Modular Advanced Oxidation Unit for Water Recycling in Aquaculture and Other Industries

In recent years, recirculating aquaculture systems have gained ground and are revolutionizing the seafood industry by treating and reusing tank water, allowing for increased control of water quality and ability to optimize growth conditions, and are opening the door for inland areas to engage in seafood production. These recirculating systems require highly efficient water treatment that removes problematic constituents and disinfects wastewater effectively and reliably. Although current recirculating aquaculture technology addresses the major issues of solid waste, biological contaminants, and depleted oxygen levels, it does not adequately address the accumulation of recalcitrant organics, nutrients, and metals that build up over time. Among these are the difficult-to-destruct taste and odor compounds that have plagued aquaculture for decades, costing producers significant time, labor, and money. This project will aim to replace the traditional ultraviolet-only disinfection stage of these systems with a low-cost, reliable modular advanced oxidation unit that combines peracetic acid with ultraviolet light that will significantly reduce the contaminants—including costly taste and odor compounds—without drawbacks seen in other advanced oxidation processes, while also removing arsenic, phosphorus, manganese, and iron. Initial data indicates that peracetic acid may be very effective as an alternative oxidant and disinfectant due to its ability to delay biological growth on membranes without producing toxic residuals that could harm fish. Phase I feasibility goals are to achieve 75% average removal of contaminants and 99.99% bacterial reduction through a lab-scale unit that will be fabricated and tested. Data obtained will be used to develop a larger unit and test the unit full scale on recirculation water at an operating aquaculture center. Data obtained will then analyzed to identify improvements and prepare for Phase II work. This unit will effectively disinfect while also having the potential to sufficiently address other difficult-to-degrade compounds, including pharmaceutically active compounds and per- and polyfluoroalkyl substances, which will be explored in a Phase II. A unit that can effectively treat and prevent taste and odor compounds that have plagued the aquaculture industry will clear the way for recirculation-based aquaculture to thrive in the United States, securing seafood supply and enabling greater access to fresh fish for consumers. The unit’s ability to destroy other difficult-to-degrade compounds has the potential to be especially useful within other fields beyond aquaculture, including agriculture and municipal wastewater treatment.