A REVIEW OF THE CENTRALIZED SEWERAGE SYSTEM FOR

KUCHING CITY

CHRISTINA UMPI

A thesis submitted

in fulfillment of the requirement for the degree of

Master of Engineering

Faculty of Engineering

UNIVERSITI MALAYSIA SARAWAK

2011

ii

ACKNOWLEDGEMENTS

With appreciation and heartfelt gratitude to my ex-supervisor Prof. Salim Said, who

guided, encouraged and advised me until his retiremet, to my supervisor Miss Nor Azalina Rosli

and co-supervisor Dr Onni Suhaiza Selaman for their kindness, guidance and encouragement.

I would like to thanks all my lecturer from the Department of Civil Engineering, Faculty

of Engineering for their encouragement and departing knowledge.

The State Planning Unit (SPU), Chief Ministers’ Department of Sarawak for granting me

the permission to conduct this research.

Sarawak Sewerage Service Department (SSD), Natural Resources and Environment

Board (NREB), Department of Environment (DoE) and Jurutera Jasa Consultant (Sarawak)

Sdn.Bhd for their generous supports.

My friends I say thank you for all the moments as student and hardship we have shared

together during our stay in UNIMAS.

And finally, my beloved parent and siblings for their love, care, support and

encouragement throughout my life.

v

TABLE OF CONTENTS

Page

ACKNOWLEDGEMENT ii

ABSTRACT iii

ABSTRAK iv

LIST OF FIGURES ix

LIST OF TABLES xi

LIST OF APPENDICES xii

LIST OF ABBREVIATIONS xiii

CHAPTER 1 INTRODUCTION

1.1 General Background 1

1.2 Study Background 2

1.3 Objective 6

CHAPTER 2 LITERATURE REVIEW

2.1 Introduction 7

2.2 Wastewater Characteristics 8

2.2.1 Physical Characteristics 8

2.2.2 Chemical Characteristics 9

2.2.3 Biological Characteristics 10

vi

2.3 Population Equivalent (PE) 13

2.4 Sewage Collection 14

2.5 Wastewater Treatment Plant 15

2.6 Primary Treatment 16

2.7 Secondary (Biological) Treatment 17

2.7.1 Activated Sludge Treatment 18

2.7.2 Trickling Filter 20

2.7.3 Pond Treatment Processes 21

2.8 Tertiary Treatment 23

2.9 Sewage Disposal 24

2.10 Types of Sewage system 25

2.10.1 Centralized Sewerage System 26

2.10.2 Decentralized Sewerage System 26

2.11 Non Point Source Pollution (NPS) 27

2.11.1 Nonpoint Source Pollutants 28

2.11.2 Source of NPS Pollutants 30

2.12 Water Quality Parameters 31

2.12.1 Physical Parameter 31

2.12.2 Chemical Parameters 32

2.12.3 Biological Parameters 35

2.13 Water Quality Index 36

2.14 Existing Sewerage System in Kuching City 39

vii

2.15 Proposed Centralized Sewerage System in Kuching City 49

CHAPTER 3 METHODOLOGY

3.1 Introduction 55

3.2 Research Methods and Data Collection 58

3.2.1 Sampling Plan 59

3.2.2 Samples Container, Samples Volume and Preservation 62

3.2.3 Sample Analysis 63

3.2.4 Data Analysis 64

CHAPTER 4 RESULTS AND DISCUSSION

4.1 Introduction 65

4.2 Comparison between Existing System and Proposed System

4.2 Comparison between Influent and Effluent 66

4.4 Sampling Results and Water Quality Parameter Analysis 70

4.4.1 pH 71

4.4.2 Turbidity 72

4.4.3 Dissolved Oxygen (DO) 73

4.4.4 Biochemical Oxygen Demand (BOD) 74

4.4.5 Chemical Oxygen Demand (COD) 75

4.4.6 Total Suspended Solids (TSS) 76

4.4.7 Ammoniacal Nitrogen (NH3-N) 77

viii

4.4.8 Total Coliform Count (TCC) and Feacal Coliform Count (FCC) 78

4.4.9 Water Quality Index (WQI) 80

CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS

5.1 General 82

5.2 Conclusion 82

5.3 Recommendation for Future Study 84

REFERENCES 85

APPENDICES 91

xiii

LIST OF ABBREVIATIONS

AN Ammoniacal nitrogen

APHA American Public Health Association

BOD Biochemical Oxygen Demand

COD Chemical Oxygen Demand

DANCED Danish Cooperation for Environment and Development

DBKU Dewan Bandaraya Kuching Utara (Kuching North City Hall)

