Treatment of seawater for rotifer culture uses applying adsorption and advanced oxidation processes

Abstract

ABSTRACT. The use of live feed is common in aquaculture processes due to its nutritional advantages, and rotifers comprise one of the most used feeds in finfish aquaculture. However, bacteria present in water used for rotifer culture are a significant source of infection and consequently diseases could cause mortality in fishes. Advanced oxidation process (AOPs) are methods that may be useful to eliminate bacterial infections present in aquaculture wastewater and may allow the reuse of this water. Therefore, the prospect of using different advanced oxidation processes to inactivate Vibrio spp. and total bacteria cultures (TCB) present in this kind of water was evaluated. In particular, UVc/O3/H2O2, UVc/H2O2 and O3/H2O2 and the adsorption process were applied to seawater coming from a fish farming tank. The results obtained were highly promising because it was possible to inactivate 100% of bacteria present in the seawater when UVc/ozone/hydrogen peroxide and UVc/hydrogen peroxide were applied, needing around 20 and 80 min for Vibrio spp. and total culturable bacteria inactivation, respectively. These results are justified due to the strong action between H2O2 in the presence of UVc, which may produce a large amount of hydroxyl radicals. Nevertheless, when ozone/hydrogen peroxide was applied, total inactivation of bacteria did not occur. Also, an interesting relationship between bacteria inactivation and oxide reduction potential of seawater was observed during the process. Rotifers put in water after the treatment did not suffer behavior changes (swimming) and no mortalities were observed. Keywords: rotifers, bacteria, UV irradiation, ozone, hydrogen peroxide, aquaculture.Tratamiento de agua de mar para el cultivo de rotíferos mediante procesos de adsorción y oxidación avanzados RESUMEN. El uso de organismos vivos como alimento es común en la acuicultura, debido a sus ventajas nutricionales. Los rotíferos constituyen uno de los alimentos principales en el cultivo de peces. Sin embargo, las bacterias presentes en aguas utilizadas en el cultivo de rotíferos son una fuente importante de infección y pueden causar enfermedades y mortalidad en peces. Los procesos de oxidación avanzados son métodos útiles para eliminar bacterias presentes en aguas residuales de la acuicultura, permitiendo su reutilización. Se evaluó la inactivación de Vibrio spp. y bacterias cultivables totales presentes en aguas residuales de la acuicultura a través procesos de oxidación avanzados. Particularmente, se estudió la aplicación de UVc/O3/H2O2, UVc/H2O2 y O3/H2O2 junto a procesos de adsorción aplicados a agua proveniente de un estanque de cultivo de peces. Los resultados obtenidos son muy prometedores debido a que fue posible inactivar el 100% de bacterias presentes cuando se utilizó UVc/O3/H2O2 y UVc/H2O2, requiriendo 20 y 80 min para la inactivación de Vibrio spp. y bacte- __________________ Corresponding editor: Ricardo Prego 780Latin American Journal of Aquatic Research rias cultivables totales, respectivamente. Estos resultados se expl...

Assessing Microplastics and Nanoparticles in the Surface Seawater of Venice Lagoon—Part I: Methodology of Research

“…The oxidizing agent is able to digest organic matter more efficiently than NaOH and HCl, with little to no degradation of possible polymers. It was reported that the HO• is very useful in removing natural organic matter, having the advantage of being non-selective [62,63].…”

Treatments of orange‐spotted grouper (Epinephelus coioides) against Cryptocaryon irritans with •OH, ClO2 or HCHO: Survival, physiological and histological response

“…The hydroxyl radical (•OH) is a potent oxidant without selectivity, and it has been shown to inactivate pathogens such as Vibrio spp., Leishmania major and Pavlova viridis (Dolat et al, 2020; Nam‐Koong et al, 2020; Poblete‐Chavez et al, 2016). Our previous research (unpublished) showed that •OH produced by strong ionization discharge combined with water jet cavitation effect could inactivate C. irritans in vitro.…”