidized bed

The fluidized bed is made of Plexiglass and shown schematically in Figure 5j, which consists of

a main bed and an auxiliary bed. The inside diameter and height of the main bed are 100 mm and

970 mm, while that of the auxiliary bed are 200 mm and 770 mm. The total volume of the

fluidized bed is 38 L. Granular activated carbon (40~60mech, 1160kg/m 3 ) is chosen as the

microorganism carrier. The transformation between aerobic and anoxic state in reactor is

facilitated by an automatic control box. It is demonstrated that COD removal efficiency kept

80% as HRT longer than 4 h in reactor

34 | P a g e

CHAPTER 3

METHADOLOGY

3.1 Introduction

Here we deal with information regarding fabrication of experimental setup, preparation of stock

solutions, biomass acclimatization, experimental program and analysis of samples

3.2 Experimental setup

A laboratory scale FBBR is constructed for experimental purpose using 6mm thick acrylic tube

,the setup consisted of 3 acrylic tubes of 1200mm height with 69mm internal dia and 75mm

external dia each arranged parallel to each other with valves at top and bottom of the tubes to

regulate the flow through them, to ease the experimentation and to keep the setup intact the

plates are provided at top and bottom of the tubes on which the experimental tubes rest and the

mesh is provided between the plates so as to prevent the loss of bed material into the pipe, the

sample water from waste water reservoir is pumped in to the 1inch dia pipe which carry the

water to the tubes whose valve is opened through the mesh which is placed between the plates

and the treatment is carried by fluidized bed in the tube and the water again goes thought the

mesh which is present at the top of the tube in between plates and goes to the outlet pipe fro

which the water is collected ,a flow meter is also arranged on inlet pipe to measure rate of flow,

flexible pipes of 1 inch dia are used as inlet and outlet pipes,plates acts are transition zone

between the inlet pipes of 1 inch dia and acrylic tubes of 69mm dia ,air is also blowed into the

tube through the pipe so as to make Shure that aerobic reaction takes place, air is blowed in to

the pipe from air condense through valve which is present in between the first tube and flow

meter ,and the air pressure is also regulated using the meter present or the amount of air flown to

the pipe is regulated by meter attached to condenser, and the 3 different bed materials are

introduced to the 3 tubes taken for experimentation, materials introduced in to the columns are

bio carriers also called MBBR media, pumicestones, Foam the experimental setup is shown in

the figure

35 | P a g e

1

2

3

4

5

6

7

Fig.3.2 Laboratory Setup of Fluidized Bed Bioreactor

(1)Valves (2) Stainless Steel Mesh (3) Perspex column of length 120 cm

(4) Air compressor (5) 2.5 HP Motor (6) stock solution (7) Flow meter

36 | P a g e

37 | P a g e

Fig 3.2 Bioreactor in operating condition with different bed materials

38 | P a g e

3.3 SAMPLE TAKEN FOR EXPERIMENTATION

The effluent water from the local food processing industry and bio diesel plant is taken at 15ltrs

each per day and diluted to 1:2 and 1:4 concentrations respectively for experimentation, the COD

& BOD values of the effluents are calculated before the experiment and after the dilution also

3.4 ACCLAMATIZATION OF BIOMASS

A 5ltr capacity plastic jar with open top was used for biomass acclimatization which is microbial

growth ,a concentrated solution is prepared by crushing tomatos in the jar and mixing with small

amount of waterv and adding both wet and dry sludge collected from domestic sewage plant to it

making over to 4ltr of the jar ,and ingratians are mixed thoroughly daily for aerobic growth of

microoganisms ,the process is contined for a week and the slurry which is obtained at the end in

the jar is introduced 1 ltr each in to the tubes which acts as seed for biomass acclimatization for

bed particles in the tubes

3.5 EXPERIMENTATION

The acclimatized biomass is transferred to the acrylic tubes and aerated by by filling the tube

with water for 3 days before the start of experiment, then the experiment is started by pumping

the effluent taken from the industry and diluting it to required concentration as said and recycling

it ,the COD of the effluent before pumping is measured and also durig the experimentation the

sample from outlet is taken at intervals of 30min,60min,90 min and the respective COD & BOD

values are measured, simultaneously the rate of flow is measured in the gauge and also rate of

flow is measured at outlet pipe through which water goes to the effluent reservoir the same is

carried out in other two tubes with different bed materials, the process is continued till the

constant percentage removal is obtained from the treated water

3.6 ANALYSIS OF SAMPLES

The influent and effluent samples were analyzed for COD & BOD values using standard

methods.

