Growing food through controlled environment agriculture (CEA) is of great interest for locations like peri-urban areas where soil-based farming is impractical. Hydroponic methods like the nutrient film technique (NFT) are often used. Access to municipal wastewater presents an opportunity to supply hydroponic water with nutrients (nitrogen and phosphorus) already present. If the wastewater is treated anaerobically, organic matter can be converted to biogas, which can then be used to heat the system and supply extra carbon dioxide to the plants, increasing their growth rates. This concept is being studied in a bi-national exchange where investigators from Clemson University, Gyeongsang National University, and Korea University are testing an anaerobic membrane bioreactor (AnMBR) for wastewater treatment and using the effluent to grow lettuce via NFT CEA.

Sea level rise and global warming exacerbate the salinization of surface freshwater and groundwater. Proper water treatment (partial desalination) and salt-tolerant crops are two key components in utilizing abundant marginal-quality water sources and addressing freshwater scarcity in the agricultural sector. In an interdisciplinary USDA funded project we are evaluating nanofiltration and electrodialysis through laboratory experiments and modeling to determine their effectiveness and cost for partial desalination. Naturally occurring saline water has a consistent composition and contains ions that benefit crops (e.g., Ca2+ and Mg2+). Partial desalination technology has the capability to selectively retain beneficial ions and produce tailored waters for salt-tolerant crops. The evolution criteria for proper water treatment include specific energy consumption (SEC), water quantity, and water quality (ion composition).

This presentation will share our laboratory and modeling results for these two projects that explore non-traditional water sources for growing food crops.