Effects of Selected Chemotherapeutants on Nitrification in Fluidized-Sand Bioftlters for Coldwater Fish Production

Abstract

Four fish chemotherapeutants, formalin, benzalkonium chloride, chloramine-T, and hydrogen peroxide were evaluated for their effect on the nitrification efficiency of fluidized-sand biofilters. The chemotherapeutants were added at conventional concentrations to two small-scale (2,200 L) coldwater recirculating rainbow trout (Oncorhynchus mykiss) culture systems each containing six fluidizedsand biofilters operating in parallel. Nitrification efficiency of biofilters was calculated before and after chemotherapeutant treatments by determining ammonia removal efficiency at ambient conditions, and also when challenged with a sudden increase of ammonium chloride at a concentration four times that of the ambient total ammonia-nitrogen (TAN). Two formalin treatments in recycle bath mode at 167 and 300 ppm were conducted with only the 300 ppm treatment having a significant negative effect on biofilter nitrification efficiency. Four single benzalkonium chloride treatments of one and 2 ppm were conducted; two static bath treatments and two recycle bath treatments. Of these four tests, only the recycle bath treatments caused biofilter nitrification efficiency to be significantly impaired. Two multiple treatments with benzalkonium chloride were conducted: one static bath treatment and one recycle.bath treatment. These treatments caused ammonia removal efficiency to decrease by 18% in the static bath treatment and by 63% in the recycle bath treatment. Of these two tests, only the recycle bath treatment caused a significant impairment of nitrification. Single static bath and recycle bath treatments with 9 ppm of chloramine-T both resulted in significant impairment of nitrification, as did a 12 ppm multiple static bath treatment. A single static bath treatment with 100International Journal of Recirculating Aquaculture, vol. l, no. 1 61 ppm of hydrogen peroxide caused almost total failure of nitrification within 24 h of treatment but biofilters were able to remove 23% of TAN within 48 h of treatment.

Degradation and effect of hydrogen peroxide in small-scale recirculation aquaculture system biofilters

“…This safe approach to reduce pathogen pressure has the built-in drawback that the bio¢lter potential becomes a retreat. A long-term e¡ect of HP was recorded in Schwartz et al (2000), where the ammonium-degrading e⁄ciency of a £uidized-sand bio¢lter in a small-scale RAS was measured before and after HP exposure. The nitri¢cation e⁄ciency declined from 85% to 1% within the ¢rst 24 h after a 1-h exposure of 100 mg L À 1 HP.…”

“…Schwartz, Bullock, Hankins, Summerfelt and Mathias (2000) is one of few studies dealing with the effects of HP on the nitrifying performance of biofilters in a RAS. Here, a severe inhibition of nitrification in terms of significantly reduced total ammonium nitrogen (TAN) removal was demonstrated following a static bath treatment with 100 mg L −1 HP.…”

“…Knowledge on treatment e⁄ciency and treatment regimes in partial and fully RAS is limited, and potential damaging e¡ects on nitrifying populations in bio¢lters have impeded the use of HP in RAS so far. Schwartz, Bullock, Hankins, Summerfelt and Mathias (2000) is one of few studies dealing with the e¡ects of HP on the nitrifying performance of bio¢lters in a RAS. Here, a severe inhibition of nitri¢cation in terms of signi¢cantly reduced total ammonium nitrogen (TAN) removal was demonstrated following a static bath treatment with100 mg L À 1 HP.…”

Removing organic and nitrogen content from a highly saline municipal wastewater reverse osmosis concentrate by UV/H2O2–BAC treatment

“…The lower removal of nitrogen species in the presence of residual H 2 O 2 was likely due to the suppression of or other detrimental effect of higher concentration of residual H 2 O 2 on the nitrogen-removing bacteria as suggested by Lu et al (2013) who observed an even lower TN removal. Schwartz et al (2000) showed 80% reduction in ammonium removal in a fluidised sand bed filter at a H 2 O 2 concentration of 100 mg L À1 . Møller et al (2010) found that the nitrification process could be moderately affected with a low dose of H 2 O 2 (10-13 mg L À1 ) in a biofilter for a recirculating aquaculture system, thereby reducing ammonia and nitrite removal.…”

Efecto de un Sistema de Producción Química de Oxígeno en Cultivo de Bagre Tigrito (Pimelodus pictus) en Sistemas de Recirculación Sometidos a Interrupción de la Aireación Mecánica

“…En estudios previos se ha reportado que el H 2 O 2 se puede emplear como desinfectante, sin dañar el medio ambiente y sin alterar la salud de los individuos presentes en los SCR (Pedersen y Pedersen, 2011). De igual manera, se ha evaluado su aplicación en biofiltros y se ha evidenciado que no influencia de manera negativa el proceso de nitrificación (Schwartz et al, 2000;Møller et al, 2010). Otros estudios reportan que puede ser usado como fuente de oxígeno para el transporte de peces, desde alevines hasta adultos, mostrando un incremento en la concentración de OD y una mayor sobrevivencia, comparativamente con el tratamiento control de cada uno de los estudios (Taylor y Ross, 1988; Barua et al, 2012).…”