The COD of the sample is measured by standard reflux method ,The principle governing

standard reflux method is as follows: Many types of organic matter are oxidized by a boiling

39 | P a g e

mixture of chromic and sulphuric acids. A sample is refluxed in strongly acidic solution with a

known excess of potassium dichromate (K2Cr2O7). After digestion, the remaining unreduced

K2Cr2O7 is titrated with ferrous ammonium sulphate to determine the amount of K2Cr2O7

consumed and the oxidizable matter is calculated in terms of oxygen equivalent. The equipment

and the reagents used for the analysis of samples are reflux apparatus. Standard potassium

dichromate solution, concentrated sulphuric acid with silver sulphate crystals, ferrion indicator

solution, standard ferrous ammonium sulphate and mercuric sulphate, HgSo4 powder.

The procedure used for the determination of COD is as follows: 20 ml of sample was taken into a

round-bottomed flask and 20 ml of distilled was taken into another flask. To each of the two

flasks, 0.4 gm of HgSo4 and 10 ml of potassium dichromate solution were added carefully and

by mixing 20 ml of sulphuric acid. Glass beads were also added. The flasks were attached to the

condensers and were kept in the reflux for 2 hours. After 2 hours of boiling, the condensers were

cooled and rinsed with distilled water. The reflux condenser was disconnected and diluted to

about twice its volume with distilled water. 2 to 3 drops of ferrion indicatorsolution was added to

each of the flasks and titrated against ferrous ammonium sulphate to the endpoint when the

colour changes sharply from bluish green to reddish brown. The initial and final burette readings

were noted.

COD as mg/lit = (A-B)*M*8000/m1 of sample.

Where

A = ferrous ammonium sulphate used for blank (ml)

B = ferrous ammonium sulphate used for sample (m1)

M = molarity of ferrous ammonium sulphate, and

8000 = milliequivalent weight of oxygen* 1000 m1/1.

The removal efficiencies at each operating time were calculated and tabulated. The variation of

treatment efficiencies against the time are plotted at 30, 60, and 90 minutes of treatment times

The bod of the sample is measured based on microorganisms in the wastewater to decompose

waste. These microorganisms are primarily aerobic, so they use up oxygen as they break down

40 | P a g e

organic matter. The Biochemical Oxygen Demand, or BOD, is the amount of dissolved oxygen

which is used up by these microorganisms and is roughly equivalent to the amount of "food"

(organic matter) found in the wastewater. The more "food" that is present in the water, the more

DO will be used up by the bacteria and the greater the BOD reading will be.

A major disadvantage of the BOD test is that results are not available for 5 days. Nevertheless,

BOD tests are an integral part of the wastewater operator's repertoire. Wastewater treatment

plants use BOD as an estimate of the waste load in the influent water. BOD tests are used to

determine the effects of discharges on receiving waters.

The procedure used for the determination of BOD is as follows:Take 300 mL sample in BOD

bottle. Prepare two sets of this sample. Keep one set for DO analysis for day 0 (i.e.,

Sample0Day) and another sample in BOD incubator for 5 days at 20 C (Sample5Day) (this is

how 5-day BOD experiment is done). Here you will prepare duplicate samples and analyze at

Day 0 (i.e., Sample0Day_A and Sample0Day_B). For a given sample bottle, add 1 mL of alkali

azide and then 1 mL manganous sulfate solution. Shake well the bottle and keep it open for 5

minutes to settle the precipitate. Add 2 mL concentrated H 2 SO 4 and place the cap on the

bottle. Shake well the bottle till all the precipitate is dissolved. Take 203 mL of sample in conical

flask and titrate with standard sodium thiosulfate solution (0.025N) till the colour changes from

dark yellow to light yellow. Then add few drops of starch indicator and continue to titrate till the

color of the solution becomes either colorless or changes to its original sample colour. Note

down volume of 0.025N sodium thiosulfate consumed. Calculate DO value of the sample.

