SBR活性污泥系统去除模拟废水中Pb^(2+)的研究

Study on Pb^(2+)Removal from Simulated Wastewater by Activated Sludge in Sequencing Batch Reactor

为了考察不同Pb^(2+)浓度(3、5、10 mg/L)下,SBR活性污泥系统对模拟含铅废水中Pb^(2+)的去除效果,分析了活性污泥去除Pb^(2+)的影响因素,并采用动力学模型、红外光谱及X射线能谱对活性污泥吸附Pb^(2+)的机理进行了研究.结果表明:①Pb^(2+)浓度分别为3和5 mg/L时,SBR活性污泥系统对模拟含铅废水中Pb^(2+)的去除率均在98%以上,该系统中活性污泥的Pb^(2+)吸附量为6.2 mg/g;Pb^(2+)浓度为10 mg/L时,SBR活性污泥系统运行后期Pb^(2+)的去除率有所下降,这与该系统Pb^(2+)累积量(351.6 mg)过高有关.②在Pb^(2+)长期作用下,SBR活性污泥系统各试验阶段的MLSS均会经历先下降再恢复的过程,且该系统中生物多样性和物种丰富度明显下降,可逐渐筛选出对Pb^(2+)耐受性较强的微生物.③SBR活性污泥系统去除Pb^(2+)的适宜pH范围为6~7,最佳温度为25℃.④活性污泥对Pb^(2+)的吸附机理主要表现为化学吸附作用,包含表面有机络合、离子交换等过程.研究显示,SBR活性污泥系统更适用于处理低浓度(3、5 mg/L)的含Pb^(2+)废水.

In order to explore the removal effect from simulated wastewater with different concentrations of Pb^(2+)(3,5,and 10 mg/L)in the SBR activated sludge system,analyzed influencing factors of Pb^(2+)adsorption effects,and investigated the adsorption mechanism of Pb^(2+)by kinetic model,FTIR and EDS.The results showed that:(1)The removal of Pb^(2+)in the two SBR-activated sludge systems(Pb^(2+)concentration:3 and 5 mg/L)could stably reach more 98%,and Pb^(2+)adsorption capacity was 6.2 mg/g.However,the Pb^(2+)removal rate decreased at later operation stage in the SBR activated sludge system with a Pb^(2+)concentration of 10 mg/L,where 351.6 mg Pb^(2+)was accumulated,suggesting that high cumulation of Pb^(2+)inhibited microbial activity.(2)During the long-term operation,activated sludge concentration(MLSS)decreased first and then recovered in the SBR activated sludge systems with different Pb^(2+)concentrations.Microbial diversity in the Pb^(2+)containing SBR activated sludge system reduced obviously,and Pb^(2+)-resistant microorganisms were screened out.(3)The optimal pH and temperature were 6-7 and 25℃,respectively.(4)The adsorption mechanism of Pb^(2+)by activated sludge was mainly chemical adsorption,such as surface organic complexation and ion exchange.The study showed the SBR activated sludge system is more suitable for treating wastewater with low concentration(3 and 5 mg/L)of Pb^(2+).