Influence of design and operational parameters on the pathogens reduction in constructed wetland under the climate change scenario

Abstract

Under the climate change scenario, constructed wetlands (CWs) as an engineered system for treating domestic wastewater will face different challenges. Some of them are: (a) the increase of pathogens concentration in wastewater due to the rise of global temperature; (b) higher precipitation that can cause an increase of pathogens due to runoff; (c) the reuse of treated wastewater related to the water scarcity. These problems can affect the capacity of CWs for removal pathogens. In this context, the objective of this review is to provide an overview of the influence of design and operational parameters on pathogens reduction in CWs. To accomplish with this purpose, the published information (> 30 studies) about the reduction of pathogens and the operational and design parameters in different CWs configurations and were gathered. With this data, statistical analyses were performed considering the most relevant variables which significantly influence the removal of pathogens in CWs. For this, principal component analyses (PCA) were achieved for determining, separately, the correlation of operational parameters with fecal coliform (FC) and total coliform (TC) removal. The results of PCA showed that FC and TC were correlated positively with mass removal rates of chemical oxygen demand (COD) and biological oxygen Demand (BOD5), total suspended solids (TSS) removal and the size of support medium. This study is the first approach that analyzes together the design and operational parameters which influence the pathogen removal in CWs. For this reason, these parameters and the increase on microorganism concentrations due to the climate change have to be considered for the future design of CWs.