School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China.
School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China.
Sci Total Environ. 2021 Aug 20;783:146990. doi: 10.1016/j.scitotenv.2021.146990. Epub 2021 Apr 18.
Nanofiltration (NF) concentrate generated from the secondary wastewater treatment contains high concentration of ammonium nitrogen and refractory organics, thus having great environmental risks. In this study, an electro-oxidation (EO) reactor built up with a boron-doped diamond (BDD) anode is utilized to treat the NF concentrate. To reach "zero liquid discharge", a mixture of the electrolytic effluent and the raw secondary wastewater was collected and transported back to the NF module. Results show that under the current density of 30 mA·cm, most of ammonia nitrogen was decomposed into N-gases within 30 min due to the active chlorine radicals generated in the electrochemical process. Moreover, the EO reactor completely eliminated antibiotics, humic acids and bacteria in the NF concentrate under long electrolysis time of 60 min. In particular, the organic pollutants removal rate was kept at a stable value in the EO reactor for a long-term operation of up to 120 h. In addition, the NF membrane remained a constant permeate flux without being affected by the membrane biofouling caused by organic components in wastewater. Our study highlights the potential of the NF-EO process as a "zero liquid discharge" approach for treatment of the secondary wastewater.
纳滤（NF）浓缩液来自二级废水处理，含有高浓度的氨氮和难降解有机物，因此具有很大的环境风险。在这项研究中，采用带有掺硼金刚石（BDD）阳极的电氧化（EO）反应器来处理 NF 浓缩液。为了达到“零液体排放”，将电解流出物和原始二级废水的混合物收集并送回 NF 模块。结果表明，在 30 mA·cm 的电流密度下，由于电化学过程中产生的活性氯自由基，大部分氨氮在 30 分钟内分解为 N 气体。此外，在 60 分钟的长时间电解下，EO 反应器完全去除了 NF 浓缩液中的抗生素、腐殖酸和细菌。特别是，在长达 120 小时的长期运行中，有机污染物的去除率在 EO 反应器中保持稳定值。此外，NF 膜的透过通量保持不变，不受废水中有机成分引起的膜生物污染的影响。我们的研究强调了 NF-EO 工艺作为处理二级废水的“零液体排放”方法的潜力。
