Bangalore method

1. This is an anaerobic method conventionally carried out in pits.
2. Initially, a layer of coarse municipal solid waste is placed at the bottom of a pit to a depth of 15 to 25cm and is made 7.5cm thicker for 25cm width towards both the edges of the pit. Night soil is put in the depressed portion to a thickness of 5cm and the elevated edges prevent it from draining to the side.
3. A layer of solid waste is put on top so that the night soil layer is sandwiched between the two layers of municipal solid waste. Solid waste and night soil are put in alternate layers till it rises to a height of 30cm above the pit edge.
4. The final layer of solid waste is at least 25 to 30cm thick. The top of the deposited material is rounded off to avoid rain water entering into the pit.
5. After 4 to 6 months of decomposition the material is stabilized and is taken out and used as compost.

Indore method

1. The Indore method of composting in pits involves filling of alternate layers of similar thickness as in the Bangalore method.
2. However, to ensure aerobic condition the material is turned at specific intervals for which a 60cm wide strip on the longitudinal side of the pit is kept vacant.
3. The first turn is manually given using long handed rakes 4 to 7 days after filling. The second turn is given after 5 to 10 days. Further turning is normally not required and the compost is ready in 2 to 4 weeks.
4. Aerobic composting of solid waste and night soil can be carried out in windows of more or less the same dimensions as the pits.
5. However, aerobic composting in windows on more commonly used while composting municipal solid waste alone.