Ralph E. Martin Department of Chemical Engineering, University of Arkansas, Fayetteville, AR, USA.
Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR, USA.
Water Environ Res. 2021 Oct;93(10):2149-2168. doi: 10.1002/wer.1588. Epub 2021 Jun 14.
This field case study reports findings on disinfection/ammonia removal from aquaculture wastewater and disinfection of irrigation water carried out at an aquaculture farm and two irrigation locations in Hawaii. We used a flow cell incorporating PtRu/graphite anode and graphite cathode for the disinfection/ammonia removal from aquaculture wastewater, and a flow cell assembled with graphite plates as both anode and cathode for the disinfection of irrigation water. The removal of ammonia followed the indirect oxidation mechanism mediated by free chlorine electro-generated at the PtRu/graphite anode. Ammonia removal rate increased with the increase in NaCl concentration, applied current density, or flow rate. The disinfection of aquaculture wastewater can be readily achieved due to the presence of highly germicidal free chlorine species. The disinfection of irrigation water was realized without the addition of chemicals. The disinfection mechanism was attributed to the formation of free chlorine from the anodic oxidation of chloride ions naturally occurring in the water sources. The disinfection efficiency decreased with increasing organic matter concentration. In addition to the flow cell approach, we also successfully demonstrated the disinfection of irrigation water by adding electrolyzed NaCl solution or purging with a mixture of air and chlorine gas, both of which were generated on-site. PRACTITIONER POINTS: Field case study on disinfection/ammonia removal from aquaculture wastewater and disinfection of irrigation water was carried out in Hawaii. Electrochemical flow cell assembled with PtRu/graphite anode and graphite cathode effectively removes ammonia from aquaculture wastewater. Ammonia removal proceeds via the indirect oxidation mechanism mediated by free chlorine electro-generated at the PtRu/graphite anode. Electrochemical flow cell assembled with commercial graphite electrodes enables fast disinfection of coliform bacteria and E. coli. The primary disinfection mechanism is through chlorine species electro-generated from chloride oxidation at the graphite anode.
本现场案例研究报告了在夏威夷的一个水产养殖场和两个灌溉地点进行的水产养殖废水消毒/氨去除和灌溉水消毒的研究结果。我们使用了一个包含 PtRu/石墨阳极和石墨阴极的流动池来进行水产养殖废水的消毒/氨去除，以及一个由石墨板作为阳极和阴极组装的流动池来进行灌溉水的消毒。氨的去除遵循由 PtRu/石墨阳极上电生成的自由氯介导的间接氧化机制。氨去除率随着 NaCl 浓度、施加电流密度或流速的增加而增加。由于存在高杀菌力的自由氯物种，因此可以很容易地实现水产养殖废水的消毒。灌溉水的消毒无需添加化学物质。消毒机制归因于水中自然存在的氯离子在阳极氧化过程中形成的自由氯。消毒效率随着有机物浓度的增加而降低。除了流动池方法外，我们还成功地通过添加现场产生的电解 NaCl 溶液或用空气和氯气混合物吹扫来实现灌溉水的消毒。
在夏威夷进行了水产养殖废水消毒/氨去除和灌溉水消毒的现场案例研究。
由 PtRu/石墨阳极和石墨阴极组装的电化学流动池有效地从水产养殖废水中去除氨。
氨的去除通过 PtRu/石墨阳极上电生成的自由氯介导的间接氧化机制进行。
由商业石墨电极组装的电化学流动池能够快速消毒大肠菌群和大肠杆菌。
主要消毒机制是通过在石墨阳极上的氯化物氧化产生的氯物种。
