Challenges and opportunities in reuse of treated municipal wastewater for agriculture in the United States: a critical review

In agricultural regions worldwide that are affected by water scarcity, economic activity is often constrained by limited water availability. This paper provides a critical overview of current water-use practices in the agricultural sector, the state of the art in municipal wastewater treatment technologies, and the technical and non-technical challenges associated with advanced treatment and reuse of wastewater effluent for agricultural irrigation in the United States. The reuse of treated municipal wastewater (TMW) in agriculture offers a reliable and locally available water source that can reduce vulnerability to drought and other water supply constraints. It can also deliver significant economic and environmental benefits by lowering energy demand, reducing reliance on river and stream diversions, and decreasing pollutant loads from wastewater discharges. However, effluent from conventional wastewater treatment plants (WWTPs) presents substantial technical and water-quality challenges for agricultural irrigation, primarily due to residual salinity, bacterial and viral pathogens, and contaminants of emerging concern (CECs). Moreover, increasing water scarcity coupled with stricter discharge regulations underscores the need for more comprehensive water-quality characterization of TMW to support its broader adoption while avoiding unintended environmental and public health consequences. Advanced wastewater treatment technologies, combined with improved water-quality monitoring and transparent reporting, are therefore essential to enhancing public confidence and improving marketability of TMW for agricultural reuse.