Biodegradable plastic reduces ammonia emission during composting

Ammonia is the greatest nuisance odor compound among the exhaust gases that evolve during the composting process, in which raw materials with high con centrations of nitrogen, such as wastewater sludge, are decomposed. In the present study, a reduction of NH3 emission during composting of wastewater sludge was tried by mixing biodegradable plastic into composting raw materi al. Biodegradable plastic acts as a "reserve acid", i.e. it is not acid its elf but degrades and releases acid intermediates during the composting prog ress. In this study, the plastic neutralized and fixed the NH3 generated du ring the organic matter decomposition in the composting material, and made it possible to reduce NH3 emission drastically during the composting of the wastewater sludge. (C) 2000 Elsevier Science Ltd. All rights reserved.