Carbon Turnover and Ammonia Emissions during Composting of Biowaste at Different Temperatures

• Published in: Journal of environmental quality 2007-09, Vol.36 (5), p.1512-1520
• Main Authors: Eklind, Y, Sundberg, C, Smars, S, Steger, K, Sundh, I, Kirchmann, H, Jonsson, H
• Format: Article
• Language: English
• Subjects: air pollution; Ammonia; Ammonia - analysis; Ammonia - metabolism; biodegradation; Biologi; Biology; Biomass; Bioreactors; Carbon; Carbon - metabolism; carbon dioxide; Carbon Dioxide - analysis; Carbon Dioxide - metabolism; Chemicals; Community structure; Composting; Decomposition; Emission measurements; Experiments; Fatty Acids - analysis; gas emissions; High temperature; Household wastes; Hydrogen-Ion Concentration; Low temperature; Mineralization; NATURAL SCIENCES; NATURVETENSKAP; Nitrogen - metabolism; Oxygen - metabolism; Soil; Soil Microbiology; Studies; Temperature; Time Factors; Waste Management
• ISSN: 0047-2425; 1537-2537; 1537-2537
• DOI: 10.2134/jeq2006.0253

The effects of different process temperatures (40, 55, and 67°C) during composting of source-separated household waste were studied in a 200 L compost reactor at an oxygen concentration of 16%. The overall decomposition measured as carbon mineralization, decomposition of different carbon constituents, and the dynamics of nitrogen mineralization and the microbial community, are reported. Ammonia emissions at 67°C were more than double those at lower temperatures, and they were lowest at 40°C. The decomposition rate, measured as CO2 emission, was highest at 55°C. Decomposition of crude fat was slower at 40°C than at 55 and 67°C. The peak in microbial biomass was largest in the run at 40°C, where substantial differences were seen in the microbial community structure and succession compared to thermophilic temperatures. Biowaste composting can be optimized to obtain both a high decomposition rate and low ammonia emissions by controlling the process at about 55°C in the initial, high-rate stage. To reduce ammonia emissions it seems worthwhile to reduce the temperature after an initial high-temperature stage.