[1] In-vessel composting systems can consist of metal or plastic tanks or concrete bunkers in which air flow and temperature can be controlled, using the principles of a "bioreactor".
This technique is generally used for municipal scale organic waste processing, including final treatment of sewage biosolids, to a stable state with safe pathogen levels, for reclamation as a soil amendment.
The advantage of using roll-off waste dumpsters is their relatively low cost, wide availability, they are highly mobile, often do not need building permits and can be obtained by renting or buying.
Evaluation is ongoing with regard to the health risks associated with compost derived from sewage biosolids—including identifying safe levels of contaminants such as PFAS ("forever chemicals").
A more advanced systems design is able to limit the odor issues considerably, and it is also able to raise the total energy and resource output by integrating in-vessel composting with anaerobic digestion.