Faculty of Public Health, Gonabad University of Medical Sciences, Gonabad, Iran.
Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan, Republic of China.
Global Health. 2020 Feb 3;16(1):13. doi: 10.1186/s12992-020-0546-y.
Due to unrestricted entry of wastewater into the environment and the transportation of microbial contaminants to humans and organisms, environmental protection requires the use of appropriate purification systems with high removal efficiency for microbial agents are needed. The purpose of this study was to determine the efficacy of current wastewater treatment systems in removing microbes and their contaminants.
A systematic review was conducted for all articles published in 5 Iranian environmental health journals in 11 years. The data were collected according to the inclusion and exclusion criteria and by searching the relevant keywords in the articles published during the years (2008-2018), with emphasis on the efficacy of wastewater treatment systems in removing microbial agents. Qualitative data were collected using a preferred reporting items for systematic reviews and meta-analyzes (PRISMA) standard checklist. After confirming the quality of the articles, information such as the name of the first author and the year of publication of the research, the type of study, the number of samples, the type of purification, the type of microbial agents and the rate of removal of microbial agents were entered into the checklist. Also the removal rates of the microbial agents mentioned in the studies were compared with united states environmental protection agency (US-EPA) standards.
In this study, 1468 articles retrieved from 118 issues of 5 environmental health journals were reviewed. After reviewing the quality of the articles in accordance with the research objectives, 14 articles were included in the study that were published between 2010 and 2018. In most studies, two main indicators Total coliforms and Fecal coliforms in wastewater were investigated. Removing fungi and viral contamination from wastewater was not found in any of the 14 studies. Different systems (activated sludge, stabilization ponds, wetlands, and low and medium pressure UV disinfection systems were used to remove microbial agents in these studies. Most articles used active sludge systems to remove Total coliforms and Fecal coliforms, which in some cases were not within the US-EPA standard. The removal of Cysts and Parasitic eggs was only reporte from stabilization pond systems (SPS) where removal efficiency was found in accordance with US-EPA standards.
Different types of activated sludge systems have higher efficacy to remove microbial agents and are more effective than other mentioned systems in removing the main indicators of sewage contamination including Total coliforms and Fecal coliforms. However, inappropriate operation, maintenance and inadequate handling of activated sludge can also reduce its efficiency and reduce the removal of microbial agents, which was reported in some studies. Therefore, it is recommended to conduct research on how to improve the operation, maintenance, and proper management of activated sludge systems to transfer knowledge to users of sludge systems and prevent further health issues related to microbial agents.
由于废水不受限制地进入环境以及微生物污染物传播给人类和生物，环境保护需要使用具有高去除效率的适当净化系统来去除微生物。本研究的目的是确定当前废水处理系统去除微生物及其污染物的效果。
对 11 年来在 5 种伊朗环境卫生期刊上发表的所有文章进行了系统评价。根据纳入和排除标准，按照文章发表年份（2008-2018 年）检索相关关键词，收集数据，重点关注废水处理系统去除微生物制剂的效果。使用系统评价和荟萃分析的首选报告项目（PRISMA）标准清单收集定性数据。在确认文章质量后，将第一作者姓名和研究发表年份、研究类型、样本数量、净化类型、微生物制剂类型以及微生物制剂去除率等信息输入清单。还将研究中提到的微生物制剂的去除率与美国环境保护署（US-EPA）标准进行了比较。
本研究从 5 种环境卫生期刊的 118 期中检索出 1468 篇文章，对其进行了综述。根据研究目标对文章质量进行审查后，纳入了 14 篇 2010 年至 2018 年发表的文章。在大多数研究中，主要调查了废水中的总大肠菌群和粪大肠菌群。在这 14 项研究中，没有发现从废水中去除真菌和病毒污染的情况。不同的系统（活性污泥、稳定塘、湿地和低、中压紫外线消毒系统）用于去除这些研究中的微生物制剂。大多数文章使用活性污泥系统去除总大肠菌群和粪大肠菌群，在某些情况下，不符合美国环保署的标准。囊和寄生虫卵的去除仅从稳定塘系统（SPS）报告，在该系统中发现去除效率符合美国环保署的标准。
不同类型的活性污泥系统对去除微生物制剂具有更高的功效，在去除总大肠菌群和粪大肠菌群等污水污染的主要指标方面比其他提到的系统更有效。然而，活性污泥系统的不当操作、维护和处理不当也会降低其效率，降低微生物制剂的去除率，一些研究报告了这一点。因此，建议开展研究，探讨如何改进活性污泥系统的操作、维护和适当管理，将知识传递给污泥系统的使用者，防止与微生物制剂有关的进一步健康问题。