DID Department of Irrigation and Drainage

DO Dissolved Oxygen

DoE Department of Environment

FCC Feacal Coliform Count

INWQS Interim National Water Quality Standards

MBKS Kuching City South Council

NREB Natural Resource and Environment Board

Ntot Total Nitrogen

NTU Nephelometric Turbidity Unit

PE Population Equivalent

TSS Total Suspended Solid

SSD Sarawak Sewerage Service Department

SUB Sustainable Urban Development

TCC Total Coliform Count

xiv

WQI Water Quality Index

WWTP Wastewater Treatment Plant

ix

LIST OF FIGURES

Page

Figure 1.1 Location of Kuching City 3

Figure 1.2 Study Area of Centralized Sewerage System for Kuching City 5

Figure 2.1 Typical Stages in the Conventional Treatment of Sewage 16

Figure 2.2 Conventional Activated Sludge Plant 19

Figure 2.3 Trickling Filter 20

Figure 2.4 Schematic Diagram of Facultative Pond Relationship 22

Figure 2.5 Centralized Sewerage System 26

Figure 2.6 Decentralized Sewerage System 27

Figure 2.7 Black Water and Grey Water Outlet to Storm Water Drain in Kuching 40

Figure 2.8 Filtering Equipment Installed at Washing Sinks 41

Figure 2.9 Conventional Septic Tank 42

Figure 2.10 Estimated Discharges to Sungai Sarawak of BOD, Nitrogen and 45

Phosphorous in Black Water in Case none of the septic Tanks

are Not Functioning and in the Case of All Septic tanks are

Functioning Optimally

Figure 2.11 Treatment Plant Overall Process Flow Diagram 50

Figure 2.12 Conventional Activated Sludge Process Flow Diagram 52

Figure 2.13 Sarawak River DO level without any centralized system (red line), 54

x

completion of package 1 of KCWMS (blue line), and completion of

package 1, 2, 3 and 4 of KCWMS (green line)

Figure 3.1 Coverage Area of Centralized Sewerage System for Kuching City 56

Figure 3.2 Tributaries of Sungai Sarawak in the Kuching City 57

Figure 3.3 Research Methodology Flow Chart 58

Figure 3.4 Surface Water Sampling Locations 60

Figure 4.1 Comparison Between Influent (without any centralized system) and 69

Expected Effluent (with centralized system)

Figure 4.2 pH Values for All Sampling Point 71

Figure 4.3 Turbidity Values for All Sampling Point 72

Figure 4.4 Dissolved Oxygen Values for All Sampling Point 73

Figure 4.5 Biochemical Oxygen Demand Values for All Sampling Point 74

Figure 4.6 Chemical Oxygen Demand Values for All Sampling Point 75

Figure 4.7 Total Suspended Solids Values for All Sampling Point 76

Figure 4.8 Ammonia Nitrogen, NH3-N Values for All Sampling Point 77

Figure 4.9 Total Coliform Count Values for All Sampling Point 79

Figure 4.10 Feacal Coliform Count Values for All Sampling Point 79

Figure 4.11 Map of Water Quality Identification of Sungai Sarawak and Tributaries 81

Based on the NWQSM

xi

xi

LIST OF TABLES

Page

Table 2.1 Physical Characteristics of Wastewater 9

Table 2.2 Typical Chemical Characteristics of Domestic Wastewater 10

Table 2.3 Recommended Population Equivalents 13

Table 2.4 Classes in Malaysian Water Quality Index 39

Table 2.5 Pollutants in Grey water From Households 46

Table 2.6 Pollutants in Wastewater from Food Outlets in Kuching 47

Table 2.7 Estimated Loads of Pollutant to Sungai Sarawak and Tributaries from 48

Different Types of Sources in Kuching.

