ABSTRACT

Removal of micropollutants in wastewaters has gained importance in recent years. Advanced treatment processes such as ozone oxidation, activated carbon adsorption, and membrane filtration are required to remove the micropollutants from wastewaters. In this study, extended ozonation was applied at different stages of a wastewater treatment plant (WWTP) to determine its effect on the removal efficiencies of both macro and micropollutants. At the first experimental study, wastewater that was obtained from the effluent of the aerated grit chamber of a conventional full-scale municipal WWTP, was treated with a concentration of 30 mg/L FeCl₃ through a laboratory scale jar test system followed by a laboratory-scale ozonation unit. According to the results, chemically enhanced primary treatment (CEPT) achieved removal efficiencies over 75% for chemical oxygen demand (COD), 50% for total phosphorus (TP) and 90% for total-suspended solids (TSS), while ozonation followed by the CEPT resulted with an overall COD removal efficiency up to 93%. As a second experimental study, effluent of the overloaded conventional activated sludge (CAS) system of the same WWTP was solely post ozonated. 90 min of post-ozonation resulted with a decrease by 70% and an increase by 50% in ammonium and nitrate concentration, respectively. Over 99% removal efficiency of diclofenac was achieved in each experimental study (CEPT+O₃ and CAS+O₃). Results of each experimental study were evaluated in terms of both efficiency and feasibility. Since the ozonation results with an increase in the concentration of oxidized nitrogen; applying ozonation to a preliminary-treated wastewater after CEPT can be advantageous in some cases, where nitrate can be used as electron acceptor in anoxic environments for deep-sea discharges.

摘要

近年来，去除废水中的微污染物变得越来越重要。需要采用臭氧氧化、活性炭吸附、膜过滤等深度处理工艺去除废水中的微污染物。在这项研究中，扩展臭氧作用应用于污水处理厂 (WWTP) 的不同阶段，以确定其对宏观和微量污染物去除效率的影响。在第一次实验研究中，从传统全规模市政污水处理厂曝气沉砂池的出水中获得的废水，用浓度为 30 mg/L 的 FeCl _{3 进行处理}通过实验室规模的广口瓶测试系统，然后是实验室规模的臭氧化装置。根据结果​​，化学增强初级处理 (CEPT) 的化学需氧量 (COD) 去除率超过 75%，总磷 (TP) 去除率超过 50%，总悬浮固体 (TSS) 去除率达 90%，而臭氧化后去除CEPT 的整体 COD 去除效率高达 93%。作为第二项实验研究，同一污水处理厂的超负荷常规活性污泥 (CAS) 系统的出水仅经过臭氧化处理。后臭氧化 90 分钟导致铵和硝酸盐浓度分别降低 70% 和增加 50%。在每项实验研究（CEPT+O ₃和 CAS+O ₃）。每个实验研究的结果都在效率和可行性方面进行了评估。由于臭氧化导致氧化氮浓度增加；在某些情况下，在 CEPT 后对预处理过的废水应用臭氧处理可能是有利的，其中硝酸盐可用作深海排放缺氧环境中的电子受体。