Think back to previous study sessions and remind yourself what you understand by the following terms:
Waste reduction means avoiding producing waste in the first place. In manufacturing industry, it is about using less raw materials to make a given product. In the home, waste reduction could include avoiding buying over-packaged products.
Reuse happens when something is used more than once for its original purpose – perhaps refilling a drinks bottle with water.
Recycling is the reprocessing of materials recovered from waste so that they can be used as raw materials in manufacturing processes, for example melting of glass bottles and forming them into new bottles. You may also have mentioned composting which is classified as a form of recycling.
By now you are familiar with the waste hierarchy, which is shown again in Figure 11.1. In the past few study sessions, we have discussed all the options in the hierarchy from the most desirable (reduction) to the least desirable (disposal).
Unfortunately, many towns and cities are not able to follow the waste hierarchy and the only option used is disposal. Much of the waste is never collected (it is dumped or burned) and even where it is collected, most of the waste is taken to a landfill that has no means of controlling pollution from the site. Case Study 11.1 illustrates this situation.
Case Study 11.1. Waste management: an example of current practice
In 2011, our example town had a population of around 160,000; this had grown to 200,000 by 2014. Solid waste generation in 2011 was 88 metric tonnes per day with 87% of this being waste from households.
A total of 25% of households deposited their waste in communal containers that were then taken to landfill; 51% used disposal pits, their own backyards or open dumping of waste in public spaces; 22% burned their waste in public open spaces; and the remaining 2% of households had waste collected by private sector organisations. There is no formal system for collecting wastes for reuse or recycling.
Waste management is the responsibility of the municipality’s Social and Economic Department who employ 33 waste workers. The department has one tipper lorry for waste collection purposes and ten metal bins for commercial waste storage, each with a capacity of 4 m3 that are placed randomly in residential and commercial areas. The budget for waste is less than 1% of the total municipal budget. Staff wages take up 90%, and the remainder is spent on fuel, maintenance and other running costs (Getahun et al. 2012.
The situation here is typical of many towns in low-income countries. This session looks at how towns like this one can adopt the principles of Integrated Solid Waste Management to move their waste management systems further up the hierarchy and reduce the risks of damaging people’s health and the environment.
Integrated Solid Waste Management (ISWM) can be defined in many ways, but it is probably best to think of it as a way of using a combination of waste management techniques to treat the different types of waste in ways that are environmentally, financially and socially sustainable. ISWM should be based on the waste hierarchy and focus on using the 3 Rs while finding a suitable way of dealing with the remaining waste. It also depends on collaboration among all the organisations and individuals involved in waste management.
Van de Klundert and Anschütz (2001) explain that the ISWM concept is built upon four basic principles:
- Equity: the allocation of resources, services and opportunity to all segments of the population according to their needs. In waste management, this means that everyone has a right to be served by a waste management system that protects their health and the environment. Pollution travels and doesn’t respect kebele or area boundaries, so if one area is neglected, a much larger area can suffer.
- Effectiveness: the waste management methods used must meet the overall aims of any waste plan and meet the needs of the people. At the very least, effectiveness means that all the waste is collected and disposed of in a safe way. Once this has been achieved, higher-level aims such as maximising waste recycling and composting should be addressed. Again, a scheme is only effective if it covers the whole district or city.
- Efficiency: in general, efficiency means increasing output for a given input, or minimising input for a given output. An efficient waste management system is one that is equal and effective while making the best use of the resources available (staff effort, use of equipment and cost).
- Sustainability: for a project, programme or other activity to be sustainable it must be effective and last a long time. To achieve sustainability social, environmental and economic factors must be considered. Sustainability of the waste management system can be achieved if it is appropriate to the local conditions and can continue in the long term by using the human, financial and material resources available in the area. It should also be environmentally sustainable in that it minimises the use of non-renewable natural resources (such as oil) and doesn’t lead to long-term environmental problems that will be left for later generations to address.
Which of the following waste management systems meet the four conditions of ISWM?
- Waste is collected from households that can pay a weekly fee; those who can’t pay use informal methods of waste disposal.
- A network of communities coordinated by the local administration collect recyclable materials (glass, paper and metals), householders take the remaining waste to communal bins (one per 30 households) which are emptied by the local contractor who takes the waste to landfill.
- Waste is collected from households in well-off areas by charging a weekly fee; in poorer areas, the waste is collected from communal bins by local employees.
- Under a grant from an aid agency that will run for two years, a community’s waste is collected, taken to a transfer station and then driven 20 km to a landfill site that is also funded by the grant.