Solid Wastes Management

Solid wastes management

Edited by Stephen Burnley

Published by:

John Wiley & Sons Ltd

The Atrium

Southern Gate

Chichester

West Sussex

PO19 8SQ

in association with:

The Open University

Walton Hall

Milton Keynes

MK7 6AA

First published 2014.

Copyright © 2014 The Open University

Cover image © Artur Marciniec/Alamy

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, transmitted or utilised in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without written permission from the publisher or a licence from the Copyright Licensing Agency Ltd. Details of such licences (for reprographic reproduction) may be obtained from the Copyright Licensing Agency Ltd, Saffron House, 6–10 Kirby Street, London EC1N 8TS (website www.cla.co.uk).

Edited and designed by The Open University.

This publication forms part of the Open University module T868 Environmental monitoring and protection. Details of this and other Open University modules can be obtained from the Student Registration and Enquiry Service, The Open University, PO Box 197, Milton Keynes MK7 6BJ, United Kingdom (tel. +44 (0)845 300 60 90; email [email protected]).

www.open.ac.uk

British Library Cataloguing Publication Data:

A catalogue record for this book is available from the British Library.

Library of Congress Cataloging-in-Publication Data:

A catalog record for this book has been requested.

ISBN 978 1 1188 6393 0

1.1

Contents

Section 1: Wastes basics

1.1  Introduction

1.2  What is waste?

1.3  Waste categories

1.4  Waste quantities and composition

1.5  Household wastes

1.6  Waste policy and regulation

1.7  Waste reduction and reuse

1.8  Summary

Section 2: Waste management technologies

2.1  Introduction

2.2  Landfill

2.3  Waste incineration

2.4  Advanced thermal processing techniques

2.5  Anaerobic digestion

2.6  Composting

2.7  Materials recycling

2.8  Mechanical–biological treatment

2.9  Summary

Section 3: Waste management process and environmental impact modelling

3.1  Introduction

3.2  Leachate formation within a landfill

3.3  Other landfill processes

3.4  Incineration emissions

3.5  Life-cycle assessment

3.6  Summary

Section 4: Health impacts of waste management

4.1  Introduction

4.2  Emissions and impacts

4.3  Critical reading of the literature

4.4  Assessing the health impacts of waste management

4.5  Health and safety issues associated with waste collection

4.6  Health impacts of landfill

4.7  Health impacts of incineration

4.8  Health impacts of recycling and biological processing

4.9  Summary

Section 5: Integrated solid waste management and waste strategies

5.1  Introduction

5.2  Integrated solid waste management

5.3  Planning a waste strategy

5.4  Summary

Section 6: The end of waste and the cycle begins again

Glossary

References

Acknowledgements

Section 1: Wastes basics

1.1  Introduction

In this text I have assumed that you do not have a background in wastes management, and that you are studying this material to gain an insight into the methods available to treat wastes and the environmental impacts of the treatment options.

In the past, waste management was almost exclusively concerned with disposing of wastes. In effect it was a logistics issue – what is the most effective way of collecting the waste, transporting it to a landfill site and depositing it in the site?

For many reasons, which I will discuss in this text, this is no longer the case and it is better to think in terms of ‘resource management’ rather than ‘waste management’. In other words, this text is asking the question:

How can we take products that one sector no longer needs and make them into useful resources for another sector?

With this question in mind, the text explores what waste is and the technologies for managing wastes, and considers the impact that waste and its management has on people’s health. It explores waste policy and practices in different countries, and finally looks at how different waste processes can be combined in the process of ‘integrated solid waste management’.

The self-assessment questions (SAQs) located throughout the text will help you to review and remember what you have read.

1.2  What is waste?

At first sight, this is a simple question, but it is one that we need to answer. A number of years ago I asked my children what waste was, and their answers were:

‘What we produce and throw away: things we don’t need’ (Andrew, aged 11)

‘Rubbish and stuff that people don’t want’ (Christopher, aged 8)

On a more formal basis, the Basel Convention (an international agreement on the exporting of hazardous waste) states that:

‘Wastes’ are substances or objects which are disposed of or are intended to be disposed of or are required to be disposed of by the provisions of national law.

(UNEP, 2011, p. 16)

SAQ 1

Spend a few minutes thinking about this definition and write down your thoughts.

View answer

1.3  Waste categories

All sectors of the economy produce wastes and have their own terms to describe their wastes. Furthermore, different countries classify their wastes in different ways, and have different legal definitions of wastes in general and of the types and categories of wastes. This can be confusing, so to help you through it I have put together a summary of some of the more important terms in the box below.

Categories of waste

Inert waste: Waste that poses virtually no environmental or health threat on disposal. Clean waste ceramic materials and uncontaminated soils would come under this category. Rocks and soils removed during mining and quarrying operations would also be classed as inert wastes (assuming that they ever left the site and entered the waste system).

Hazardous waste: Waste with the greatest potential for causing harm to the environment or public health (e.g. toxic substances, flammable liquids, asbestos, strong acids and alkalis, etc.). Many countries have a formal definition of hazardous waste. For example, the European Union’s List of Wastes (European Commission, 2000) states which wastes are to be classed as hazardous.

Household waste: The waste produced in domestic households and gardens. This is much more than the residual waste that we put out for disposal, because we may reuse a lot of the wastes we generate, dispose of them within the garden, etc. The contents of a kerbside recycling box or a recycling bank in a public car park are classed as ‘household waste’; so are the wastes taken to household waste recycling centres (HWRCs), and so is street litter.

Municipal waste: The definition of this varies from country to country, but it generally covers household waste (see above) plus waste with a similar composition generated by the commercial, government and educational sectors.

