Background : Conventional septic tank (ST) systems are an important and relatively low-cost type of decentralized on-site sanitation infrastructure. Although ST systems are one of the most applied decentralized sanitation technologies globally, limited research has been performed to identify the type and degree of biodegradation mechanisms present within the tanks themselves; which are assumed to occur but have not yet been adequately characterized. Objectives: To assess available literature for evidence supporting the presence and relationship between anaerobic conditions, microbiology and activity by reviewing the current literature on the conventional ST in order to characterize the assumed anaerobic biodegradation mechanisms therein. Methods: A systematic review and meta-analysis was performed in two databases (Web of Science & Google Scholar) along with supplemental literature reporting linkages between STs and the anaerobic characterization of ST sludge. 112 records were found, of which 30 studies were retained that met the review's inclusion criteria. Results: Few studies included data on the conventional ST. Of those that did, data suggests that anaerobic conditions are present. The lack of quality and quantity in the results pertaining to anaerobic microbiology and activity raised concerns regarding the comparability and reliability of these results to accurately characterize biodegradation mechanisms. Conclusions: This review's findings support the assumption that anaerobic conditions are present in a conventional ST; however, due to the lack of robust data regarding anaerobic microbial communities and activity, it cannot be concluded that a ST is treating waste with anaerobic biodegradation processes. These findings highlight the need to further investigate the strength and effects of this relationship, especially in the context of reaching global improved- and sustainable-sanitation targets.

中文翻译：

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传统化粪池的生物降解机理和功能微生物学：系统评价和荟萃分析

背景 ：传统的化粪池（ST）系统是一种重要的且成本相对较低的分散式现场卫生基础设施。尽管ST系统是全球应用最广泛的分散式卫生技术之一，但为确定储罐本身中存在的生物降解机制的类型和程度，已经进行了有限的研究。假定发生了但尚未充分表征。目的：通过回顾有关常规ST的最新文献来表征其中假定的厌氧生物降解机制，以评估可利用的文献，以支持厌氧条件，微生物学和活性之间的关系。方法：在两个数据库（Web of Science和Google Scholar）中进行了系统的综述和荟萃分析，以及补充文献报道了ST与污泥的厌氧特性之间的联系。找到112条记录，其中30项研究符合审查的纳入标准。结果：很少有研究包括常规ST的数据。在那些情况下，数据表明存在厌氧条件。与厌氧微生物学和活性有关的结果缺乏质和量，引起了人们对这些结果的可比性和可靠性的关注，以准确表征生物降解机制。结论：本评价的发现支持了常规ST中存在厌氧条件的假设；但是，由于缺乏有关厌氧微生物群落和活性的可靠数据，因此不能得出结论：ST正在采用厌氧生物降解工艺处理废物。这些发现强调了需要进一步研究这种关系的强度和影响，特别是在实现全球改善和可持续卫生目标的背景下。