Effect on plant growth and microbial food safety arising from treated anaerobic effluent irrigation


Project Description

Currently, about 70% of the global freshwater supplies are withdrawn for agricultural irrigation. Food production is water-thirsty and with the projected increase in global human population from the current 7 billion to 9.7 billion in 2050, the amount of water to be channeled into food production is expected to increase in the near future. Intensive mining of non-renewable groundwater supplies for food production is unsustainable. Alternative water resources like treated wastewater should be considered so as to alleviate the demand on groundwater and surface water. One of the barriers towards safe water reuse is the wastewater treatment process. In particular, existing wastewater treatment plants have to be retrofitted with membrane filtration to ensure a substantial removal of emerging contaminants.  However, existing membrane bioreactors are generally aerobic systems which incur high energy costs. In contrast, anMBRs have several advantages. First, anMBRs generate energy that can be harvested to operate the process as a decentralized system. This is significant as most agricultural fields are off the infrastructure grid. Second, anMBRs do not produce a large amount of sludge and hence diminish the need for solid disposal. Third, the membrane separation unit improves effluent quality. Fourth, anMBRs produce effluents that retain the original concentration of nitrogen and phosphorus. This nutrient-rich effluent can be used to irrigate and fertilize the crops. This project therefore hypothesized thatcrop yield obtained from treated anaerobic effluent would be maintained at a comparable rate as that obtained from groundwater or partial desalinated water, without the need to add further N and P fertilizers. It is further hypothesized that the high quality effluent, being collected post membrane filtration, would not detrimentally impact food safety. The proposed project aims to demonstrate the validity of both hypotheses. ​​​​
Program - Environmental Science and Engineering
Division - Biological and Environmental Sciences and Engineering
Center Affiliation - Water Desalination and Reuse Center
Field of Study - ​Applied microbiology; environmental sciences

About the

Peiying Hong

Associate Professor, Environmental Science and Engineering

Peiying Hong
Professor Hong’s research interests include molecular microbiology and microbial aspects in water and wastewater ecosystems. Her research aims to understand the roles and interactions of microorganisms in these ecosystems, and to utilize the insights to solve issues related to water quality and water reuse. Professor Hong’s research also looks at the biotic contaminants (e.g. antibiotic resistance genes, mobile genetic elements, pathogens) that are present in the natural and engineered environments.

Desired Project Deliverables

​Growing of lettuce or tomato plants over a 2 month period to assess impact on leafing, flowering and fruiting process. Characterize microbial community in crops and soils exposed to treated wastewater​