Remember that in 200 mL sample, 1 mL of sodium thiosulfate of 0.025N equals to 1 mg/L

dissolved oxygen

Dissolved oxygen (DO) (in mg/L) = mL of sodium thiosulfate (0.025N) consumed.

BOD = (initial D.O final D.O-blank correction) X Volume of diluted sample

Volume of sample taken

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3.7 Analysis of reaction rate coefficients:

Typically, reaction rate coefficients are determined using the results obtained from batch

experiments, from continuous-flow experiments, and from pilot and fields-scale experiments.

Using the data from experiments, the coefficients can be determined using a variety of method

including

(1) The method of integration and

(2) The differential method

As summarized in the method of integration involves the substitution of the measured date on

the amount of reactant remaining at various times into the integrated form of the rate expression.

Plots of the integrated forms of the reaction rate expressions used to determine the reaction rate

coefficients are as follows

Zero order reaction :

rc= dc/dt = k

k determined by plotting graphically c versus t

first order reaction :

rc= dc/dt = kc

k determined by plotting graphically ln(c/c0) versus t

second order reaction :

rc= dc/dt = kc2

k determined by plotting graphically 1/c versus t

42 | P a g e

in the deferential method, where the order of the reaction is unknown, the concentrations remaining

at two different times are used to solve the differential form of the rate expression for the order

of the reaction. Once the reaction order is known, the reaction rate coefficient is determined by

substitution using the test data.

rc= dc/dt = kcn

k determined by plotting graphically log(dc/dt) versus log(c) or analytically by solving for n

The application of these two methods is illustrated in our experiments.

3.8 Biological Treatment Kinetics, as Applied in Continuous Reactor

Assuming that the removal of BOD is governed by a 1st order equation , the material balance in

a complete-mix reactor may be written as follows.

[Rate of change of BOD in the reactor] = [Rate of BOD inflow] - [Rate of BOD outflow]- [Rate

of BOD removal]

or, (dS/dt)V =QS0 QS1 KS1V

in which,

Q = waste flow rate,

V = volume of the reactor,

So = influent BOD (Substrate) concentration,

S1 = effluent BOD concentration, and,

43 | P a g e

K = 1st order BOD removal rate constant,

Now in steady state, dS/dt = 0.

From the above equation we get 1

0 =

1

1+(

)

3.9 Microbiological Growth Kinetics, as Applied in Continuous Reactor

In the analysis of these type of biological reactor, the following assumptions are made:

(i) Liquid waste flow into the reactor at a constant rate Q, is instantaneously and

homogenously mixed with the contents of the reactor.

(ii) The mixed liquor of the reactor is withdrawn at a rate equal to the rate of inflow Q,

(iii) Influent does not contain any active microorganisms, and

(iv) The microorganism concentration in the effluent and that the reactor are equal.

Under these conditions, the material mass balance across the system may be written as

follows:

[Rate of change biomass in reactor] = [Net growth rate of microbial mass in the reactor.] =[Rate

of microorganisms outflow from the reactor ]

(dX/dt) V =(Y dF/dt - kdX)V - QX

44 | P a g e

But as in a steady state, the microbial mass reaches a constant value,

dX/dt=0 dt

the eqn. reduces to:

(Y (df/dt) kdX)V = Qx

Now, the mean retention time of the microbial mass in the actor, or "mean cell residence

time"c, is given by:

c =VX/QX =V/Q=

it which,

= hydraulic retention time,

c, = mean cell residence time.

using above Eqn may be rewritten as follows:

1/ c =Y (dF/dt)/X -kd

I he specific substrate utilization rate, (dF/dt)/X represents the food to-micro-organisms ratio",

U, or, the "process loading rate, when considered on a finite mass and time basis.

U =(AF/At)/XM

I which F/ t = amount of food utilized "per unit time of t,

Xm = mass of the active micro-organisms in the reactor. Using above Eqns., reduces to the

following form:

1/ c = Y.U kd

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The above Eqn. 3.20 is the basic or the controlling equation in any biological reactor of this type.

