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

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

Internship 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Currently, about 70% of the global freshwater supplies are withdrawn for agricultural irrigation.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 that crop 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. 


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 

Faculty Name

Peiying Hong

Field of Study

Applied microbiology; environmental sciences