|DAVIDSON, JOHN - Freshwater Institute|
|SUMMERFELT, STEVEN - Freshwater Institute|
|Straus, David - Dave|
|GOOD, CHRISTOPHER - Freshwater Institute|
Submitted to: Aquacultural Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/2018
Publication Date: 2/1/2019
Publication URL: https://handle.nal.usda.gov/10113/6264786
Citation: Davidson, J., Summerfelt, S., Straus, D.L., Schrader, K.K., Good, C. 2019. Evaluating the effects of prolonged peracetic acid dosing on water quality and rainbow trout Oncorhynchus mykiss performance in recirculation aquaculture systems. Aquacultural Engineering. 89:117-127. https://doi.org/10.1016/j.aquaeng.2018.12.009.
Interpretive Summary: Peracetic acid has been described as a powerful oxidizer capable of producing water quality benefits. This research study used recirculating aquaculture systems (RASs) stocked with rainbow trout to see if doses of peracetic acid could help maintain water quality and prevent off-flavor. We found that water quality was not changed from the control RASs as expected, but water was clearer. It did not help off-flavor problems, but these may have been caused before the fish were put in the study.
Technical Abstract: Peracetic acid (PAA) is an effective water sanitizer for certain aquaculture applications. PAA has been described as a powerful oxidant capable of producing water quality benefits like ozone; however, the water oxidizing capacity of PAA in aquaculture systems and its general effects on fish production require further investigation, particularly within recirculation aquaculture systems (RAS). To this end, a trial was conducted using six replicated RAS; three operated with semi-continuous PAA dosing and three without PAA addition, while culturing rainbow trout Oncorhynchus mykiss. Four target PAA doses (0.05, 0.10, 0.15, and 0.30 mg/L) were evaluated at approximately monthly intervals. A water recycle rate >99% was maintained and system hydraulic retention time averaged 2.7 days. Rainbow trout performance metrics including growth, survival, and feed conversion ratio, were not affected by PAA dosing. Water quality was unaffected by PAA for most tested parameters. Oxidative reduction potential increased directly with PAA dose and was greater (P < 0.05) in RAS where PAA was added, indicating potential for ORP to monitor PAA residuals. True color was lower (P < 0.05) in RAS with target PAA concentrations of 0.10 and 0.30 mg/L. Off-flavor (geosmin and 2-methylisoborneol) levels in culture water, biofilm, and trout fillets were not affected by PAA dosing; although these could have begun building up prior to PAA exposure or in some of the lower doses. Overall, semi-continuous PAA dosing from 0.05-0.30 mg/L was compatible with fish performance and RAS operation, but did not create dramatic improvements in water quality like those expected when applying low-dose ozone.