Hence the process can be controlled by regulating either c , or U.

solving all Eqn. for the effluent substrate concentration, S1, the following relationship is

obtained:

1 =(1+c)

c (YKmKd)1

The Eqn completely defines the value of the effluen substrate concentration S1 which is our Ceff,

for a particular type of substrate with characteristic values of km, KS, Y and kd, and for a given

value of control process parameter, c

As the above equation is used for steady state condition we use the equation for our experiment

after rearranging terms

=( )

1 + c

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CHAPTER 4

RESULTS AND DISCUSSIONS

4.1 ZERO ORDER EQUATIONS

4.1.1 COD values of Bio carriers (30 min)

47 | P a g e


y = -63.079x + 1109.2R = 0.9372

0

200

400

600

800

1000

1200

0 5 10 15

Effl

uan

t co

nce

ntr

atio

n

time

zeroth order k(bio)

zeroth order k(bio)

Linear (zeroth orderk(bio))

Ceff= Ci 63.079t

Day inf cod eff cod

1 1180 1107

2 1210 1003

3 1166 900

4 1195 871

5 1239 841

6 1225 752

7 1187 642

8 1224 557

9 1127 399

10 1236 412

11 1190 363

12 1089 333

13 1248 377

14 1132 348

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day inf cod eff cod

1 1180 1077

2 1210 929

3 1166 856

4 1195 797

5 1239 767

6 1225 679

7 1187 593

8 1224 509

9 1127 375

10 1236 399

11 1190 339

12 1089 304


y = -64.368x + 1063.8R = 0.9538

0

200

400

600

800

1000

1200

0 5 10 15

Axi

s Ti

tle

Axis Title

zeroth order k 1 hour(bio)

zeroth order k 1hour(bio)

Linear (zeroth order k 1hour(bio))

Ceff= Ci 64.368t

49 | P a g e

day inf cod eff cod

1 1180 1047

2 1210 900

3 1166 826

4 1195 767

5 1239 738

6 1225 649.5

7 1187 569

8 1224 485

9 1127 351.5

10 1236 376

11 1190 327

12 1089 290.5

13 1248 334

4.1.4 BOD values of Bio carriers (30 min)

y = -62.813x + 1029R = 0.9499

0

200

400

600

800

1000

1200

0 5 10 15

Ellu

ant

con

cen

trat

ion

time

ZERO ORDER K 1.5 hour(bio)

ZERO ORDER K 1.5hour(bio)

Linear (ZERO ORDER K1.5 hour(bio))

Ceff= Ci 62.813t

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Day inf cod eff cod

1 708 642.96

2 750.2 606.856

3 687.94 510.3618

4 693.1 491.318

5 669.06 434.0682

6 686 400.54

7 688.46 351.7062

8 697.68 289.5828

9 619.85 194.656

10 667.44 189.108

11 618.8 151.632

12 588.06 121.014

13 698.88 141.232

14 656.56 136.184


y = -42.849x + 654.31R = 0.9541

0

100

200

300

400

500

600

700

0 5 10 15

Effl

uan

t co

nce

ntr

atio

n

time

zeroth order k(bio)

zeroth order k(bio)

Linear (zeroth orderk(bio))

Ceff= Ci 42.849t

51 | P a g e

day inf cod eff cod

1 708 624.96

2 750.2 553.474

3 687.94 491.2812

4 693.1 441.467

5 669.06 394.1082

6 686 352.8

7 688.46 302.6324

8 697.68 248.2692

9 619.85 169.059

10 667.44 148.716

11 618.8 120.588

12 588.06 117.1152

13 698.88 138.9696


y = -44.03x + 623.86R = 0.9557

0

100

200

300

400

500

600

700

0 5 10 15

Axi

s Ti

tle

Axis Title

zeroth order k 1 hour(bio)

zeroth order k 1hour(bio)

Linear (zeroth order k 1hour(bio))

