曝气强度对城市污泥重金属生物沥滤过程的影响研究

Effect of aeration rate on bioleaching heavy metal from sewage sludge

以氧化亚铁作为底物,氧化亚铁硫杆菌(Thiobacillus.ferrooxidans)为主要沥滤微生物,在底物投配比为10 g/L,温度为25℃,污泥浓度为12.3g/L的条件下,采用5种不同曝气强度对桂林城市污泥中重金属进行生物沥滤试验。结果表明,生物沥滤的经济曝气强度宜控制在每升污泥0.4L/(m in.L),沥滤3 d后,污泥中超标元素Cu、Zn和Cd的去除率分别达到62.53%、67.80%和54.63%,沥滤处理后污泥中残余重金属含量符合污泥农用的国家标准。

In this research,sewage sludge taken from Guilin Wastewater Treatment Plant（WWTP） was selected as cultivation medium for the growth of Thiobacillus ferrooxidans.Ferrous sulfate（FeSO4·7H2O） as energy substrate was added into sludge.Bioleaching systems with five different aeration rates were controlled under the same conditions： substrate dosage 10 g/L,temperature 25℃ and concentrations of sewage 12.3 g/L.The experimental results showed that the aeration rate controlled at 0.4 L/（min·L）was suitable.After three days＇ operation,the removal rates of Cu,Zn and Cd in fresh sludge were 62.53%,67.8% and 54.63% respectively.The residual contents of the three metals in treated sludge also accorded with the national criterion for sludge land use.