| In order to get high quality effluent of municipal wastewater treatment and reduce the space of WWTP, this study choose aerobic granular sludge as core technology. In this research, different cultivation mode of granulation process were studied to get stable granular sludge rapidly and efficiently. The influence of DO and granular structure were studied in the nitrogen removal process of aerobic granular sludge. SBR and HUSB(Hydrolysis Up-flow Sludge Bed)+SBR system were used to cultivate aerobic granular sludge by municipal wastewater. The main conclusions were as follow:(1) Anaerobic plug flow mode, traditional mode and anaerobic mix mode were used in the granulation process. The aerobic granular sludge got under anaerobic plug flow mode had compact structure and smooth surface. The MLSS is 12.0g/L, average particle size is 2.0-3.0mm, and TN removal rate is 96%.(2) The nitrogen remove process in aerobic granular sludge system is built on the simultaneous nitrification and denitrification(SND) theory. Due to the large particle size, DO and subtract transfer were limited in granular sludge. When the DO is 2.5mg/L, effluent TN concentration is lower than 3mg/L. When the layer structure of granular sludge were destroyed, effluent TN increased to 10mg/L.(3) It’s very difficult to cultivation aerobic granular sludge by municipal wastewater without any pretreatment. After 70 days operation, the SBR system didn’t get aerobic granular sludge, and TN removal rate was only 70%. Using HUSB+SBR system, aerobic granular sludge, which particle size was 200-300 um, were discovered in the SBR reactor after 70 days operation. Although flocculent sludge was still dominant in SBR, the effluent TN decreased to 10mg/L, and TN removal rate reached 80%.(4) In the research of using mature aerobic granular sludge to treat municipal wastewater, effluent COD concentration was low than 25mg/L, and effluent TN concentration was 5mg/L. |
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