Ceff= Ci 44.03t

52 | P a g e

day inf cod eff cod

1 708 614.04

2 750.2 542.996

3 687.94 466.7018

4 693.1 424.067

5 669.06 371.7576

6 686 336.28

7 688.46 302.4816

8 697.68 248.5428

9 619.85 156.134

10 667.44 142.9704

11 618.8 105.6848

12 588.06 98.064

13 698.88 117.152

4.1.6 COD values of Pumice stones (30 min)

y = -62.813x + 1029R = 0.9499

0

200

400

600

800

1000

1200

0 5 10 15

Ellu

ant

con

cen

trat

ion

time

ZERO ORDER K 1.5 hour(bio)

ZERO ORDER K 1.5hour(bio)

Linear (ZERO ORDER K1.5 hour(bio))

Ceff= Ci 62.813t

53 | P a g e

Day incod eff cod

1 1180 1136

2 1210 1092

3 1166 1018

4 1195 945

5 1239 870

6 1225 797

7 1187 666

8 1224 581

9 1127 496

10 1236 521

11 1190 479

12 1089 450

13 1248 493

14 1132 450

15 1089 435


y = -54.496x + 1131.2R = 0.9051

0

200

400

600

800

1000

1200

0 5 10 15 20

Effl

uan

t co

n

time

zeroth order k(plumice)


Linear (zeroth orderk(plumice))

Ceff= Ci 54.496t

54 | P a g e

day incod eff cod

1 1180 1107

2 1210 1047

3 1166 988

4 1195 915

5 1239 826

6 1225 753

7 1187 642

8 1224 545

9 1127 460

10 1236 484

11 1190 450

12 1089 406

13 1248 450

14 1132 421

15 1089 392


y = -54.768x + 1097.2R = 0.9084

0

200

400

600

800

1000

1200

0 5 10 15 20

Axi

s Ti

tle

Axis Title

zeroth order k 1 hour(plumice)

zeroth order k 1hour(plumice)

Linear (zeroth order k 1hour(plumice))

Ceff= Ci 54.768t

55 | P a g e

day incod eff cod

1 1180 1092

2 1210 1033

3 1166 959.5

4 1195 886

5 1239 797

6 1225 723

7 1187 618

8 1224 521

9 1127 436

10 1236 461

11 1190 424

12 1089 392

13 1248 435

14 1132 406

15 1089 377

4.1.9 BOD values of Pumice stones (30 min)

y = -54.252x + 1071.4R = 0.9005

0

200

400

600

800

1000

1200

0 5 10 15 20

Effl

uan

t co

nce

ntr

atio

n

time

ZERO ORDER K 1.5 hour(plumice)

ZERO ORDER K 1.5hour(plumice)

Linear (ZERO ORDER K1.5 hour(plumice))

Ceff= Ci 54.252t

56 | P a g e

Day incod eff cod

1 708 660.36

2 750.2 654.534

3 687.94 579.9818

4 693.1 527.307

5 669.06 456.4188

6 686 418.88

7 688.46 358.7416

8 697.68 296.286

9 619.85 235.609

10 667.44 241.2936

11 618.8 199.576

12 588.06 166.5522

13 698.88 185.2256

14 656.56 175.6472

15 653.4 176.058


y = -39.032x + 667.76R = 0.9254

0

100

200

300

400

500

600

700

0 5 10 15 20

Effl

uan

t co

n

time



Linear (zeroth orderk(plumice))

Ceff= Ci 39.032t

57 | P a g e

day incod eff cod

1 708 650.04

2 750.2 626.634

3 687.94 569.1612

4 693.1 502.976

5 669.06 412.587

6 686 401.1

7 688.46 351.7062

8 697.68 296.6964

9 619.85 228.206

10 667.44 214.6392

11 618.8 178.308

12 588.06 142.7922

13 698.88 168.1344

14 656.56 158.8272

15 653.4 156.792


y = -38.945x + 687.75R = 0.9284

0

100

200

300

400

500

600

700

0 5 10 15 20

Axi

s Ti

tle

Axis Title

zeroth order k 1 hour(plumice)

zeroth order k 1hour(plumice)

Linear (zeroth order k 1hour(plumice))

