Proper waste management in developing countries is increasingly becoming popular, especially the use of engineered sanitary landfills. In this study, the classification, design, and operation of sanitary landfills are stated and suggestions made. The landfills were classified in accordance to waste type and population size. Leachate control mechanisms were put in place in a bid to avoid surface and underground water pollution. Several liner materials such as clay and geotextile material are recommended to avoid leachate perforating into the ground. Waste management is encouraged to be done through the cell system which must be compacted and covered on a daily basis. Resource recovery of biogas for power generation is recommended to recovery value from the waste as well as to lower landfill operation costs. Post-closure monitoring of the landfill must be done and recreation centers can be developed on the landfill as a rehabilitation strategy. Land filling is essential for proper waste management and is also governed by local acts.
TopIntroduction
Proper waste management in developing countries is becoming critical in developing countries hence the need for properly engineered sanitary landfills. Land filling is defined as placing solid and semi-solid wastes on the ground, compacting and covering the waste with suitable materials to isolate it from the environment. Sanitary landfills have to be properly engineered and be able to accommodate a community waste quantity for a certain time period without compromising the resource expenditure and environmental health (Environment Agency, 2004). Various factors come into play in planning a sanitary landfill site construction and location. A sanitary landfill site should be planned for a long period of use in view of necessary investment in infrastructure and environmental protection measures (Ministry of Environment, 1999). Experience shows that it is economic to design a disposal site to operate for a minimum of 25 years. In order to meet these requirements sanitary landfills must both be affordable and environmentally acceptable, they must suit different needs and situations in a scientifically developed way. A village with a population of 100 people, for example, cannot be expected to have the same waste disposal needs, or meet the same set minimum requirements, as a city with a population of 1,000,000. A system for classifying sanitary landfills is therefore needed, as a basis for setting and applying the appropriately graded minimum requirements. This system has to recognize the inherent qualities and differences which characterize any sanitary landfill operation, i.e. the types of waste involved, the size of the waste stream and the potential for significant leachate generation. The sanitary landfill classification system will include waste type, size of operation and leachate generation capacity. In particular, the potential for significant leachate generation, the main cause of water pollution from sanitary landfills has to be preferentially considered.
This study focused on sanitary landfill classification systems are to be considered for waste disposal situations and needs in terms of combinations of waste type, size of waste stream and potential for significant leachate generation Furthermore, the sanitary landfill classification as the basis for setting standard requirements for the cost-effective selection, investigation, design, operation and closure of sanitary landfills.
Classification of Sanitary Landfills According to Waste
Using the classification system, sanitary landfills are grouped according to the type of waste involved, the size of the waste stream, and the potential for significant leachate generation (EPA Victoria, 2009). Note that the sanitary landfill classification system cannot address factors specific to a particular site, such as the sensitivity of the receiving environment. Such factors are addressed during site selection, investigation and environmental impact assessment, where any critical factor would be identified (Shah, 2000). Before a sanitary landfill can be developed or permitted for continued operation, it must to be demonstrated that any adverse environmental impacts can be addressed in the sanitary landfill design and operating plan.
Sanitary landfills can further be divided by the toxicity of waste to be accommodated. Conveniently, waste types can be grouped into two classes which are general and hazardous waste (EPA Victoria, 2009). Based on this, sanitary landfills can therefore also grouped into sanitary landfills suitable only for general waste, such as domestic refuse, and sanitary landfills for hazardous waste, generated by households but still toxic. This study mainly focused on municipal solid waste (MSW) which is general non-hazardous waste stream.