(182e) Degradation of Taste and Odor Compounds with Cactus Mucilage Extraction Enhanced Photo-Catalysis Under Solar Light

Recirculating aquaculture systems (RAS) are gaining popularity due to their water savings compared conventional aquaculture. A disadvantage of RAS is that conditions are created for the production of taste and odor compounds. These compounds, such as Geosmin (GSM) and 2-methylisoborneol (MIB), are secondary metabolites created by cyanobacteria and some actinomycetes that cause an earthy musty flavor that can be detected in water at extremely low concentrations The current removal approach for these compounds is to purge them from the fish prior to harvesting, which requires large amounts fresh water or treating the recirculating water onsite. Removal of GSM and MIB can be achieved by conventional adsorption treatment with activated carbon; however, removal efficiency has been inconsistent due to variations in the base of the carbon, adsorption capacity of the media and interactions with natural organic matter (NOM). In recent years, UV-TiO₂ photo-catalysis are getting commonly used to treat odor and tasty compounds in fish water. However, the energy consumption and cost of UV light can be exorbitant and may be unfeasible for many fish farms.

This research will focus on using cactus mucilage extraction enhanced photo-catalytic techniques to improve the taste and odor compounds treatment in the recirculating aquaculture systems under solar light. Cactus mucilage is a biomaterial that used as food source in some countries and it is renewable, biodegradable, easy access and low cost. Previous research has found mucilage extractions are effective for organic contaminate removal. The result has shown that up to 80% removal of MIB and GSM can be achieved in short residence time with our improved mucilage-solar catalyst system. Continued-experiment have been conducted to test the durability of our mucilage-solar catalyst under RAS. The GC-MS analysis has been done to detect the removal rates of GSM and MIB. The X-ray powder diffraction (XRD) has been done to determine the structure/property relationships of the solar catalyst material that lead to the most efficient treatment process.