Experience in India
Ten mechanical compost plants were set up in India during 1975-80 under the Central Scheme of Solid Waste Disposal. These plants used different flowsheets. NEERI evaluated the performance of 7 of these mechanical composting plants during 1980-82. The studies revealed :-
· Large storage hoppers are not needed.
· The waste characteristics indicated that magnetic separators were inefficient at the concentration of metals in Indian municipal solid waste
& need not be provided.
· Revolving drum mixers were counter productive and need not be provided.
· Covering of windrow area is not required as the plants are normally shut down during monsoon for annual repairs.
· Artificial aeration under Indian conditions does not reduce composting time and hence need not be provided.
· It is preferable to first stabilise the raw material and then subject it to picking and size reduction. This will require same windrow area, and improve efficiency of picking and size reduction.
· Composting should not be considered as a commercial venture but should be treated as a processing method and the sale price of compost fixed accordingly.
· In case the plants have to be set up by private agency, this aspect should be kept in view while entering into agreement.
14.6.3 Composting Plants for Indian Municipal Solid Waste
The Municipal Solid Waste in Indian urban centres has a favourable C/N ratio of around 30 and is amenable to composting. The farmers and horticulturists are also accustomed to the use of farmyard manure and hence may adopt compost prepared from municipal solid waste. While setting up a municipal scale mechanical compost plant the following steps need to be taken.