Ceff= Ci 38.945t

58 | P a g e

day incod eff cod

1 708 641.04

2 750.2 617.954

3 687.94 552.3462

4 693.1 493.087

5 669.06 403.6176

6 686 377.44

7 688.46 330.9016

8 697.68 262.086

9 619.85 215.006

10 667.44 215.568

11 618.8 164.788

12 588.06 141.1128

13 698.88 168.121

14 656.56 156.6928

15 653.4 154.326

4.1.12 COD values of Foam(30 min)

y = -54.252x + 1071.4R = 0.9005

0

200

400

600

800

1000

1200

0 5 10 15 20

Effl

uan

t co

nce

ntr

atio

n

time

ZERO ORDER K 1.5 hour(plumice)

ZERO ORDER K 1.5hour(plumice)

Linear (ZERO ORDER K1.5 hour(plumice))

Ceff= Ci 54.252t

59 | P a g e

Day incod eff cod

1 1180 1077

2 1210 856

3 1166 723

4 1195 605

5 1239 458

6 1225 369

7 1187 280

8 1224 272

9 1127 221

10 1236 280


y = -90.527x + 1012R = 0.885

0

200

400

600

800

1000

1200

0 5 10 15

Effl

uan

t co

nce

ntr

atio

n

time

zeroth order k(foam)


Linear (zeroth orderk(foam))

Ceff= Ci 90.527t

60 | P a g e

day incod eff cod

1 1180 1047

2 1210 826

3 1166 693

4 1195 576

5 1239 413

6 1225 310

7 1187 251

8 1224 261

9 1127 228

10 1236 251


y = -88.412x + 971.87R = 0.8654

0

200

400

600

800

1000

1200

0 5 10 15

Axi

s Ti

tle

Axis Title

zeroth order k 1 hour(foam)

zeroth order k 1hour(foam)

Linear (zeroth order k 1hour(foam))

Ceff= Ci 88.412t

61 | P a g e

day incod eff cod

1 1180 1033

2 1210 797

3 1166 664

4 1195 546

5 1239 369

6 1225 292

7 1187 238

8 1224 261

9 1127 221

10 1236 251

4.1.15 BOD values of Foam (30 min)

y = -85.37x + 936.73R = 0.8391

0

200

400

600

800

1000

1200

0 5 10 15

effl

uan

t co

nce

ntr

atio

n

time

ZERO ORDER K 1.5 hour(foam)

ZERO ORDER K 1.5hour(foam)

Linear (ZERO ORDER K1.5 hour(foam))

Ceff= Ci 85.37t

62 | P a g e

Day incod eff cod

1 708 617.88

2 750.2 530.72

3 687.94 392.173

4 693.1 350.9

5 669.06 260.7012

6 686 186.06

7 688.46 127.977

8 697.68 106.2024

9 619.85 96.756

10 667.44 104.4792


y = -59.586x + 605.11R = 0.9112

0

100

200

300

400

500

600

700

0 5 10 15

Effl

uan

t co

nce

ntr

atio

n

time



Linear (zeroth orderk(foam))

Ceff= Ci 59.586t

63 | P a g e

day incod eff cod

1 708 614.04

2 750.2 497.116

3 687.94 381.3524

4 693.1 320.218

5 669.06 216.3294

6 686 159.88

7 688.46 118.0416

8 697.68 99.9324

9 619.85 88.209

10 667.44 95.4936


y = -58.178x + 579.04R = 0.8887

-100

0

100

200

300

400

500

600

700

0 5 10 15

Axi

s Ti

tle

Axis Title

zeroth order k 1 hour(foam)

zeroth order k 1hour(foam)

Linear (zeroth order k 1hour(foam))

Ceff= Ci 58.178t

64 | P a g e

day incod eff cod

1 708 598.56

2 750.2 471.634

3 687.94 371.1218

4 693.1 288.956

5 669.06 179.1882

6 686 149.8

7 688.46 117.3862

8 697.68 92.9556

9 619.85 78.1605

10 667.44 88.8192

4.2 First order equations

y = -85.37x + 936.73R = 0.8391

0

200

400

600

800

1000

1200

0 5 10 15

effl

uan

t co

nce

ntr

atio

n

time

ZERO ORDER K 1.5 hour(foam)

ZERO ORDER K 1.5hour(foam)

Linear (ZERO ORDER K1.5 hour(foam))

