Floatation of granular sludge and its mechanism: A key approach for high-rate denitrifying reactor

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• 作者：Wei Li ; Ping Zheng ; Junyuan Ji ; Meng Zhang ; Jun Guo ; Jiqiang Zhang ; Ghulam Abbas
• 关键词：High-rate DAC reactor ; Working performance ; Granular sludge floatation ; Floatation mechanism
• 刊名：Bioresource Technology
• 出版年：January, 2014
• 年：2014
• 卷：152
• 期：Complete
• 页码：414-419
• 全文大小：1077 K

文摘

A high-rate denitrifying automatic circulate (DAC) reactor has been developed recently, and it is promising to become an alternative in nitrogen removal from wastewaters. However, the performance of DAC reactor was disturbed by the floatation of granular sludge at high-loads. The results showed that: the floatation of granular sludge led to a serious biomass washout and a sharp decrease of biomass concentration. The floatation of granular sludge was ascribed to a low sludge density originated from the holdup of gaseous products. The average density and average gas holdup ratio of floated granular sludge were 913 kg m^鈭? and 11.8% (by volume), respectively. The floatation of granular sludge could disappear by releasing gas when sludge was in the state of elastic expansion, but it would become worse by holding gas when it entered the plastic expansion state. The plastic expansion of granules was significantly correlated with the less content of extracellular polymeric substances.