(234h) Removal of Taste and Odor Compounds with Cactus Mucilage Beads Adsorption and Advance Oxidization: Scale up Applications for Continues Recirculating Aquaculture Systems

Recirculating aquaculture systems (RAS) are gaining popularity due to their inherited water savings compared conventional aquaculture. In RAS, the water is treated and recirculated, reducing fresh water inputs and volume of wastewater discharges. In addition, they provide more environmental control for fish growth, which in turn can result in higher production rates. However, one of the disadvantages of RAS is the production of off flavor compounds. These compounds, Geosmin (GSM) and 2-methylisoborneol (MIB), are secondary metabolites created by cyanobacteria and some actinomycetes. Such compounds induce an earthy musty flavor in fish that can be detected by the human senses at extremely low concentrations. One of the most common processes to remove such compounds involves purging them with fresh water. However, this technique requires large amounts of treated water or treating the water onsite. Removal of GSM and MIB can be achieved by conventional adsorption treatments with activated carbon.

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 extraction can be used as dispersant in different cases, such as oil spills. Different concentrations and types of mucilage extraction can be combined into Alginate beads that are proved to be effective for removal of GSM and MIB due to adsorption mechanism. Further, modified UVis-TiO₂ photo-catalysis oxidization can be combined with the mucilage beads column to keep enhancing the total removal effectiveness of such odor compounds. It is found this combined system can possibly achieve more than 90 percent total removal of MIB and GSM, which may significantly benefit the fish production and market.

In the end, the system will be scaled up and tested in the Mote Marine Laboratory & Aquarium in order to further demonstrate its efficiency in a pilot unit for treating the wastewater from their fish production.