活性污泥快速吸附污水碳源的动力学研究

Dynamics of Quickly Absorption of the Carbon Source in Wastewater by Activated Sludge

为了解不同活性污泥对污水中碳源的吸附机制,探讨利用活性污泥吸附、回收污水碳源的可行性,研究了3种活性污泥(富碳、硝化和反硝化污泥)对城市污水中有机物吸附特征,并采用以Richie速率方程为基础的3种吸附动力学方程对此吸附过程进行了动力学数据分析.在吸附过程的前30 min左右,活性污泥以物理吸附为主,可用Lagergren单层吸附模型表述.富碳污泥的吸附量(COD/SS)最大,约60 mg/g,但吸附速率要较反硝化污泥慢;硝化污泥的吸附速率最小,但吸附容量较反硝化污泥大,约35 mg/g.富碳、硝化和反硝化污泥的拟合参数θ0值分别为0.284、0.777和0.923,说明富碳污泥表面吸附的有机物通过预处理,清洗得最彻底,即富碳污泥对有机物的结合力度最小,有利于被吸附碳源的释放.采用Langmuir模型拟合可知,在此吸附试验条件,有机物浓度是影响污泥吸附量的关键参数,温度影响非常小.本研究分析了不同种类活性污泥对污水碳源的吸附动力学规律,为动力学分析活性污泥的除污机制提供了方法,为利用活性污泥的吸附作用回收污水碳源提供了理论基础.

In this paper,absorption characteristics of organic matter in municipal wastewater by three kinds of activated sludge（carbon-enriching,nitrification and denitrification sludge） were studied,and the absorption kinetic data was checked using three kinds of absorption kinetic equations based on Ritchie rate equation.The objectives of this study were to investigate the absorption mechanism of activated sludge to organic matter in municipal wastewater,and to identify the possibility of reclaiming organic matter by activated sludge.Results indicated that in the early 30 min,absorption process of organic matter by activated sludge was found to be mainly physical adsorption,which could be expressed by the Lagergren single-layer adsorption model.The carbon-enriching sludge had the highest adsorption capacity（COD/SS） which was 60 mg/g but the adsorption rate was lower than that of denitrification sludge.While nitrification sludge had the lowest adsorption rate and higher adsorption capacity compared with denitrification sludge,which was about 35 mg/g.The rates of the fitting index θ0 of carbon-enriching,nitrification and denitrification sludge were 0.284,0.777 and 0.923,respectively,which indicated that the sorbed organic matter on the surface of carbon-enriching sludge was the easiest fraction to be washed away.That is,the combination intensity of carbon-enriching sludge and organic matter was the feeblest,which was convenient for carbon-enriching sludge to release sorbed carbon.Furthermore,by fitting with Langmuir model,concentration of organic matter was found to be the key parameter influencing the adsorption capacity of activated sludge,while the influence of temperature was not obvious.The kinetic law of organic matter absorption by activated sludge was developed,which introduces a way to kinetically analyze the removing mechanism of pollutant by activated sludge and provides theoretical base for the reclaiming of nutriments in wastewater by the absorption of activated sludge.