Sec. Microbiologia, Virologia i Biotecnologia, Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 643, 08028 Barcelona, Spain.
Sec. Microbiologia, Virologia i Biotecnologia, Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 643, 08028 Barcelona, Spain; Laboratori de Protistologia, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 643, 08028 Barcelona, Spain.
Water Res. 2017 Dec 1;126:450-459. doi: 10.1016/j.watres.2017.09.056. Epub 2017 Sep 29.
This work aims at comparing the ability of two kinds of electrochemical technologies, namely electrocoagulation (EC) and electro-Fenton (EF), to disinfect primary and secondary effluents from municipal wastewater treatment plants. Heterotrophic bacteria, Escherichia coli, enterococci, Clostridium perfringens spores, somatic coliphages and eukaryotes (amoebae, flagellates, ciliates and metazoa) were tested as indicator microorganisms. EC with an Fe/Fe cell at 200 A m and natural pH allowed >5 log unit removal of E. coli and final concentration below 1 bacteria mL of coliphages and eukaryotes from both effluents in ca. 60 min, whereas heterotrophic bacteria, enterococci and spores were more resistant. A larger removal was obtained for the primary effluent, probably because the flocs remove higher amount of total organic carbon (TOC), entrapping more easily the microbiota. EF with a boron-doped diamond (BDD) anode and an air-diffusion cathode that produces HO on site was first performed at pH 3.0, with large or even total inactivation of microorganisms within 30 min. A more effective microorganism removal was attained as compared to EC thanks to OH formed from Fenton's reaction. A quicker disinfection was observed for the secondary effluent owing to its lower TOC content, allowing the attack of greater quantities of electrogenerated oxidants on microorganisms. Wastewater disinfection by EF was also feasible at natural pH (∼7), showing similar abatement of active microorganisms as a result of the synergistic action of generated oxidants like active chlorine and coagulation with iron hydroxides. A sequential EC/EF treatment (30 min each) was more effective for a combined decontamination and disinfection of urban wastewater.
本工作旨在比较两种电化学技术，即电絮凝（EC）和电芬顿（EF），对城市污水处理厂的一级和二级出水进行消毒的能力。异养菌、大肠杆菌、肠球菌、产气荚膜梭菌孢子、粪大肠菌群和真核生物（变形虫、鞭毛虫、纤毛虫和后生动物）被用作指示微生物。在 200 A m 和自然 pH 条件下，采用 Fe/Fe 电池的 EC 可使两种废水的大肠杆菌去除率超过 5 个对数单位，最终浓度低于 1 个细菌 mL 的噬菌体和真核生物，大约 60 min 即可完成，而异养菌、肠球菌和孢子的抵抗力更强。初级出水中的去除率更高，可能是因为絮体去除了更多的总有机碳（TOC），更容易捕获微生物群。采用硼掺杂金刚石（BDD）阳极和空气扩散阴极的 EF 首先在 pH 3.0 下进行，30 min 内微生物几乎全部失活。与 EC 相比，EF 由于芬顿反应产生的 OH，可实现更有效的微生物去除。由于二级出水中的 TOC 含量较低，消毒速度更快，可允许更多数量的电生成氧化剂攻击微生物。EF 对废水的消毒在自然 pH（约 7）下也是可行的，由于生成的氧化剂（如活性氯和铁氢氧化物的混凝）的协同作用，活性微生物的去除率相似。顺序进行的 EC/EF 处理（各 30 min）对于城市废水的联合去污和消毒更为有效。
