Abstract:

Hydrogen peroxide (H₂O₂), as a green oxidant, is widely used in pharmaceuticals, textile, chemical synthesis and other enterprises. The wastewater produced from these enterprises enters the sewage biological treatment system, which affects biological activity and the efficiency of sewage treatment. In the study, the effect of H₂O₂ on the removal efficiencies of pollutants and catalase activity in the SBR were investigated. The changes of extracellular polymers (EPS) compositions and sludge properties were analyzed, and the decomposition pathway of H₂O₂ and its influence mechanisms on the activated sludge were explored. The results showed that ·OH and ·O{}_{\mathrm{2}}^{-} produced by low concentration of H₂O₂ (<90 mg/L) decomposition had a synergistic effect, and removal efficiencies of COD and TN were improved. The sludge surface became rougher, the flocculation particles were larger and sludge flocculation was improved. The contribution of ·OH was higher than that of ·O{}_{\mathrm{2}}^{-}. However, high concentration of H₂O₂ (>90 mg/L) inhibited the removal of TN, and catalase activity, sludge flocculation and EPS concentration all reduced. When the concentration of H₂O₂ is 90 mg/L, the removal rate of COD and TN is the highest, and the enzyme activity is the highest. Therefore, the purpose of improving the removal rate of pollutants and sludge flocculation can be achieved by adjusting the concentration of H₂O₂.

Key words: wastewater, H₂O₂, bioreactors, enzyme, sludge properties, radical

摘要：

双氧水（H₂O₂）作为氧化剂，被广泛用于制药、纺织、化学品合成等企业，这些企业产生的废水进入污水生物处理系统，影响微生物活性和污水处理效果。考察H₂O₂对污染物去除率和过氧化氢酶活性的影响，分析胞外聚合物组成和污泥性质的变化，探索H₂O₂在污泥系统中的分解途径及其对污泥的作用机理。结果表明：低浓度H₂O₂（<90 mg/L）分解产生的·OH和·{\mathrm{O}}_{\mathrm{2}}^{-}具有协同作用，提高了COD和TN去除率，污泥表面变粗糙，絮凝颗粒增大，促进污泥絮凝，其中·OH贡献度大于·{\mathrm{O}}_{\mathrm{2}}^{-}。高浓度H₂O₂（>90 mg/L）对TN的去除产生抑制作用，酶活性、污泥絮凝性和胞外聚合物浓度降低。当H₂O₂浓度为90 mg/L时，COD和TN去除率最高，酶活性最高，因此，通过调控H₂O₂浓度可实现提高污染物去除率和污泥絮凝性的目的。

关键词: 废水, H₂O₂, 生物反应器, 酶, 污泥性质, 自由基