Abstract:

Using reactive brilliant (RB) blue as anthraquinones model pollutants, the inhibition mechanism on methanogenic activity of anaerobic granular sludge was investigated. Likewise, the effect of sludge characteristics on particle size distribution (PSD), metal content and extracellular polymeric substances (EPS) via pre-treatment of heterogeneous Fenton-like oxidation were evaluated. Lastly, degradation pathway of RB blue was proposed. The results showed that RB blue had metabolic or even physiologic toxicity for methanogens. When RB blue was injected into anaerobic reactor, COD removal efficiency was reduced and partical size of anaerobic granular sludge was decreased. Meanwhile, the calcium and magnesium ion concentrations of the granular sludge decreased from 40.5 and 16.2 mg·L^-1 to 22.5 and 6.8 mg·L^-1, respectively. The stability and flocculability of the granular sludge were deteriorated. However, by pre-treatment of heterogeneous Fenton-like oxidation, COD removal efficiency climbed to more than 90%, while the contents of EPS, protein and polysaccharide increased to 98.7, 69.9, and 28.8 mg·(g VSS)^-1, respectively, which guaranteed the favorable stability and activity of the anaerobic granular sludge. The exploration on degradation pathway of RB blue indicated that the hydroxyl free radicals firstly attacked triazine group and anthraquinone structure of RB blue, producing phthalic acid and benzoic acid. After that, they were degraded into small molecule carboxylic acid such as butyric acid, oxalic acid, acetic acid, and so on. The toxicity was reduced, which was beneficial to the anaerobic biological post-treatment.

Key words: reactive brilliant blue, heterogeneous Fenton-like, toxicity assessment, anaerobic, catalyst, particle size distribution

摘要：

以蒽醌类染料活性艳蓝为目标污染物,探讨了其对产甲烷菌的抑制机理;分析了其经多相类芬顿预处理前后对厌氧污泥EPS、粒径分布、金属离子含量的影响;同时对活性艳蓝的降解途径进行了探究。结果表明,活性艳蓝对产甲烷菌具有代谢毒性甚至生理性毒性;其进入厌氧反应器后,会造成COD去除率降低;颗粒污泥粒径减少,污泥中钙、镁离子浓度分别由40.5和16.2 mg·L^-1降低到22.5和6.8 mg·L^-1,污泥的稳定性与絮凝性变差。而经多相类芬顿预处理后,COD去除率可达90%以上,厌氧颗粒污泥EPS总量、蛋白质含量、多糖含量分别增大到98.7、69.9和28.8 mg·(g VSS)^-1,为保持颗粒污泥的活性与稳定性提供了保障。多相类芬顿体系所产生的羟基自由基首先攻击活性艳蓝的三嗪基团及不饱和共轭键的蒽醌结构,继而生成邻苯二甲酸、苯甲酸,再被降解为丁酸、草酸、乙酸等小分子羧酸,从而降低了其毒性,有利于后续厌氧生物处理的进行。

关键词: 活性艳蓝, 多相类芬顿, 毒性评价, 厌氧, 催化剂, 粒径分布