COMMUNITY LEVEL COMPOSTING OF MUNICIPAL SOLID WASTE

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RISE-AT Waste Management Factsheet 2 Community Level Composting of Municipal Solid Waste Method How This Is Achieved Advantages Disadvantages No Separation No separation occurs. The Low cost Produces a very contaminated contaminated waste compost product, which will be stream is composted as it is delivered to the site. The final compost product can be sieved to remove large contaminating items at the end of the composting process. Can be used as a method to stabilise the waste before it is added to the landfill site. Could be used as a daily or final cover for the landfill site. (Particularly useful where soil cover for landfill is in short supply and needs to be excavated and transported to the site). difficult to sell and may cause health hazards if used on crops. May operate successfully if only waste collected from markets is used, as this should have a high organic content. The two recommended methods of separation are:- 1) Source Separation by Householders – This is the ideal option and is operated successfully in many countries. It will produce the best quality compost and simplify the preprocessing operations that are performed at the composting site. The key to successful implementation is educating the community on what to separate and motivating them so that they will bother to do it. This can be encouraged with financial incentives, such as increasing the collection fees for those who do not separate the waste. 2) Hand Separation at the Composting Site - This is the best option if source separation cannot be achieved in the community, It requires several people to sort the waste by hand and can produce a reasonably clean stream of organic materials, the quality of the sorting depending on the number of people sorting the waste and the time taken. It is however impossible to completely remove all contaminants by hand separation and the compost will have more contamination than that produced from source separated waste. 4 - SITING <strong>OF</strong> THE <strong>COMPOSTING</strong> FACILITY The compost system needs to be positioned on open land to allow sufficient room to establish and manipulate the compost piles. It should be a site that has:- i) Suitable access for transportation of the waste to the site. ii) A ‘buffer area’ between the site and nearby land-users, this is to minimize the nuisance of waste and compost odors. iii) Appropriate soil for absorption or collection of leachate. iv) Room to accommodate the amount of material that requires composting plus room to store finished compost material. v) A level, well drained surface. Page 6
RISE-AT Waste Management Factsheet 2 Community Level Composting of Municipal Solid Waste vi) vii) Easy access to a source of water for wetting the compost piles. Adequate fencing and control to prevent it from becoming an open dump site and to keep unauthorized waste pickers out of the site. It may be appropriate to have the compost facility close to the landfill site. This will allow ease of transportation of rejected inorganic waste to the landfill and lower quality compost can be used as cover material at the landfill site. 5 – DEFINE PRE-PROCESSING OPERATIONS Mechanical pre-processing is often the most costly part of a composting system, as well as the most vulnerable to breakdown. Therefore, if you are looking for a low cost, simple system it is recommended that pre-processing is minimized and manual labor is used wherever possible. Preprocessing can be split into two parts, separation of the compostable parts of the waste and chopping of the waste to ensure it is a suitable size for composting. SEPARATION – As discussed previously, the better the separation the better the quality of compost produced. Even if source separation can be organized, there is still a requirement for some level of sorting at the composting site, (although this will be a much smaller operation than if unsorted waste is delivered). Methods for sorting the waste by hand are:- 1) For a low cost operation, the waste can be delivered to a sorting area, which consists of a concrete floor or paved area. Here the waste can be sorted by operators who pick out any recyclable goods or residues that cannot be composted. The sorting can be organised so that one person delivers the waste to the sorting area, a number of people sort the waste and one person takes the sorted organic waste to the next preprocessing stage. 2) The waste can be placed on a moving belt and transported past stationary workers who hand pick the inorganic and uncompostable materials from the waste stream. The speed of the belt should not exceed 15m/min and its width should not be more than 1m, unless it is being worked from both sides. The belt should be flat and spillage prevented by retaining boards of wood or metal along both sides. The belt should be the height above the floor equal to the average elbow height of the workers. Boxes or baskets should be provided for workers to deposit the different waste fractions picked from the belt. The length of the belt and number of workers depends on the amount of waste being sorted and the amount of contamination in the waste stream. • It is recommended that workers wear gloves, adequate clothing and safety glasses to protect against injury from sharp objects. These should be supplied by the site management and rules that require the wearing of the safety items during all sorting activities should be strictly enforced. Page 7
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COMMUNITY LEVEL COMPOSTING OF MUNICIPAL SOLID WASTE

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