Study On Emission Characteristics And Synergetic Control Of Nitrogenous Gas In Sludge Disposal Process

Biological sludge drying and compost as an effective means of sludge disposal,The data of nitrogen gas(NH3、N2O、NO) emissions during sludge bio-drying process in China is scarcity, especially NO due to its unstable chemical property,emissions in the process of disposal of toxic gases also jeopardizing the health of employees. In this study, effect of two aeration modes on methane and nitrogenous gas emission was compared during the continuous aerated turning pile sludge bio-drying process at full scale. and different additives in the process of sludge compost(zeolite,DMPP) nitrogen loss and the impact of greenhouse gas emissions, so as to provide scientific basis for optimization of sludge composting process parameters.Major results were listed as following:1. Results showed that in these two aeration strategies, the current used in the plant was set as the test in which the aeration was used for oxygen supply,pile temperature control,and moisture removal in the start-up, middle and final stages, respectively. the aeration strategy used in the test could not only obviously accelerate the rate of sludge drying,e.g. within 11 days, the moisture contents of the test and the control were 36.6%、42%,but also had a better drying performance and decreased ammonia cumulative emission by 5%,e.g. the final moisture contents of the test and the control were 33.6% and 37.6%, respectively; ammonia cumulative emission of the test and the control were 208 mg/m3 and 219.8 mg/m3,respectively. Though a lower accumulated emission of greenhouse gas in the test at 3.605 kg e CO2/t DS was observed than that of the control at 3.726 kg e CO2/t DS,the cumulative emission of NO in the test at 1.9 g/m2 was 15.9% higher than that of the control at 1.6 g/m2.2.The initial moisture content of about 65%, the whole pile turning period is shortened to 14 days, achieve the purpose of drying(down to below 45% moisture content),reduce 60% of the ammonia emission,due to the accumulation of aeration time is shortage,the microbial reaction is not completed. Cause the sludge reduction effect and the remaining two groups compared to the slightly difference.3.Add to wet weight 1% zeolite powder can reduce the cumulative emissions of greenhouse 5% composting process,decreased ammonia volatilization and accounted for 37% of total nitrogen loss of initial 2.9%; add the cumulative emissions of nitrification inhibitors can reduce N2 O,but increased CH4 emissions of greenhouse gas equivalent higher than that of control group. increase ammonia cumulative emission by 13.7%, nitrogen loss compared with the control group increased 6%.