Air bag bioreactor to improve biowaste composting and application

Abstract A novel bioreactor (air bag bioreactor) was constructed for composting biowaste, waste gas management and ammonia recycling. Laboratory scale composting was successfully conducted in the air bag bioreactor, in which the oxygen concentration fluctuated between 14% and 21%, while the carbon dioxide concentration fluctuated between 0% and 7%. Daily ammonia emission was observed in the primary stage of the composting process, while nitrate generation was observed in the later stage of composting. Ammonia recycling was successful in the air bag bioreactor, resulting in the nitrate concentration increasing from 62 mg/kg to 1157 mg/kg, while the ammonia concentration periodically decreased to a low level due to intermittent pumping and exhaustion of waste gas. A pilot scale bioreactor using the novel design was successfully constructed and operated in a rural village.