Aquaculture 2022

February 28 - March 4, 2022

San Diego, California

A NOVEL ADVANCED OXIDATION TECHNOLOGY THAT RAPIDLY REMOVES GEOSMIN AND MIB FROM WATER AND SIGNIFICANTLY REDUCES ATLANTIC SALMON DEPURATION TIME

 

 Terence P. Barry*, Ramsey Kropp, Casey Grimm, Kyle Woolever , and Steven T. Summerfelt

 

Exciton Clean, LLC

807 Liberty Drive, Ste 110

Verona, WI 53593

terry@excitonclean.com

 



Atlantic salmon (Salmo salar ) reared in RAS  can  accumulate off-flavor chemicals  (e.g., geosmin and 2-methylborneol, MIB)  that  reduce  fish marketability.  A  solution to this problem is to hold the fish in separate depuration systems that are flushed with  clean water in a single pass or operated with limited water recirculation.  During depuration the fish are not fed and c an  lose  significant weight and value.

 We tested the effects of a new technology called the Exciton Advanced Oxidation Process® (eAOP® )  on the removal of geosmin and MIB from 18 m3  depuration tanks at a commercial Atlantic salmon RAS operation. eAOP® is a unique technology that works using multiple  mechanisms of action including UV photolysis, titanium dioxide  photocatalysis, electrolysis, and UV/peroxide AOP.  Geosmin and MIB were measured by GC /mass spectroscopy.

In p reliminary  chemical spiking experiments without makeup water flow, the eAOP® reactor  rapidly  eliminated all of the  geosmin and MIB in  the  water in 2- 3 hrs (Fig. 1). An actual depuration  experiment was then conducted to determine the effects of eAOP® on the total purge time. Market-sized (3.8-4 kg) fish  from a single harvest  were split between control (normal flow-through depuration procedure) and eAOP® -treated 18 m3 purge tanks. W ater and  triplicate  fish flesh samples were collected  from each tank  every two days for ten days.

Geosmin levels in both groups followed first order removal kinetics with the following parameters: control tank fish, k = 0.092 day-1, R2 = 0.91, half-life = 7.5 days; eAOP® , k = 0.147 day-1, R2 = 0.95, half-life = 4.7 d. Thus, geosmin removal from the fish in the eAOP®-treated tank was 60% faster than in the control tank , and the normal 10-day depuration time was reduced to 4-5 days. We conclude that eAOP®  can be used to treat purge water to significantly reduce total depuration times while using less water.