The composting by trenching and open windrow composting methods require very large area. The process is laborious and time consuming. In large cities the larger area may not be available and therefore mechanical composting is adopted which is very fast mechanical devices are employed in turning the solid waste undergoing composting. The stabilization of the wastes takes only about 3 to 6 m days.
The operation involves
(1) Reception and refuse (2) segregation
(3) Shredding (4) Stabilization (5) Marketing the humus.