Clinical waste or healthcare waste: Waste generated by healthcare activities. The main sources are hospitals, GPs, dentists, vets, laboratories, etc. but healthcare waste can also be produced in the home (by people requiring daily injections, for example). The wastes in this category range from used sticking plasters through to drugs, human organs and body parts. Again, most developed countries have legislation defining and classifying healthcare waste.

Industrial waste: Waste produced by the manufacturing industry, which can cover everything from inert wastes to hazardous wastes. Industrial waste often has a greater potential for recycling than household waste because it is produced in a relatively small number of locations and has a known composition. Furthermore, the producer is directly responsible for its management and bears the cost.

Commercial waste: Waste produced by commercial businesses. This is similar to household waste but tends to contain more paper products. Note that there is a certain overlap between commercial and municipal waste.

Radioactive waste: Waste that undergoes radioactive decay. The military, civil nuclear power stations, hospitals and research laboratories are usually the main producers of radioactive waste. However, radioactive items (such as smoke alarms) are also added to the waste stream at home.

Biodegradable waste: Waste that can be broken down by microbial action (for example paper, card, food waste and garden waste). This is of particular concern because it is the biodegradable components of waste that give rise to landfill gas formation. Many countries (including all EU member states) limit or ban the landfilling of biodegradable wastes. Note that wastes (such as paper) that partially degrade are sometimes termed ‘semi-biodegradable’.

Note that many wastes fall into more than one category. For example, vegetable peelings are both household waste and biodegradable waste, and some types of healthcare waste would also be classified as hazardous.

1.4  Waste quantities and composition

The amount of each type of waste produced by a country will depend on its population and state of development. For example, Figure 1 and Figure 2 present the situation in India (population c.1 080 000 000 in the sample year) and England (population c.51 500 000 in the sample year) respectively.

Figure 1  Waste production in India, 2005 (million tonnes) (Pappu et al., 2007)

View description

Figure 2  Waste production in England, 2008 (million tonnes) (Defra, 2011a)

View description

SAQ 2

Using Figures 1 and 2, comment on the differences between the two sets of data and suggest reasons for the differences.

View answer

The composition of a given waste stream is highly dependent on the process that gave rise to the waste. To take a couple of obvious examples, I would expect the waste from a quarrying operation to consist mainly of rubble and soil, whilst the waste produced by an administrative office complex might contain high proportions of paper.

1.5  Household wastes

For the remainder of this section I will be concentrating on household waste, and have adopted the following broad definition:

The waste produced in domestic dwellings as part of normal day-to-day living.

Note that, as stated previously, this covers much more than the waste deposited in dustbins. For example, it also includes:

materials placed in household recycling bins/boxes

materials taken to recycling banks in public places

wastes taken to household waste recycling centres

litter and street sweepings.

Household waste is one of the more interesting waste streams because it contains everything that people have used and want to throw away. From the waste industry’s point of view it is also the most challenging category of waste to manage, because:

it is generated in a very diffuse form – at every domestic address in the country

it is difficult to control the materials that enter this waste stream

there is often little or no financial incentive for householders to reduce the amount of waste they produce (except in countries – such as Germany – where people are charged for what they leave out for collection by the waste disposal authorities)

there would be a major outcry (certainly in developed countries) if the collection service failed for any reason.

SAQ 3

Many factors control the amount of waste a household produces and the composition of this waste. Make a list of the factors that you think are important.

View answer

The composition of household waste varies widely from country to country. As an example, Table 1 presents data on household waste composition in India and Wales.

Table 1 Household waste composition in India and Wales

(Sharholy et al., 2007; Burnley et al., 2007)

SAQ 4

Account for some of the differences between the household waste composition in India and Wales, as shown in Table 1.

View answer

1.6  Waste policy and regulation

Policy and legislation depend on how developed a particular country is and on whether geographical constraints restrict the options for waste management. Having said that, the following features are common to many individual countries or groups of countries.

The need to manage wastes to minimise any harm to human health or to the wider environment.

The application of a ‘waste hierarchy’ to define priorities for waste management. Hierarchies vary, but generally follow this structure:

reduction

reuse

recycling

recovery

disposal.

A reduction in less-sustainable waste disposal methods (in particular landfill).

General encouragement of the sustainable use of resources.

The licensing of all stages in the waste management industry, and regulation by an independent authority.

Look at any country’s waste policies and you will probably find a general commitment to reduce the environmental impact of waste treatment. You will almost certainly find a commitment to reduce waste and increase the recycling and recovery of wastes. The policies will also reflect the degree of development of the country. For example, Kampala – the capital city of Uganda – has an aim (not fully met in 2012) of collecting all the city’s municipal waste. In contrast, Germany has the aim of virtually eliminating landfill by 2020 through maximising the recovery of materials and energy from waste.

1.7  Waste reduction and reuse

It may seem rather obvious, but the only reason we have wastes to manage is that society as a whole (including you and me) generates waste in the first place. Going back to pre-history, our nomadic ancestors produced virtually no waste at all, so waste was not a problem for them. Whilst it can be tempting to advocate a return to this golden waste-free age, most of us would not be happy to reject the last 5000 years of progress that humanity has achieved.

Having said that, waste reduction and the reuse of waste can help to minimise the quantities of waste that need to be treated.

Waste reduction means minimising the quantity of wastes generated in the first place, and is firmly at the top of the wastes hierarchy that I referred to in the previous subsection. In industry this may mean adjusting production processes to avoid unwanted by-products. Equally, it could mean altering manufacturing and assembly processes to reduce the number of ‘offcuts’ produced, or improving quality control to reduce rejection rates.

Reuse simply means using a product more times than intended by the manufacturer without the need for reprocessing. In a domestic situation this could involve either extending its original purpose (e.g. reusing a plastic carrier bag) or finding a new purpose for it (e.g. making an old piece of clothing into a cushion).

The