The Food-Energy-Water (FEW) Nexus includes the closely interconnected resource systems of food, energy, and water. As the world's population expands to an expected 9 billion by 2050, there will be an urgent demand to balance different resources, such as renewable energy sources, agricultural products, and fresh water, across these three systems to achieve different user goals without putting undue strain on the ecosystems that provide these resources. The Central Valley of California has some of the most productive agricultural lands in the world, but salt accumulation in this farming area has already plagued its crop productivity and threatened its long-term agricultural sustainability due to current agricultural production practices and poor subsurface drainage conditions. Since 1984, there have been combined federal and state efforts to investigate the longstanding irrigation drainage issues in the Valley, but there is still a lack of economically feasible solutions due to the complex environmental and food-energy-water (FEW) nexus issues. However, these coupled issues present an opportunity for technological innovation that can not only solve FEW nexus issues, but also provide an economic boost. One reason for the economic infeasibility of current agricultural drainage water treatment methods is the detachment of the desalination process without considering the food-energy-water (FEW) nexus issues. Therefore, this collaborative project will study the FEW nexus issues in a tractable saltwater greenhouse system (SGS) using irrigation drainage waste water for sustainable food production.
The research goal of this project is to systematically investigate the complex FEW nexus issues in a tractable saltwater greenhouse system (SGS) for an innovative, environment-friendly, and economically feasible system solution to reuse agricultural drainage for sustainable food production in the Central Valley of California. This goal will be achieved through the following six specific research objectives: 1) develop a cost-effective evaporator using agricultural drainage water to cool down the SGS with zero-liquid discharge, recover minerals, and minimize the environmental impact; 2) develop a cost-effective condenser to recover water from both evaporative cooling and crop transpiration; 3) demonstrate efficient solar heating during daytime and radiative cooling during nighttime with a cold water storage tank to enable significant energy reduction in the humidification and dehumidification (HDH) desalination process; 4) develop a SGS through engineering and agricultural co-design and find the optimal operating conditions in terms of temperature and relative humidity for both the HDH process and crops grown in the SGS; 5) test the performance and study the FEW nexus issues in the SGS, including measuring water and energy use efficiency, crop yield and quality; and 6) conduct a cost and performance analysis and demonstrate technical and economic feasibility of the application of the SGS in agricultural drainage treatment for water reuse and food production. These objectives will be achieved through collaboration with an integrated team from three universities and one research center of the United States Department of Agriculture (USDA), including the University of California at Merced, the University of California Santa Cruz, the University of Arizona, and Agriculture Research Service of USDA at Parlier. The success of this project to integrate the drainage water treatment process with the irrigation application process will provide an innovative system solution to solve the longstanding challenge of the agriculture salinity problem resulting from irrigation of field crops with saline water. This solution will slow the reduction of land productivity through the use of saline water irrigation and protect land arability from long-term accumulated salinity. The SGS technology can also be extended to secure sustainable greenhouse food production through the application of seawater and brackish water for crop irrigation.
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.