Table 2.8 Raw Wastewater Composition 49

Table 2.9 Expected Treated Effluent Qualities for Proposed System 53

Table 3.1 Details of Surface Water Sampling Locations 61

Table 3.2 Sampling Technique and preservation method 62

Table 3.3 Method and Apparatus Used for Analysis Water Sample 63

Table 4.1 Summary Results of In-situ Test and Laboratory Analysis of Water 70

Samples

Table 4.2 Classification of Rivers Based on Water Quality Index (WQI) 80

xii

LIST OF APPENDICES

Page

Appendix 1 State Inventory of Wastewater Treatment Facility as At 91

31 December 2009

Appendix 2 Environmental Quality Act, 1974 Parameter Limits Of Effluent of 92

Standards A and B

Appendix 3a Laboratory Procedure for Biochemical Oxygen Demand (BOD) 93

Appendix 3b Laboratory Procedure for Total Suspended Solids (TSS) 97

Appendix 4a National Water Quality Standards for Malaysia 100

Appendix 4b Malaysian Interim Water Quality Standard Classification 101

Appendix 5 In-situ Test for Sungai Sarawak 102

Appendix 6 Full Laboratory Analysis Results 103

Appendix 7 Water Quality Index and Sub-Index 104

iii

ABSTRACT

The centralized sewerage system for Kuching City currently under construction and this

project is expected to be completed by October 2012. This system shall collect all the wastewater

through sewer network to a centralized treatment plant and using the activated sludge system to

treat the wastewater. The effluent after being discharged into a constructed wetland before finally

flowing into Sarawak River is believed to comply with Standard A of the Environmental Quality

Act requirement. Prior to this, Sarawak River and its tributaries within the study area are

polluted. The main source of the pollution is raw and insufficiently treated sewage and

wastewater, which is eventually drained to Sarawak River. The water quality of different point of

the entire river system has been classified according to the Malaysian Interim National Water

Quality Standards (NWQSM). The water quality in confluent of Sungai Bintangor, Sungai

Sarawak, Holiday Inn, confluent of Sungai Padungan, confluent of Sungai Sekama, Sungai

Sarawak, Bintawa Causeway and Bako Causeway is polluted and falls between the class III and

class IV of the NWQSM. Very high concentrations of BOD and COD are observed in samples

tested. The content of bacteria is extremely high and the water poses a health risk. The water

quality in Sungai Sarawak, Satok Bridge, Upstream and Downstream Barrage are slightly

polluted and falls between the class II and class III of the NWQSM.

iv

ABSTRAK

Sistem pembetungan berpusat bagi Bandaraya Kuching sedang dalam pembinaan dan

projek ini dijangka siap menjelang bulan Oktober 2012. Sistem ini akan mengumpul semua air

kumbahan melalui rangkaian pembetung ke loji rawatan berpusat dan menggunakan sistem

enapcemar teraktif untuk merawat air kumbahan. Efluen akan dilepaskan ke kawasan tanah

basah dan kemudian dialirkan Sungai Sarawak dan dipercayai akan mematuhi Piawaian A

keperluan Akta Kualiti Alam. Sungai Sarawak dan juga anak sungai dalam linkungan kajian ini

menunjukkan bahawa sungai tersebut tercemar. Punca utama pencemaran tersebut adalah dari

air kumbahan tidak terawat yang disalurkan terus ke Sungai Sarawak. Kualiti air dari tempat

persampelan yang berbeza di sepanjang sungai telah dikelaskan mengikut “Malaysian Interim

National Water Quality Standards (NWQSM)”. Kualiti air di kuala Sungai Bintangor, Sungai

Sarawak, Holiday Inn, kuala Sungai Padungan, kuala Sungai Sekama, Sungai Sarawak, tambak

Bintawa dan tambak Bako adalah tercemar dan dikatagorikan antara kelas III dan kelas IV

NWQSM. Dari keputusan kajian persampelan menunjukkan nilai “BOD” dan “COD” adalah

sangat tinggi begitu juga kandungan bacteria yang menyebabkan pencemaran di dalam sungai

tersebut. Kualiti air di Sungai Sarawak, Jabatan satok, di hulu dan di hilir “Barrage” juga agak

tercemar dan dikatagorikan antara kelas II dan Kelas III NWQSM.

