Department of Civil and Environmental Engineering, University of Missouri, E2509 Lafferre Hall, Columbia, MO 65211, USA.
Water Res. 2013 May 1;47(7):2307-14. doi: 10.1016/j.watres.2013.01.048. Epub 2013 Feb 8.
Melamine is a nitrogen-rich (67% nitrogen by mass) heterocyclic aromatic compound that could significantly increase effluent total nitrogen concentrations. In this study, we investigated the degradation of melamine and its impact on activated sludge operations by employing two common activated sludge processes, namely the Modified Ludzack-Ettinger (MLE) process and the continuous stirred tank reactor (CSTR) process. Melamine was dosed continuously from day 125 in both activated sludge treatment systems at an influent concentration of 3 mg/L for about 100 days. Even after such a long period of sludge adaptation, melamine appeared not to be easily biodegradable. The average melamine removal efficiencies in the CSTR and MLE systems were 14 ± 10% and 20 ± 15%, respectively. There was no significant difference in melamine removal between the two different activated sludge processes. The long-term input of melamine resulted in a decrease in the nitrifying bacterial activities (by 82 ± 8%) and population in both systems. Short-term microtiter assay results also showed that melamine reduced activated sludge growth by 80% when supplied at a concentration of 75.6 mg/L. These results suggest that sludge adaptation plays a minimal role in melamine degradation, as the enzymes responsible for hydrolytic deamination of melamine in activated sludge are not easily induced. The insignificant biodegradation of melamine is also attributed to bacterial growth inhibition under long-term dosing conditions with melamine, resulting in a significant decrease in effluent water quality.
三聚氰胺是一种富氮（质量分数 67%为氮）杂环芳香族化合物，可显著提高出水总氮浓度。本研究采用两种常见的活性污泥工艺，即改良 Ludzack-Ettinger（MLE）工艺和连续搅拌槽式反应器（CSTR）工艺，研究了三聚氰胺的降解及其对活性污泥运行的影响。在这两种活性污泥处理系统中，从第 125 天开始连续投加三聚氰胺，进水浓度为 3mg/L，持续约 100 天。即使经过这么长时间的污泥驯化，三聚氰胺似乎也不易生物降解。CSTR 和 MLE 系统中三聚氰胺的平均去除率分别为 14±10%和 20±15%。两种不同的活性污泥工艺对三聚氰胺的去除率没有显著差异。长期输入三聚氰胺导致两种系统中的硝化细菌活性（下降 82±8%）和数量减少。短期微量滴定试验结果还表明，当以 75.6mg/L 的浓度供应时，三聚氰胺会使活性污泥的生长减少 80%。这些结果表明，污泥驯化在三聚氰胺降解中作用不大，因为活性污泥中负责水解脱氨的酶不易诱导。在长期投加三聚氰胺的条件下，由于细菌生长受到抑制，导致出水水质显著下降，也是三聚氰胺生物降解不明显的原因之一。
