污水处理外文翻译---絮凝：污泥性质和废水处理的影响-环境工程(编辑修改稿)

污水处理外文翻译---絮凝：污泥性质和废水处理的影响-环境工程(编辑修改稿)内容摘要：

rised of microbial consortiums and organic and inorganic particles held together in a matrix formed by exocellular polymers and divalent cations (Tezuka, 1969。 Novak and Haugan, 1981。 Eriksson and Alm, 1991。 Bruus et al., 1992。 Higgins and Novak, 1997a, b). Bruus et al. (1992) and Higgins and Novak (1997b) have shown that excess monovalent cations can cause a deterioration in floc structure and settling properties. Improvements in settling properties were observed with an increase in divalent cations. Many industrial systems require influent water of high purity. Therefore, the addition of chemicals during the industrial process and wastewater pretreatment dictate the cationic position of the wastewater entering the activated sludge basins. Often these wastewaters will be deficient in some cations and will contain an overabundance of others. An increase in monovalent ions has been observed to cause a deterioration in dewatering properties in activated sludge, whereas an increase in divalent ions has been shown to improve activated sludge dewatering properties (Higgins and Novak, 1997a, b). These observations were made for activated sludge flocs in laboratory and industrial systems. Higgins and Novak (1997b) evaluated the cations from seven industrial facilities and found that, when the monovalent to divalent cation ratio (M/D) on a chargeequivalent basis exceeded 2, deterioration in dewatering properties (specific resistance to filtration) occurred. The problems associated with a high M/D ratio were most often found in the industries that added caustic for pH control. Therefore, sodium ions were the prevalent monovalent ion input in these systems. The purpose of this study was to evaluate the potential for identification of nonfilamentous settling and dewatering problems through screening of cations, to arrive at a strategy for laboratory or field trials, and to identify and address the associated problem(s). The industrial system studied contained a high concentration of sodium ions(average of 2,000 mg/l) added as sodium hydroxide in the pretreatment step to prevent volatilization of acetic acid. The major ponent in the waste stream was acetic acid. The influent COD was in the order of 10,000 mg/l. The activated sludge had a p。