采用活性污泥富集与回收废水中碳源的实验研究

以活性污泥为吸附剂，研究了城市污水中的有机物的强化富集与有效回收的方法与参数.在连续运行模式下，活性污泥对废水中的有机物具有较好的富集效果，COD平均吸附率达到63%，且约50%的溶解性碳源分布在细胞外部，在温和条件下就能被解吸；对氮、磷的吸附效果差异较大，磷的吸附量可达76%，对氮的吸附量较小，氨氮吸附率仅13%.同时，实验还研究了常规 (pH=7.5, 20℃)、加热（pH=7.5, 60℃）和碱性加热（pH=11, 60℃）条件下，污泥水解对有机物、氮和磷的释放情况.结果表明，碱性加热条件更有利于碳源的释放，水解24 h后，挥发性悬浮固体（VSS）对COD的释放率达到了320 mg/g；但氮、磷的释放量有限，释放率（水解8 h，稳定）分别为18 mg/g和2 mg/g.利用活性污泥对污染物的吸附与解吸作用，能够实现废水中碳源的回收，且回收碳源中氮、磷浓度低，对回收碳源的再利用效果影响较小.

Harvest of the Carbon Source in Wastewater by the Adsorption and Desorption of Activated Sludge

The carbon source in municipal wastewater was adsorbed by activated sludge and then harvested through the hydrolysis of activated sludge. Results indicated that activated sludge had high absorbing ability towards organic carbon and phosphorus under continuous operation mode, and the average COD and TP absorption rate reached as high as 63% and 76%, respectively. Moreover, about 50% of the soluble carbon source was outside of the sludge cell and could be released under mild hydrolysis condition. Whereas the absorbed amount of nitrogen was relatively low, and the removal rate of ammonia was only 13% . Furthermore, the releases of organic carbon, nitrogen and phosphorus from the sludge absorbing pollutants in the wastewater were studied. By comparing different hydrolysis conditions of normal (pH 7.5, 20 degrees C), heating (pH 7.5, 60 degrees C) and the alkaline heating (pH 11, 60 degrees C), the last one presented the optimum hydrolysis efficiency. Under which, the release rate of COD could reach 320 mg/g after 24 hours, whereas nitrogen and phosphorus just obtained low release rates of 18 mg/g and 2 mg/g, respectively. Results indicate that the carbon source in wastewater could be harvested by the adsorption and desorption of activated sludge, and the concentrations of nitrogen and phosphorus are low and would not influence the reuse of the harvested carbon source.