There are three basic types of centralized composting processes or methods.
In-Vessel Method
The organic material is composted inside a drum, silo, agitated bed, covered or open channel, batch container or other structure. The process conditions are closely monitored and controlled and the material is aerated and mechanically turned or agitated.
Aerated Static Pile Method
Involves forming compostable materials into large piles, which are aerated by drawing air through the pile or forcing air out through the pile. The pile is not turned.
Windrow Method
Compostable material is formed into elongated piles, known as windrows, which are turned mechanically on a regular basis.