生物淋滤去除农用污泥中重金属的效果及工艺

Removal and process of heavy metals in sludge by microbiological leaching for agricultural use

污水处理厂污泥中的重金属含量高是污泥农用的主要障碍。该文针对天津污水处理厂污泥含铜量高的特性,分别以硫酸亚铁和硫粉作为培养基进行生物淋滤对比试验,前者对铜的去除率远远高于后者。以硫酸亚铁作为培养基,研究了投配比、接种污泥量、pH值和温度对污泥中重金属去除效果的影响。结果表明,在硫酸亚铁投配比为10 g/L、污泥接种量为20%、温度为28℃、淋滤时间为4 d时,污泥中重金属Cu、Pb、Cr、Ni、Zn和Cd的去除率分别为89%、38%、61%、 76%、72%和57%,其相应残余量分别为116、62.5、98、22、174、1.1 mg/kg。在7～28℃范围内,温度越高,氧化亚铁硫杆菌活性越高,生物淋滤时间越短;28℃和35℃下氧化亚铁硫杆菌活性基本相同。以硫酸亚铁为培养基淋滤处理后污泥中重金属的含量可满足《农用污泥中污染物控制标准》(GB4284-1984)。

The high concentration of heavy metals in wastewater sludge has limited the application of the sludge on agricultural land.Under the circumstances of high Cu content in the sludge from wastewater treatment plants in Tianjin City,the microbiological leaching experiments using ferrous sulfate and sulfur powder as the culture respectively,were performed.The results showed that Cu could be removed more efficiently using ferrous sulfate as the culture than that using sulfur powder.Using the ferrous sulfate as th...