Alfred Fosu Thesis _MSc Envt Sci.

124 Pages·2010·1.47 MB·English

by  Alfred Fosu

KWAME NKRUMAH UNIVERSITY OF SCIENCE AND
TECHNOLOGY

COLLEGE OF SCIENCE

FACULTY OF BIOSCINCES

DEPARTMENT OF THEORETICAL AND APPLIED BIOLOGY

ASSESSING THE EFFICIENCY OF THE KNUST SEWAGE
TREATMENT PLANT

BY

ALFRED FOSU

JUNE 2009

ASSESSING THE EFFICIENCY OF KNUST SEWAGE
i
TREATMENT PLANT

by

Alfred Fosu BSc (Hons) Nat. Res. Mgt.

A Thesis submitted to the Department of Theoretical and Applied
Biology,
Kwame Nkrumah University Of Science And Technology
In partial fulfilment of the requirements for the degree
of

MSc ENVIRONMENTAL SCIENCE
Faculty Of Biosciences
College Of Science

June 2009

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DECLARATION
I hereby declare that this submission is my own work towards the MSc and that, to the
best of my knowledge, it contains no material previously published by another person
nor material which has been accepted for the award of any other degree of the
University, except where due acknowledgement has been made in the text.

ALFRED FOSU ... ................ .......................
(Student) Signature Date

Certified by:

................................ ............................. ..............................
DR. BENARD FEI-BAFFOE Signature Date
(Supervisor)
Certified by:

............................ .......................... ..............................
DR. P. K. BAIDOO Signature Date
(Head of Dept.)

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TABLE OF CONTENTS
COVER PAGE…………………………………………………………………………...i
TITLE PAGE…………………………………………………………………………....ii
DECLARATION.............................................................................................................iii
ABSTRACT....................................................................................................................vii
LIST OF TABLES...........................................................................................................ix
LIST OF FIGURES...........................................................................................................x
LIST OF PLATES............................................................................................................xi
LIST OF ABBREVIATIONS.........................................................................................xii
ACKNOWLEDGEMENTS...........................................................................................xiii
DEDICATION...............................................................................................................xiv
CHAPTER ONE ................................................................................................................... 1
1.0 INTRODUCTION .......................................................................................................... 1
1.1 Background ............................................................................................................. 1
1.2 Problem Statement .................................................................................................. 3
1.3 Justification ............................................................................................................. 3
1.4 Objectives ............................................................................................................... 4
CHAPTER TWO .................................................................................................................. 5
2.0 LITERATURE REVIEW ............................................................................................... 5
2.1 Historical Background to Wastewater Treatment .................................................. 5
2.2 Domestic Wastewater Treatment in Ghana ............................................................ 7
2.2.1 Treatment and Disposal of domestic wastewater in Kumasi ........................... 7
2.4 The Wastewater Treatment Plant ......................................................................... 10
2.6 Some Parameters used to Determine Effluent Quality and their Removal
Mechanisms in Sewage Treatment Plants .................................................................. 22
2.6.1 pH .................................................................................................................. 22
2.6.2 Temperature ................................................................................................... 23
2.6.3 Pathogens ....................................................................................................... 23
2.6.4 Biochemical Oxygen Demand ....................................................................... 28
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2.6.5 Total Suspended Solids ................................................................................. 31
2.6.6 Nitrogen and its Derivatives .......................................................................... 33
2.6.7 Phosphorus .................................................................................................... 36
CHAPTER THREE ............................................................................................................ 38
3.0 METHODOLOGY ....................................................................................................... 38
3.1 The Study Area ..................................................................................................... 38
3.1.1 Climate .......................................................................................................... 38
3.1.3 Environmental Situation ................................................................................ 38
3.1.4 The KNUST Campus .................................................................................... 39
3.2 Methods Used for Data Collection ....................................................................... 40
3.2.1 Sampling Location and Frequency ................................................................ 40
3.3 Procedures for Laboratory Analysis ..................................................................... 47
3.3.1 Biochemical Oxygen Demand (BOD ) ......................................................... 47
5
3.3.2 Total Suspended Solids ................................................................................. 49
3.3.3 Turbidity ........................................................................................................ 50
3.3.4 pH .................................................................................................................. 50
3.3.5 Escherichia coli, Salmonella and Coliforms ................................................. 51
3.3.5 Nutrients ........................................................................................................ 52
3.5 Data Analysis ........................................................................................................ 52
CHAPTER FOUR .............................................................................................................. 53
4.0 RESULTS ..................................................................................................................... 53
4.1 Physico- Chemical Parameters ............................................................................. 53
4.1.1 Temperature ................................................................................................... 54
4.1.2 Hydrogen Ion Concentration (pH) ................................................................. 55
4.1.3 Turbidity ........................................................................................................ 56
4.1.4 Total Suspended Solids (TSS) ....................................................................... 58
4.1.5 Phosphate ....................................................................................................... 59
4.1.6 Nitrate ............................................................................................................ 60
4.2.1 Escherichia coli ............................................................................................. 62
4.2.2 Salmonella ..................................................................................................... 63
4.2.3 Total Coliforms ............................................................................................. 64
4.4 Impact of Effluent on Water Quality of Wiwi River ............................................ 67
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4.5 Administrative Factors contributing to the Performance of the Treatment Plant......... 68
CHAPTER FIVE ................................................................................................................ 70
5.0 DISCUSSION ............................................................................................................... 70
5.1. Physico-Chemical Properties ............................................................................... 70
5.1.1 Temperature ................................................................................................... 70
5.1.2 Hydrogen Ion Concentration (pH) ................................................................. 71
5.1.4 Total Suspended Solids removal ................................................................... 72
5.1.5 Nutrients removal .......................................................................................... 73
5.1.6 Biochemical Oxygen Demand removal ......................................................... 75
5.2 Impact of effluent on Wiwi River ........................................................................ 78
CHAPTER SIX .................................................................................................................. 80
6.0 CONCLUSION AND RECOMMENDATIONS ................................................ 80
6.1 Conclusion ....................................................................................................... 80
6.2 Recommendations ................................................................................................ 81
REFERENCES ................................................................................................................... 82

