BY ERIN COGSWELL

A team of interdisciplinary researchers in the UNT Advanced Environmental Research Institute (AERI) and College of Engineering is exploring how the desalination of brackish water could make food production more sustainable. 

The three-year project is examining how brackish groundwater desalination costs could be offset by using its byproducts — desalination concentrate or brine — for profitable food production. For this study, the team will work with producing shrimps, specifically the freshwater prawn Macrobrachium rosenbergii. The research is backed by a $1 million grant from a joint funding program of the National Science Foundation and U.S. Department of Agriculture.

The work combines the expertise of co-PIs Miguel Acevedo, Regents Professor of Electrical Engineering, Edward Mager, an assistant professor in the Department of Biological Sciences, and Xinrong Li, associate professor and interim chair of the Department of Electrical Engineering, along with the research coordinator Breana Smithers.

The team will develop a testbed of integrated sensors, controls, machine learning and ecotoxicology tools to engineer sustainable food production systems based on aquaculture. The testbed includes an automated recirculating aquaculture system (RAS), which filters, cleans and recycles water back through a tank, integrated with a real-time ecotoxicology system that studies the effects of toxic chemicals on biological organisms. Because the team includes aquatic organisms in the system, they also intend to develop tools that expand the cyber-physical systems (CPS) technology to the biological domain.

“Combined, all aspects of this project contribute to food production sustainability,” Acevedo says. “In addition to being the most efficient animal protein production system, aquaponics contributes to the reduction of harmful effects on the environment.”

Brackish water aquaponics is of great interest for inland areas far from the coast because it includes products associated with marine resources. The team hopes to demonstrate that it’s possible to repurpose desalination byproducts to produce food, offsetting the costs of treatment while reducing the environmental impacts of those byproducts. This will yield important societal benefits.

Finding options for concentrate management, other than disposal, remains a major challenge to implementing desalination in inland areas. Therefore, results of this project could impact areas with a semi-arid or arid climate, scarce surface water and brackish groundwater. Additionally, the project could affect saline aquaculture producers worldwide, leading to the protection of coastal ecosystems.

“Although aquaponics is becoming prevalent as a means of food production, efforts to develop these systems in brackish groundwater are scarce,” Acevedo says. “This project will contribute to filling this need by understanding how organisms respond to varying salinity and brackish groundwater chemistry. It also stands to impact desalination technology, as it proposes a profitable option for concentrate management.”

A substantial innovation of this research is the development of real-time respirometry — the measure of biological oxygen consumption — which has value beyond this project. By combining it with video tracking and machine learning for a behavioral assessment of toxicity, the team is creating a real-time ecotoxicology system (RTES) powered by artificial intelligence. In addition, consolidating all variables in the AI to help develop models that can be used to design and operate production-scale systems represents an advance in CPS technology.

This project came out of a 2019 experiment the research team conducted in collaboration with the Center for Marine Aquaculture and Stock Restoration at the Federal University of Parana in Brazil. The team tried growing shrimp in the concentrate of two brackish groundwater off-grid desalination pilot systems installed in New Mexico and Colorado. The desalination system being used in this project also evolved from an international award-winning system developed in 2015.