PIRE: Climate Resilient Sustainable Food Production: Controlled Environment Hydroponic Agriculture with Novel Wastewater Treatment & Reuse

Increasingly frequent regional droughts induced by climate change have raised concerns about food security. Given the high land, water, energy, and carbon footprints of traditional open field crop cultivation, controlled environment agriculture using greenhouses or modular containers is becoming more advantageous. In regions with freshwater scarcity, non-traditional water sources such as reclaimed wastewater are being considered for irrigation.

However, there are concerns about the unit costs and energy requirements of wastewater treatment as well as potential microbial risks to consumers. Here, the team advances the development of a sustainable agriculture platform where irrigation water contains plant nutrients present in wastewater. An anaerobic membrane bioreactor (AnMBR) is used to treat wastewater and produce methane-rich biogas.

Recovered methane offset the energy requirements of the system. It can be converted to carbon dioxide to enrich the atmosphere around the plants to enhance their growth. The AnMBR uses its inherent membrane and an ultraviolet disinfection step to remove pathogens from the water.

Plants such as lettuce are grown with a hydroponic (soil-less) nutrient film technique that is engineered to efficiently use the water and nutrients from the AnMBR. This is a way to simultaneously reduce water and fertilizer consumption. Recycling the water from the nutrient film technique allows maximizing the "crop per drop." This project also supports one postdoctoral fellow, and graduate and undergraduate students notably from underrepresented groups in science.

Its outcomes may provide a climate-smart solution yielding fresh vegetables in densely populated areas.

This project is a collaboration between investigators in the United States at Clemson University and in the Republic of Korea at Gyeongsang National University and Korea University. Korea is a global leader in controlled environment agriculture (CEA). The international collaboration allows a comparative assessment of different crops, climate conditions, and cultural perspectives.

It enables concept exchange between the two distinct global regions. A contrast of CEA activities in the USA and Korea facilitates knowledge transfer about best practices in peri-urban and urban agriculture. The project has five thrusts: (1) development and testing of the AnMBR system; (2) development and testing of the nutrient film technique (NFT) system; (3) integrating sensors for monitoring nutrients and waterborne pathogens into and out of the systems; (4) studying good manufacturing practices, microbial risk, and food safety; (5) performing a technoeconomic analysis and life cycle assessment.

Educational integration will be realized through three unique components: (1) a virtual and physical exchange program between PhD students of all participating institutions; (2) a tiered, multi-institutional research and mentoring program incorporating undergraduate students; (3) a "hack-a-thon" event comprised of interdisciplinary student teams blended across institutions. The investigators will exchange knowledge with growers, government representatives, and consumers through the activities of a Stakeholder Advisory Group.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.