[Effect of Aeration Strategies on Emissions of Nitrogenous Gases and Methane During Sludge Bio-Drying]

The data on nitrogen gas (NH3, N2O, NO) emissions during sludge bio-drying process in China is scarce, especially NO due to its unstable chemical property. In this study, effect of two aeration modes on emissions of methane and nitrogenous gas was compared during the continuous aerated turning pile sludge bio-drying process at full scale. In these two aeration strategies, the one currently used in the plant was set as the control, and the other 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 results showed that the aeration strategy used in the test could not only obviously accelerate the rate of sludge drying (the moisture contents of the test and the control were 36.6% and 42% on day 11) , but also had a better drying performance (the final moisture contents of the test and the control were 33.6% and 37.6%, respectively) and decreased the ammonia cumulative emission by 5%, (ammonia cumulative emission of the test and the control were 208 mg x m(-3) and 219.8 mg x m(-3), respectively). Though a lower accumulated emission (eCO2) of greenhouse gas in the test at 3.61 kg x t(-1) was observed than that of the control (3.73 kg x t(-1) dry weight) , the cumulative emission of NO in the test at 1.9 g x m(-2) was 15. 9% higher than that of the control (1.6 g x m(-2)).