CIIMAR-Interdisciplinary Centre of Marine and Environmental Research of the University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, 4450-208, Matosinhos, Portugal; ICBAS - Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal.
CIIMAR-Interdisciplinary Centre of Marine and Environmental Research of the University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, 4450-208, Matosinhos, Portugal; Chemistry and Biochemistry Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre 687, 4169-007, Porto, Portugal.
J Environ Manage. 2023 Jan 15;326(Pt A):116642. doi: 10.1016/j.jenvman.2022.116642. Epub 2022 Nov 7.
Reusing reclaimed wastewater is needed to fight water scarcity, reduce freshwater consumption and conserve water resources, but one must ensure that hazardous substances are fully removed/eliminate before that reuse. The potential of lab-scale constructed wetlands (CWs) for the removal of chemical and biological contaminants from livestock wastewater, while maintaining nutrient levels for fertilization, was assessed, evaluating changes in microbial communities, with particular focus on potential pathogens. CW microcosms with two different substrates (lava rock or light expanded clay aggregate), both planted with Phragmites australis, were tested. After 15 days of treatment, removal rates were higher than 80% for Cd, Cr, Cu, Fe, Pb and Zn, in general with no significant differences between the two different substrates. Organic matter and nutrients were also removed but their levels still allowed the used of the treated wastewater as a fertilizer Removal of bacterial contamination was estimated through enumeration of cultivable bacteria. High removal rates of fecal indicator bacteria were observed, reaching >95% for enterococci and >98% for enterobacteria after 15 days of treatment, decreasing hazardous biological contaminants initially present in the wastewater. In addition, the microbial communities in the initial and treated wastewater, and in the plant roots bed substrate, were characterized by using 16SrRNA gene amplicon sequencing. Microbial communities in the CW systems showed a clear shift comparatively with the initial wastewater showing system adaptation and removal potentialities. This also revealed an important removal of the most represented potential pathogenic genus, Clostridium, which relative abundance decreased from 33% to 1% through the treatment. Overall, CWs showed potential to be efficient in removing chemical and biological contaminants, while maintaining moderated levels of nutrients, allowing the reuse of reclaimed water in agriculture, namely as fertilizer. Current results will contribute for the optimization and use of CWs for a sustainable treatment of liquid wastes, promoting the circular economy.
为了应对水资源短缺，减少淡水消耗和保护水资源，需要重复利用再生水，但必须确保在重复使用之前，有害物质被完全去除/消除。本研究评估了实验室规模的人工湿地（CWs）在去除牲畜废水中的化学和生物污染物的同时，维持养分水平以供施肥的潜力，考察了微生物群落的变化，特别关注了潜在的病原体。本研究使用了两种不同的基质（火山岩或轻质膨胀粘土骨料），并种植了芦苇（Phragmites australis）的 CW 微宇宙进行了测试。经过 15 天的处理，Cd、Cr、Cu、Fe、Pb 和 Zn 的去除率均高于 80%，两种不同基质之间没有显著差异。有机物和养分也被去除，但它们的水平仍允许将处理后的废水用作肥料。通过可培养细菌的计数来估计细菌污染的去除。经过 15 天的处理，粪大肠菌群和肠杆菌的去除率分别达到了>95%和>98%，观察到高的粪便指示菌去除率，降低了废水中最初存在的有害生物污染物。此外，通过 16S rRNA 基因扩增子测序，对初始和处理后的废水以及植物根系床基质中的微生物群落进行了表征。与初始废水相比，CW 系统中的微生物群落发生了明显的变化，表明系统适应和去除潜力。这也揭示了一个重要的去除，即最具代表性的潜在致病属梭菌（Clostridium）的相对丰度从 33%下降到 1%。总的来说，CW 具有去除化学和生物污染物的潜力，同时维持中等水平的养分，允许在农业中重复使用再生水，例如用作肥料。目前的结果将有助于优化和利用 CW 进行可持续的废水处理，促进循环经济。
