Implication of environmental factors on the occurrence of pathogens in urban landscape ponds with reclaimed wastewater replenishment

Abstract

Abstract One year of continuous observation of bacterial and viral pathogen concentrations in overlying water and sediment of three urban landscape ponds replenished with reclaimed wastewater (RW) ponds was carried out to establish the distribution of pathogens and investigate the effects of environmental factors on that in RW ponds. The pathogens were represented by Escherichia coli and three common viral pathogens (enterovirus, norovirus, and rotavirus). Results indicated that the peak concentrations of pathogens occur from August to October. Pathogens present in sediment should be paid much more attention than those in overlying water, as they mainly contribute to the favorable conditions for survival and regrowth of pathogens in sediments. Cluster and redundancy analyses revealed that the environmental factors of chlorophyll a (Chl-a), organic matter, and water transparency have key impacts on the occurrence of pathogens. This infers that the practical way to reduce pathogenic risks in RW ponds is to control the algae bloom and improve the transparency of water bodies. Furthermore, based on breakpoint regression analyses, the appropriate ranges of Chl-a and transparency are suggested to be less than 57 mg/m3 and greater than 68 cm, respectively, to reduce the concentration of pathogens in urban landscape ponds replenished with RW.