What Is Integrated Waste Management

There are many different ways of dealing with waste in order to minimise risks to public health and the environment. For many years waste management was carried out in a piecemeal, relatively unplanned way. More recently, experience has shown that a more sustainable approach to society's uses of resources and management of wastes is needed.

The term integrated waste management (IWM) is often used to describe an approach in which decisions on waste policies and practices take account of waste streams, collection treatment and disposal methods, environmental benefits, economic optimisation and social acceptability.

Integrated Waste Management systems combine waste streams, waste collection, treatment and disposal methods, with the objective of achieving environmental benefits, economic optimisation and societal acceptability.

Overview of Waste Management Options: Their Efficacy and Acceptability Principles of IWM

IWM allows decisions to be based on best practice and cost transparency. The smaller the amount of waste put into the system the lower the costs apportioned to the generator of that waste. This provides incentives for users to reduce the amount of waste they generate.

• IWM considers all options (collection, recycling, composting, biogasification, energy recovery and landfilling) for the entire municipal solid waste stream -not simply sub-streams

• shared responsibility - manufacturers, distributors, retailers, consumers and other stakeholders have a responsibility to support IWM. Each group is responsible for the correct management of wastes they create

• three criteria should be considered - environmental effectiveness, economic efficiency, social acceptability

• flexible application for different communities and regions

• transparent costs for waste management

• market-oriented recovery and recycling

• appropriate economies of scale

• continual assessment to accommodate changes in quantity and quality of the waste stream

IWM is a concept which has different local applications and which depends on many variables such as the composition of the waste stream, infrastructure, markets for recyclables, budgets, local legislation and land availability. IWM seeks the best options for waste management, with an emphasis on evaluating all available strategies to deliver more sustainable systems.

There are several possible aspects to this integration. Upstream collection and handling should be integrated with downstream treatment, processing and disposal. The management of municipal solid waste (MSW) may be integrated with industrial and commercial waste streams. The collection of materials for recycling or composting needs to be integrated with markets for products for the system to be sustainable. A further tier of integration rests at the policy level, enabling the development of new waste management facilities. This calls for collaboration between planning authorities, industry and the public.

The details included in the IWM concept vary around the world. In California, for example, IWM specifically includes public education and outreach programmes, along with efforts to foster markets for recyclables. In South Africa, IWM aims to integrate and optimise waste management in order to maximise efficiency and minimise environmental impacts and financial costs of waste and improve the quality of life of its citizens.

The term IWM does not describe or prescribe the actual techniques applied to deal with a particular waste stream, but refers to the overall approach to considering how best to manage wastes. An integrated approach does not mean that a community or region would implement all waste management techniques, only that they are all considered.

The variable nature of waste means that no single option (apart from landfilling, and there are sound reasons for wishing to reduce dependence on final disposal) could ever deal with an entire waste stream. Some waste is suitable for recycling, some for biological treatment, some for energy recovery. Policies can provide a framework where more or less waste might be channelled in particular directions, but there are limits, beyond which each option becomes technically unreasonable, environmentally adverse, economically inefficient and socially unacceptable. The upper limits to recycling are seldom higher than 60%, while the organic content of waste (which limits scope for biological treatment) rarely exceeds 70%. The proportion of municipal solid waste which is combustible is often less than 60%.

Operations within any waste management system are clearly connected. For example, the type of sorting scheme introduced in an area will affect the ability to recover materials, or produce marketable compost. Many effective recycling programmes deliver a residual waste which becomes more suitable for energy recovery. Landfilled waste can be reclaimed, and landfill gas recovered.

An integrated system would include an optimised waste collection system and efficient sorting, followed by one or more of the following options:

• materials recycling will require access to reprocessing facilities

• biological treatment of organic materials will ideally produce marketable compost and also reduce volumes for disposal. Anaerobic digestion produces methane that can be burned to release energy

• thermal treatment [such as incineration with energy recovery, burning of Refuse-Derived Fuel (RDF) and burning of Paper and Plastic-Derived Fuel (PPDF)] will reduce volume, render residues inert and should include energy recovery

• landfill can increase amenity via land reclamation but a well-engineered site will at least minimise pollution and loss of amenity

To manage all solid waste arisings in an environmentally effective way requires a range of the above treatment options.

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