Municipal solid waste (MSW) is collected in roadside bins and Municipal Corporation collects it infrequently. Solid waste generation ranges between 0.6 to 0.8 Kg/capita/day and the waste generation growth rate is 2.4% per year. Fairly around 40% of the generated waste remains either at collection points or in streets [2]. It is a common practice to burn this waste in open. Residential waste is usually collected and transported directly to a landfill site. However, these landfills are not designed properly causing problems like incomplete decomposition of MSW, methane production and leach ate contamination of groundwater. At the collection points, different types of waste are not collected separately, and there is no proper waste collection system either. Waste is dumped un-segregated and collected by three methods: 1) hauled container system, 2) stationary container system and 3) bull carts.
In Pakistan, the containers are mostly transported from one place to another with help of a truck or tractor, which is overflowing and not covered properly. The waste spills out of the container and a lot of it falls in the streets before reaching the landfill site. Similarly, in certain areas bull and donkey carts are used to collect the MSW. The cart goes from street to street picking up the waste and is again not a proper system for waste collection.
Disposing Techniques:
The solid waste disposal process in Pakistan is one which is least developed. 3 primary ways of disposing waste are in practice – landfill, size reduction and screening. Residential wastes are usually collected and transported directly to a landfill site. When new landfills are being planned, the most important issue is to find a location that is acceptable to the public and to local regulatory agencies. In the management of existing landfills, the major concern is to ensure that proper operational procedures are followed carefully and routinely. In the past, the term sanitary landfill was used to describe landfill where the waste was covered at the end of each day’s operation. Today, sanitary landfill refers to an engineered facility, designed and operated to minimize public health and environmental impacts. Problems with landfills are subject to biological and physical factors in the environment. As a result, they change over time and may cause the several problems including leach ate contamination of groundwater; methane production; incomplete decomposition and separation.
The separation of solid waste components is one of the most positive and effective ways to recover and reuse materials. Size reduction is a process in which collected waste materials are mechanically reduced in size. In practice, the terms shredding, grinding, and milling are used interchangeably to describe mechanical size reduction. The objective of size reduction is to obtain a final product that is reasonably uniform and considerably reduced in size in comparison with its original form.
In addition, screening is used to separate mixtures of materials of different sizes into two or more sizes by using screening surfaces. Many new technologies have been developed to solve MSW problems, but unfortunately, these technologies are either too sophisticated or expensive for use in developing countries like Pakistan.
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