污泥中重金属的生物沥滤及其机理分析

为解决污泥农用的主要障碍之一——污泥中重金属含量超标的问题，采用生物法对污泥中的重金属沥滤进行了研究．试验结果表明，在土著硫杆菌的作用下，可使污泥中的Cu、Zn、Cd、Cr、Ni、Pb分别有77．7％、80．3％、54．1％、38．5％、71．6％和26．4％溶出；而硫氧化成硫酸可使污泥中的总大肠菌群大量减少．污泥经生物沥滤后，其重金属含量大大低于污泥农用质量标准．     

Microbial corrosion of concrete

Summary Sulphuric-acid-producing thiobacilli cause severe corrosion of concrete walls in sewage pipelines. The bacteria excrete sulphuric acid, which degrades carbonaceous binding material. Nitrifying organisms have been found in high cell numbers on historical sandstone buildings as well as on concrete buildings. The nitric acid, which is excreted by these organisms as metabolic end-product, also causes severe corrosion. The microorganisms are able to metabolize inorganic substances like ammonia and NO originating from air pollution.The natural process was remodelled by means of simulation experiments. It became evident that mineral-acid-producing bacteria play an important role in biodeterioration of building materials.