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ABSTRACT
It is well known that successive stages of treatment at a sewage plant reduce the
quantity of suspended solids, the organic matter content, the nutrient constituent, the
microbial load and the bio- chemical oxygen demand of sewage, so that the polluting
strength of the final effluent becomes a small fraction of that of the sewage received at
the plant. A performance efficiency investigation was therefore conducted on the
KNUST sewage treatment plant which treats sewage via percolating filters and humus
tanks. Samples taken at various stages of treatment over a period of four months were
subjected to microbiological and physico chemical examination to find the reductions in
levels of pollutants as the sewage goes through the treatment system. The studied
parameters included Temperature, Hydrogen ion concentration, Turbidity, Nitrate,
Phosphate, Biochemical oxygen demand, Total suspended solids, Escherichia coli,
Salmonella and Total coliform to assess the performance efficiency of the plant in
reducing their polluting strength. Plate count on nutrient agar of E. coli, Salmonella and
Coliforms were performed. Laboratory Chemical analyses were done for the physic-
chemical parameters including temperature, pH, Turbidity, TSS and BOD Nitrate and
5,
Phosphate. The data as a whole gave a general picture of the extent to which treatment
at the works reduced the parameters at the various treatment units of the plant. The data
were analyzed using Microsoft excel and Statistical Package for Social Scientist (SPSS)
software packages. One way analysis of variance (ANOVA) was ran to determine
significant differences of the parameters per treatment unit of the plant.
After analyzing the data, it was evident that plant’s performance efficiency is below the
EPA Ghana standard as most of the parameters were not treated to meet standard for
discharge. The effluent discharged into the Wiwi River has pollutant levels of TSS,
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BOD5, Total Coliform, E. coli Phosphate and Nitrate being higher than the EPA
permissible levels for discharge. Turbidity was reduced by 82%, TSS by 86%, BOD by
5
68.9%, Phosphate by 72.8%, Nitrate by 70.5% E. coli by 91%, Salmonella by 77% and
Total coliform by 91.1%.
Upon critical assessment of the performance of the KNUST Sewage Treatment Plant, it
was found that operational design and administrative factors combined to cause the poor
performance of the plant.
The plant lacked process monitoring and testing on which to base control decisions.
Excessive hydraulic loading (too much wastewater for the capacity of the STP)
impaired the performance of the plant. It is highly recommended that regular
maintenance of the plant should be ensured and also competent and well resourced crew
should be recruited to manage the plant.

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LIST OF TABLES

Table 2.1: Effluent quality of Asafo sewage treatment plant............................................8
Table 2.2: Composition of Domestic Wastewater...........................................................10
Table 4.1: Mean values of physico-chemical parameters of the sampling points...........53
Table 4.2 Comparison of Parameters Considered Under Study To Ghana
EPA Effluent Discharge Standard...................................................................66
Table 4.3: Impact of the various Parameters on the water quality of the Wiwi River....67

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LIST OF FIGURES

Figure 3.1 Layout of KNUST Sewage Treatment plant..................................................41
Figure 4.1 Mean of Temperature.....................................................................................55
Figure 4.2 Mean of pH....................................................................................................56
Figure 4.3 Mean of Turbidity..........................................................................................57
Figure 4.4 Mean of TSS..................................................................................................58
Figure 4.5 Mean of Phosphate.........................................................................................59
Figure 4.6 Mean of Nitrate..............................................................................................60
Figure 4.7 Mean of BOD.................................................................................................61
Figure 4.8 Microbial quality of the sewage at various treatment points.........................62
Figure 4.9 Level of E-coli reduction per treatment unit of the plant...............................63
Figure 4.10 Salmonella removal within the various treatment units...............................65

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