A number of 2-substituted benzothiazoles that are known to be used as fungicides, corrosion inhibitors and vulcanization accelerators in industry have been analyzed in municipal wastewater and the effluents of activated sludge and membrane bioreactor (MBR) treatment over a three month period. All six analytes were regularly detected in the municipal wastewater by liquid chromatography-mass spectrometry and amount to a total concentration of 3.4 μg/L. Of these compounds benzothiazole-2-sulfonic acid (1,700 ng/L), benzothiazole (850 ng/L) and 2-hydroxybenzothiazole (500 ng/L) were most prominent. The source of the benzothiazole emission is yet unknown. Activated sludge treatment did not reduce total benzothiazole concentration significantly. Removals of the individual compounds ranged from 90% for 2-mercaptobenzothiazole and 70% for hydroxybenzothiazole to 40% for benzothiazole. The concentration of benzothiazole-2-sulfonic acid increased by 20%, whereas 2-methylthiobenzothiazole increased by 160% during activated sludge treatment, likely due to the methylation of mercaptobenzothiazole. Total benzothiazole removal in two parallely operated MBRs was significantly better (43%) than in the conventional activated sludge treatment. Namely benzothiazole and benzothiazole-2-sulfonic acid were more effectively removed. This first systematic study on the occurrence of benzothiazoles in municipal wastewater has shown that this is a relevant class of trace contaminants in municipal wastewater which is only incompletely removed in biological wastewater treatment. Emission from sewage treatment is dominated by the most polar benzothiazole-2-sulfonic acid. MBR treatment may reduce but cannot avoid this emission.

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城市废水中苯并噻唑的存在及其在生物处理中的归宿

在三个月的时间内，对城市废水以及活性污泥和膜生物反应器 (MBR) 处理的废水中的多种已知在工业中用作杀菌剂、腐蚀抑制剂和硫化促进剂的 2-取代苯并噻唑进行了分析。通过液相色谱-质谱法定期在城市废水中检测到所有六种分析物，总浓度为 3.4 μg/L。在这些化合物中，苯并噻唑-2-磺酸（1,700 ng/L）、苯并噻唑（850 ng/L）和2-羟基苯并噻唑（500 ng/L）最为突出。苯并噻唑排放的来源尚不清楚。活性污泥处理没有显着降低总苯并噻唑浓度。各个化合物的去除率从 2-巯基苯并噻唑 90% 和羟基苯并噻唑 70% 到苯并噻唑 40% 不等。在活性污泥处理过程中，苯并噻唑-2-磺酸的浓度增加了20%，而2-甲硫基苯并噻唑的浓度增加了160%，这可能是由于巯基苯并噻唑的甲基化所致。两个并联运行的 MBR 中苯并噻唑的总去除率明显优于传统活性污泥处理（43%）。即苯并噻唑和苯并噻唑-2-磺酸被更有效地去除。这项关于城市废水中苯并噻唑存在的首次系统研究表明，这是城市废水中一类相关的微量污染物，在生物废水处理中只能不完全去除。污水处理的排放主要是极性最强的苯并噻唑-2-磺酸。MBR 处理可能会减少但无法避免这种排放。