1

CHAPTER 1

INTRODUCTION

1.1 General Background

As early as 100AD, mankind had started to realize the important of sanitation system.

During the Roman’s era, they built splendid public toilets and bath area that linked to

sophisticated water and waste delivery systems that still have the same similarity to the

present ones. The system involved flushing and flowed into central channel of rock pipes that

today we call it sewer line but of course with different material. Such material today is of

verified Clay Pipe, Ductile Iron Pipe and high Density Polyethylene or all. This sewer water

was then discharged to the nearest river or stream.

For the last 30 years, Malaysia wastewater treatment technologies used overhang

latrines, pit privy, bucket system and pour flush system until the introduction of a more

modern septic tank and Imhoff tank system. Only the last two decades, we saw the emergence

of the new technologies in the form of oxidation ponds, aerated lagoons, package systems and

a variety of mechanical plants. Even though with the growing changes in the wastewater

treatment, sewage still remains as a current major pollutant of our inland waterway.

2

Over the years, water pollution has come out as major issues. The main pollutants

include pathogen, organic matter, nutrients, heavy metals and toxic chemicals, sediment and

suspended solids, silt and salt. In developing countries, the rivers in the urban areas are

heavily polluted with domestic sewage, industrial effluents, chemical and solid wastes

(UNEP, 2002).

In Kuching, housing estates still use septic tank as the most common domestic

wastewater treatment system. From the survey outcome conducted by Drainage and Irrigation

Department of Sarawak, it had recorded that there were about 74,000 septic tanks in Kuching

(refer to Appendix 1). For area where larger population are involve, Imhoff tank system were

usually used in single building while oxidation pond for hospital, airport, hotel and some

institutions. Besides this two, there were a few local centres where their wastewater treatment

using activated sludge system. The storm water drains and river acted as combined sewer

receptors for all types of wastewater such as septic tank effluent, grey water from residential

activities as well as liquid waste from industries.

1.2 Study Background

Kuching City is the capital of the State of Sarawak located on the island of Borneo and

the city is located on the banks of the Sarawak River (refer to Figure 1.1). The population

estimated more than half a million covering an area of approximately 431 square of

kilometers, reaching out right to the South China Sea in the north.

3

Sungai Sarawak is the lifeblood of Kuching city. This river serves as a life-sustaining

water source for the residents in Kuching City and the entire ecosystem surrounding in the

areas. Besides, this river is also an important navigation channel that connected a few

landmarks in Kuching City for river taxi. Water related sport activities are held in the river

such as Sarawak Regatta and city celebration activity like decorated river float to boast

Sarawak tourism industry.

Figure 1.1: Location of Kuching City

Source: Google Map

4

With rapid growth and urbanization, Kuching City is currently experiencing “growing

pains” particularly in the areas of socio-economic and Municipal infrastructural demands

bring this wastewater issue into a big subject of concern for the Government not to ignore.

Increasing pollution discharges from the existing sewer systems into the rivers are beginning

to worsen the water quality and threaten the well being of the streams and rivers, where this

pollution has developed smell and killing the ecosystems in and around it.

As a responsible government, a Centralized Sewerage System to collect all the

wastewater in Kuching city is introduced. This system shall collect all the wastewater through

a network of underground pipes to a centralized treatment plant. From the plant, a process to

treat the wastewater using the activated sludge system is believed to have treated effluents

from the plant comply with Standard A of the Environmental Quality Act requirement (refer

to Appendix 2). The effluent shall be discharged into a constructed wetland before finally

flowing into Sarawak River.

