Carbon Turnover and Ammonia Emissions during Composting of Biowaste at Different Temperatures
- Ylva Eklinda,
- Cecilia Sundberg *b,
- Sven Smårsb,
- Kristin Stegerc,
- Ingvar Sundhc,
- Holger Kirchmanna and
- Håkan Jönssonb
- a Dep. of Soil Sciences, Swedish Univ. of Agricultural Sciences, P.O. Box 7014, SE-750 07 Uppsala, Sweden
b Dep. of Biometry and Engineering, Swedish Univ. of Agricultural Sciences, P.O. Box 7032, SE-750 07 Uppsala, Sweden
c Dep. of Microbiology, Swedish Univ. of Agricultural Sciences, P.O. Box 7025, SE-750 07 Uppsala, Sweden
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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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