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Study On N2O Production During Nitrogen Removal With Aerobic Granular Sludge

Posted on:2011-08-11Degree:MasterType:Thesis
Country:ChinaCandidate:J L YangFull Text:PDF
GTID:2121360308471212Subject:Environmental Science
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With the eutrophication question becoming increasingly prominent, how to improve the traditional nitrogen and phosphorus removal efficiency of nitrogen and phosphorus removal process and develop an efficient, energy-saving wastewater treatment has become the hot spot which the sewage nitrogen and phosphorus removal technologies focus on. With the advantages of good settling properties and the resistance to shock loading, aerobic granular sludge stand out from the numerous processes. In recent studies, N2O, as one of the most important greenhouse gas, was produced along with the nitrogen removal processes, and its warming potential was 310 times of CO2, and 23 times of CH4. Biological wastewater treatment process is considered as a potential source of N2O production. Recent studies also shown that N2O were produced from both nitrification and denitrification processes, mainly in the aerobic nitrification phase. Currently, studies on the new technology with the advantages of aeration-saving and carbon source saving demonstrated that N2O was produced during the sewage treatment process. For aerobic granular sludge with the function of nitrogen removal, there are no much reference for the questions, for instance, whether N2O was produced during nitrogen removal, and whether N2O production capacity of the nitrification could be changed by temperature or the type of nitrification.In this paper, using aerobic/anoxic operation mode of the SBR reactor to treat synthetic wastewater, the studies were about nitrogen removal performance, stability, and N2O production from both complete nitrification-denitrification and shortcut nitrification-denitrification. The results showed that aerobic granular sludge with good nitrogen removal performance had good storage stability and the active recovery, at the same time, it also verified the feasibility of commercialization. With good correlation between the conversion of nitrogen concentration, DO and pH changes on value points, it would successfully regulate the operation time and the end of nitrification and denitrification in use of DO and pH value changes, so that shortcut nitrification and denitrification system could be stably operated for a long-term. The statistics showed that the denitrification time escalate by one time, the N2O production would be a double than that produced under real-time control, So N2O production could be able to effectively control and reduce during nitrogen removal process with the application of real-time control strategy. Lower the temperature led to N2O production decreased during the removal process, in anoxic phase, the amount of N2O production was not affected by the temperature drop, while the difference of N2O production during denitrification was caused by the nitrite concentration accumulated during aerobic phase. Under the same condition of in influent ammonia and aeration, N2O emission and dissolved N2O in sludge mixture represent the same trend during nitrogen removal,and N2O production during complete nitrification and denitrification process were more than that during shortcut nitrification and denitrification process,nearly 1.55 times, and the shift ratio of N2O was 1.59times than that of shortcut nitrification-denitrification.
Keywords/Search Tags:N2O, aerobic granular sludge, complete nitrification and denitrification, shortcut nitrification and denitrification, temperature
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