Performance of different biofilters in a recirculating system for rainbow trout farming

Abstract

Objective. To evaluate the performance of different biofilters in a recirculating aquaculture system (RAS) for trout farming. Materials and methods. It was used a 1m3 plastic tank for fries farming; fabric bags to solids retention; a submersible pump; a constant water level and flow distribution box; six up flow biofilters in 3” PVC tube; sand of D10=0.45mm as carrier. The reactors were operated at local temperature and with hydraulic retention time (HRT) of 11 min, the biofilters were inoculated in the next way: R1-Control: RAS water; R2-Fish culture farm sludges; R3- Water from aerated lagoon of Antanas landfill (AL); R4-Aquarium sediments; R5- Aerated lagoon of AL sludges; R6-Sludges from sulfidogenic reactor of AL. The weight gain (WG) and the food conversion (FC) were evaluated, some physic-chemical parameters were monitored and the nitrogen and suspended solids removal efficiency were evaluated. Results. The WG of the cultured animals was 1.58 g/d and the FC was 1.41. There were no differences for ammonium and nitrite removal between the reactors; the average removal efficiencies were: ammonium 4.78%, nitrite 27.2%, nitrate 32.3%, suspended solids 37.5%; R4 and R5 reactors presented the best performance on nitrate removal, with average efficiencies of 47.4% and 42.8%. R3 presented the best SS removal with an average of 58.2%. Conclusions. The RAS water treatment system guaranteed appropriated liquid quality conditions for trout farming; the most efficient reactor for removal of the different forms of nitrogen was the inoculated with the aerated lagoon of AL sludges.RESUMEN Objetivo. Evaluar el desempeño de diferentes biofiltros en un sistema de recirculación (SRA) para cultivo de trucha arcoiris. Materiales y métodos. Se utilizó: un tanque de 1m3 para cultivo de alevines, bolsas de lienzo para retención de sólidos, bomba sumergible, caja de nivel constante y distribución de flujo, seis biofiltros en tubo de PVC de 3”, arena con D10=0.45mm como medio soporte. Los biofiltros se operaron a temperatura ambiente y con tiempo de retención hidráulica (TRH) de 11 min, se inocularon así: R1-Control: Aguas del SRA; R2-Lodos estación piscícola; R3-Agua Laguna aireada relleno sanitario Antanas (RSA); R4-Sedimentos acuarios; R5-Lodos laguna aireada RSA; R6-Lodos reactor sulfidogénico RSA. Se evaluó la ganancia de peso (GP) y la conversión alimenticia (CA), se monitorearon parámetros físico-químicos y se evaluó la eficiencia de remoción de nitrógeno y sólidos suspendidos. Resultados. La GP de los animales fue de 1.58 g/d y la CA de 1.41. No hubo diferencias para remoción de amonio ni nitritos entre reactores; las eficiencias medias de remoción fueron: amonio 4.78%, nitrito 27.2%, nitrato 32.3%, sólidos suspendidos 37.5%. Los reactores R4 y R5 presentaron mejor remoción de nitratos, con eficiencias medias de 47.4% y 42.8%. El R3 reportó la mejor remoción de SS con promedio del 58.2%. Conclusiones. El sistema de tratamiento del agua en el SRA garantizó condiciones de calidad del líquido, apropiadas para el cultivo de la trucha; el reactor más eficiente para la remoción de las formas de nitrógeno evaluadas fue el inoculado con lodos de la laguna aireada del RSA.

Potential applications of biological filtration media in changing water properties and subsequent effects on common carp (Cyprinus carpio) in recirculating aquaculture systems

“…The recommended pH for aquaculture systems is between 6.5 and 8.5, while data indicate the optimum pH for nitrification in system is 8.5 (Tyson et al, 2004). Statistically significant differences in nitrate removal were obtained for each treatment type with the average efficiency exceeding 42% (Sánchez-O et al, 2016). Suhr and Pedersen (2010) Quality of water, food availability and physiological status of fish either directly or indirectly influence their blood constituents (Iqbal et al, 1997).…”

“…The recommended pH for aquaculture systems is between 6.5 and 8.5, while data indicate the optimum pH for nitrification in system is 8.5 (Tyson et al., 2004). Statistically significant differences in nitrate removal were obtained for each treatment type with the average efficiency exceeding 42% (Sánchez‐O et al., 2016). Suhr and Pedersen (2010) stated that the removal rates of ammoniacal nitrogen in biofilters are highly dependent on environmental and operational parameters such as flow distribution and backwash regimes.…”

Evaluation of anaerobic and anoxic reactors installed in serial to treat fish tank effluent

“…Beli et al (2010) observed a reduced turbidity in 87% operating an aerobic/anaerobic combined treatment using anaerobic baffled reactor followed by a sand filter. Sánchez et al (2016) achieved 58.2% in suspended solid removal with a biofilter using sand as Evaluation of anaerobic and anoxic reactors installed … Rev. Ambient.…”