The centralized sewerage system is currently under construction to reduce pollution

level of the city’s waterways due to insufficient treatment in septic / Inhoff tanks. The

coverage study area of centralized sewerage system for Kuching City (Package 1) is as shown

in Figure 1.2 which covers the commercial and densely-populated areas of the central

business district. This project is expected to be completed by October 2012. For this project,

three main components are involved. They are Wastewater Treatment Plant, Sewer Network

5

and Property Connections. It costs 530 million covering public sewer line of 64.1 km and a

treatment plant design for 100,000PE expandable to 400,000PE.

A “Design and Construction” contract is awarded to a turnkey contractor Kumpulan

Nishimatsu - Hock Seng Lee Consortium on 30th September 2008. The local consultant is

Jurutera Jasa (Sarawak) Sdn Bhd in association with CH2M Hill USA. Sarawak Sewage

Department is the government representative responsibled to manage and oversee the project.

On project completion this organization shall also be the authority that responsible to manage

and control the system for the Sarawak Government.

Figure 1.2: Study Area of Centralized Sewerage System for Kuching City (Package 1).

Source: Sewerage Service Department Sarawak.

6

1.3 Objectives

The objectives of this study are:

i. To study of the existing system and the proposed centralized sewerage system

for Kuching City.

ii. To compare and analyze the existing influent and expected effluent for the

proposed system.

iii. To evaluate the affected river water quality within the study area.

Furthermore, it provides the exposure on the application and performance of the

theoretical knowledge thus enhance us the opportunity to develop new idea and approach in

addressing the appropriateness of setting up a centralized sewerage system in Kuching city.

7

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

Sewerage refers to the collection, treatment and disposal of liquid wastes (McGhee,

1991). A sewage collection system consists of pipes network, pumping stations, channels, and

appurtenances that convey wastewater to treatment plant, storage, or disposal. The wastewater

may include domestic sewage, industrial sewage, storm sewage, or a mixture of the three.

Domestic sewage carries human wastes called black water (wastewater from toilet)

and grey water from homes, public building, or commercial and industrial establishment.

Industrial sewage is the wastewater from manufacturing processes, usually carrying a variety

of chemical compounds. Storm sewage is the surface runoff caused by rainfall which carries

organics, suspended and dissolved solids, and other substances picked up as it travels over the

ground.

8

2.2 Wastewater Characteristics

Wastewater is characterized in terms of its physical, chemical, and biological

compositions (Tchobangolous and Burton, 1991). Many of the parameter in physical,

chemical and biological are interrelated. For example, temperature, a physical property,

affects both the biological activity in the wastewater and the amounts of gases dissolved in the

wastewater.

2.2.1 Physical Characteristics

The most important physical characteristic of wastewater is its total solids content,

which is composed of floating matter, settles able matter, colloidal matter, and matter in

solution (Tchobangolous and Burton, 1991). Other important physical characteristics include

temperature, color odor, and turbidity. The principal physical properties of water are

summarized in Table 2.1.

9

Table 2.1: Physical Characteristics of Wastewater

Characteristic

Description

Temperature

Color

Odors

Turbidity

The temperature of wastewater is slightly higher than that of water supply.

Temperature has effect upon microbial activity, solubility of gas, and

viscosity. The temperature of wastewater varies slightly with the seasons,

but is normally higher than air temperature during most of the year and

lower only during the hot summer months.

Fresh wastewater is light gray. Stale or septic wastewater is dark gray or

black.

Fresh wastewater may have a soapy or oily odor, which is somewhat

disagreeable. Stale water has putrid odors due to hydrogen sulphide, and

other products of decomposition. Industrial wastes impart other typical

odors. Because of odors associated with wastewater treatment facilities, area

residents have often vigorously resisted and rejected wastewater treatment

plant projects.

Turbidity in wastewater is caused by a wide variety of suspended solids. In

general, stronger wastewaters have higher turbidity.

Source: Qasim, 1994