Cover

Title Page

Copyright Page

Contents

Section 1: Water basics

1.1 Introduction

1.2 The hydrological cycle

1.3 The natural aquatic environment

1.3.1 Water, the medium of life

1.3.2 Dissolved oxygen – measurement

1.3.3 Dissolved oxygen – rate

1.3.4 Dissolved oxygen – variation

1.3.5 Physical characteristics of natural water

1.3.6 Chemical characteristics of natural water

1.3.7 Biological characteristics of natural water –species

1.3.8 Biological characteristics of natural water – biological indicators

1.4 Further SAQs

1.5 Summary

Section 2: Pollution of the aquatic environment

2.1 Introduction

2.2 Sources of pollution

2.2.1 Discharges from sewage works

2.2.2 Discharges from manufacturing and industrial plants

2.2.3 Discharges from animal rearing, fish farming and agriculture

2.2.4 Seepage from domestic and industrial landfill sites

2.2.5 Urban surface water run-off

2.3 Summary

Section 3: The effects of pollutants on the aquatic environment

3.1 Introduction

3.2 Organic materials

3.3 Plant nutrients

3.4 Toxic pollutants

3.4.1 Pesticides

3.4.2 Acidity and heavy metals

3.5 Physical pollutants

3.5.1 Suspended solids

3.5.2 Immiscible liquids

3.5.3 Discharges contributing to a temperature change

3.5.4 Discharges causing variations in flow rate

3.5.5 Substances causing taste, odour and coloration

3.6 Biological pollutants

3.6.1 Pathogenic bacteria

3.6.2 Coliforms

3.6.3 Faecal streptococci

3.6.4 Clostridium perfringens

3.6.5 Viruses

3.6.6 Protozoa

3.6.7 Helminths

3.6.8 Other biological pollutants

3.6.9 Typical pathogens

3.7 Further SAQs

3.8 Summary

Section 4: Sewage treatment

4.1 Introduction

4.2 Transporting sewage

4.2.1 Drains

4.2.2 Sewers

4.2.3 Dry weather flow

4.2.4 Gravity flow

4.3 Overview of sewage treatment

4.3.1 Storm water tanks

4.3.2 Design of sewage treatment processes

4.4 Preliminary treatment

4.5 Primary treatment

4.6 Secondary treatment

4.6.1 Biological filters – overview

4.6.2 Biological filters – process

4.6.3 Biological filters – practical applications

4.6.4 Activated sludge – overview

4.6.5 Activated sludge – aeration systems

4.6.6 Activated sludge – BOD removal

4.6.7 Activated sludge – secondary sedimentation

4.6.8 Elimination of pathogens

4.6.9 Comparison of systems

4.6.10 Control and monitoring

4.7 Secondary treatment of industrial effluents

4.7.1 Overview of industrial effluents

4.7.2 Treatability of effluents

4.7.3 Bioaugmentation

4.8 Variants of the biological treatment system

4.8.1 Oxidation ditch

4.8.2 Pure oxygen activated sludge process

4.8.3 Deep Shaft™ process

4.8.4 Rotating biological contactor

4.8.5 Hybrid activated sludge system

4.8.6 Membrane bioreactor

4.8.7 Waste stabilisation ponds

4.8.8 Septic tank

4.8.9 Use of plants in wastewater treatment

4.8.10 Package treatment plants

4.8.11 Chemical treatment of sewage

4.8.12 Waterless sewage treatment

4.8.13 Relative costs

4.9 Tertiary treatment

4.9.1 Suspended solids removal

4.9.2 Nutrient removal – ammonia and nitrates

4.9.3 Nutrient removal – phosphorus

4.9.4 Nutrient removal – combined nitrogen and phosphorus

4.9.5 Non-biological methods of removing nitrogen and phosphorus

4.10 Advanced wastewater treatment

4.11 Decentralised wastewater treatment systems

4.12 Sustainable urban drainage systems

4.13 Further SAQs

4.14 Summary

Section 5: Sludge treatment and disposal

5.1 Introduction

5.2 Sludge production and sludge characteristics

5.3 Methods of treatment

5.3.1 Preliminary conditioning

5.3.2 Anaerobic digestion

5.3.3 Dewatering

5.3.4 Composting

5.4 Methods of reuse or disposal

5.5 Further SAQs

5.6 Summary

Section 6: Water quality tests

6.1 Introduction

6.2 Oxygen demand

6.2.1 Plotting dissolved oxygen concentration

6.2.2 The BOD test

6.2.3 BOD rate constant

6.2.4 Use of BOD test

6.2.5 The COD test

6.2.6 Total organic carbon

6.3 Estimation of physical, chemical and microbiological components

6.3.1 Temperature

6.3.2 pH

6.3.3 Solids

6.3.4 Hardness

6.3.5 Alkalinity

6.3.6 Nitrogen compounds

6.3.7 Phosphates

6.3.18 Chlorides

6.3.9 Metals

6.3.10 Oil

6.3.11 Toxic chemicals

6.3.12 Radiation

6.3.13 Odour, colour and turbidity

6.3.14 Coliforms

6.3.15 Other microorganisms

6.4 Toxicity testing

6.5 Further SAQs

6.6 Summary

Section 7: Industrial wastewater treatment

7.1 Introduction

7.2 Trade effluent control

7.3 Summary

Section 8: River quality modelling

8.1 Introduction

8.2 Dispersion of pollutants in water

8.3 Biochemical oxygen demand

8.3.1 Use of equations

8.3.2 Oxygen demand due to nitrification

8.4 Dissolved oxygen

8.4.1 Initial dissolved oxygen deficit

8.4.2 Reaeration coefficient

8.4.3 Critical distance and critical deficit

8.4.4 Effect of nitrification

8.5 Nutrients and eutrophication potential

8.5.1 Estimating in-stream nutrient concentrations

8.6 Total coliform bacteria

8.7 Summary

Glossary

References

Acknowledgements

Answer

Description