Emissions of greenhouse gas and ammonia from the full process of sewage sludge composting and land application of compost

There is a great uncertainty of greenhouse gas( GHG) reduction and nitrogen conservation from the full process of sludge composting and land application of compost in China due to the lack of emission data of GHG such as N2O and CH4and ammonia( NH3). The purpose of this study is to get emission characteristics of GHGs and NH3from the full process with on-site observation.Results showed that the total GHG emission factor from full process of the turning windrow( TW) system( eCO2/ dry sludge,196. 21kg·t- 1) was 1. 61 times higher of that from the ATP system. Among the full process,N2O was mostly from the land application of compost,whereas CH4mainly resulted from the sludge composting. In the sludge composting of ATP,the GHG emission equivalence of the ATP( eCO2/ dry sludge,12. 47 kg·t- 1) was much lower than that of the TW( eCO2/ dry sludge,86. 84 kg·t- 1). The total NH3emission factor of the TW( NH3/ dry sludge,6. 86 kg·t- 1) was slightly higher than that of the ATP( NH3/ dry sludge,6. 63 kg·t- 1).NH3was the major contributor of nitrogen loss in the full process. During the composting,the nitrogen loss as NH3from both TW and ATP was nearly the same as 30% of TN loss from raw materials,and the N and C loss caused by N2O and CH4were negligible. These results clearly showed that the ATP was a kind of environmentally friendly composting technology.