Monitoring Opportunistic Pathogens in Domestic Wastewater from a Pilot-Scale Anaerobic Biofilm Reactor to Reuse in Agricultural Irrigation

• Main Authors: Bingjian Cui, Shengxian Liang
• Format: Article
• Language: English
• Published: MDPI AG 2019-06-01
• Series: Water
• Subjects: domestic wastewater; bacterial pathogens; qPCR; agricultural reuse
• Online Access: https://www.mdpi.com/2073-4441/11/6/1283

Wastewater reuse for agricultural irrigation in many developing countries is an increasingly common practice. Regular monitoring of indicators can help to identify potential health risks; therefore, there is an urgent need to understand the presence and abundance of opportunistic pathogens in wastewater, as well as plant phyllosphere and rhizosphere. In this study, an anaerobic biofilm reactor (ABR) was developed to treat rural domestic wastewater; the performance of pollutants removal and pathogenic bacteria elimination were investigated. Additionally, we also assessed the physicochemical and microbiological profiles of soil and lettuces after wastewater irrigation. <i>Aeromonas</i> <i>hydrophila</i>, <i>Arcobacter</i> sp., <i>Bacillus cereus</i>, <i>Bacteroides</i> sp., <i>Escherichia coli</i>, <i>Legionella</i> sp., and <i>Mycobacterium</i> sp. were monitored in the irrigation water, as well as in the phyllosphere and rhizosphere of lettuces. Pathogens like <i>B</i>. <i>cereus</i>, <i>Legionella</i> sp. and <i>Mycobacterium</i> sp. were present in treated effluent with relatively high concentrations, and the levels of <i>A</i>. <i>hydrophila</i>, <i>Arcobacter</i> sp., and <i>E. coli</i> were higher in the phyllosphere. The physicochemical properties of soil and lettuce did not vary significantly. These data indicated that treated wastewater irrigation across a short time period may not alter the soil and crop properties, while the pathogens present in the wastewater may transfer to soil and plant, posing risks to human health.