Ceff= Ci 85.37t

65 | P a g e


Day inf cod eff cod -ln(s/so)bio

1 1180 1107 0.063861

2 1210 1003 0.187625

3 1166 900 0.25894

4 1195 871 0.316259

5 1239 841 0.387468

6 1225 752 0.48796

7 1187 642 0.614596

8 1224 557 0.787314

9 1127 399 1.038353

10 1236 412 1.098612

11 1190 363 1.187306

12 1089 333 1.184873

13 1248 377 1.197052

14 1132 348 1.179539

4.2.2COD values of Bio carriers (60 min)

y = 0.0998x - 0.0351R = 0.9497

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 5 10 15

-ln

(s/s

o)

time

first order k(bio)

first order k(bio)

Linear (first orderk(bio))

Ceff= Ci*e-0.0998t

66 | P a g e

day inf cod eff cod ln(s/so)bio

1 1180 1077 0.091335

2 1210 929 0.2642669

3 1166 856 0.309064

4 1195 797 0.4050468

5 1239 767 0.4795731

6 1225 679 0.590075

7 1187 593 0.69399

8 1224 509 0.8774314

9 1127 375 1.1003885

10 1236 399 1.1306742

11 1190 339 1.2557085

12 1089 304 1.2759874

13 1248 348 1.2770951


y = 0.1081x - 0.0063R = 0.9751

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 5 10 15

Axi

s Ti

tle

Axis Title

first order k 1 hour(bio_

first order k 1hour(bio_

Linear (first order k 1hour(bio_)

Ceff= Ci*e-0.1081t

67 | P a g e


1 1180 1047 0.119586

2 1210 900 0.295981

3 1166 826 0.34474

4 1195 767 0.443415

5 1239 738 0.518116

6 1225 649.5 0.634493

7 1187 569 0.735304

8 1224 485 0.925731

9 1127 351.5 1.165105

10 1236 376 1.190046

11 1190 327 1.291748

12 1089 290.5 1.321412

13 1248 334 1.318157


y = 0.1095x + 0.026R = 0.9722

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 5 10 15

-ln

(s/s

o)

time

first ORDER K 1.5 hour(bio)

first ORDER K 1.5hour(bio)

Linear (first ORDER K1.5 hour(bio))

Ceff= Ci*e-0.1095t

68 | P a g e

3 687.94 510.3618 0.298582

4 693.1 491.318 0.344083

5 669.06 434.0682 0.432672

6 686 400.54 0.538064

7 688.46 351.7062 0.671661

8 697.68 289.5828 0.879319

9 619.85 194.656 1.158244

10 667.44 189.108 1.261131

11 618.8 151.632 1.406326

12 588.06 121.014 1.580923

13 698.88 141.232 1.599075

14 656.56 136.184 1.573007


y = 0.1311x - 0.1223R = 0.9702

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 5 10 15

-ln

(s/s

o)

time

first order k(bio)

first order k(bio)

Linear (first orderk(bio))

Ceff= Ci*e-0.1311t

69 | P a g e


1 708 624.96 0.124756

2 750.2 553.474 0.304125

3 687.94 491.2812 0.336685

4 693.1 441.467 0.451071

5 669.06 394.1082 0.529248

6 686 352.8 0.664976

7 688.46 302.6324 0.821938

8 697.68 248.2692 1.033247

9 619.85 169.059 1.29923

10 667.44 148.716 1.501411

11 618.8 120.588 1.635402

12 588.06 117.1152 1.613671

13 698.88 138.9696 1.615224


y = 0.1415x - 0.0724R = 0.9659

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 5 10 15

Axi

s Ti

tle

Axis Title

first order k 1 hour(bio_

first order k 1hour(bio_

Linear (first order k 1hour(bio_)

Ceff= Ci*e-0.1415t

70 | P a g e


1 708 614.04 0.142384

2 750.2 542.996 0.323238

3 687.94 466.7018 0.388011

4 693.1 424.067 0.491283

5 669.06 371.7576 0.587632

6 686 336.28 0.712933

7 688.46 302.4816 0.822437

8 697.68 248.5428

project print

Documents

department civil engineering

master of engineering

e civil

g e acknowledgements

e project

g e contents title page

biological anaerobic

biological aerobic treatment