Determination of required water flow rate for effective bioremediation in recirculating aquaculture systems using constructed microbial mats

Ricardo Jimenez Montealegre, Jorge Zamora Castro, Gerardo Zúñiga Calero


DOI: https://doi.org/10.3856/vol43-issue1-fulltext-20

Abstract


The effect of water flow rate was evaluated on the microbial mats efficiency to remove total ammonia nitrogen (TAN, NH4+-N+ NH3-N), nitrite (N-NO2-), nitrate (N-NO3-) and orthophosphate (P-PO4-3) in a pilot recirculation system for the culture of the Pacific white shrimp, Litopenaeus vannamei. Four water flow rates were evaluated during 40 days: 5.2 ± 0.3 (A), 6.6 ± 1.3 (B), 8.4 ± 0.3 (C), and 12.2 ± 0.7 (D) L min-1. The concentrations of TAN and nitrites were significantly lower (p< 0.05) in the higher flow treatments (C and D) and always showed values ​​below 0.6 mg L-1 and 0.7 mg L-1, respectively. The concentrations of nitrate increased in all treatments through the experimental period; however, the concentrations were statistically higher in treatments with higher flow rate (7.1 mg L-1). Orthophosphate removal was not significantly different between treatments (p> 0.05). The accumulation of orthophosphate in the system was relatively constant, reaching final concentration ​​of 4.63 ± 0.76 mg L-1. The growth rate of shrimp remained close to the expected value of 0.7 g week-1. This study showed that the water flow rate has a significant effect on the microbial mats capacity for the bioremediation of ammonium and nitrite in recirculating systems. It is recommended to continue with the identification of other variables that could affect the optimal functioning of microbial mats in RAS.


Jimenez Montealegre R, Zamora Castro J, Zúñiga Calero G. Determination of required water flow rate for effective bioremediation in recirculating aquaculture systems using constructed microbial mats. Lat. Am. J. Aquat. Res.. 2016;43(1). Available from: doi:10.3856/vol43-issue1-fulltext-20 [Accessed 22 Jan. 2019].
Jimenez Montealegre, R., Zamora Castro, J., & Zúñiga Calero, G. (2016). Determination of required water flow rate for effective bioremediation in recirculating aquaculture systems using constructed microbial mats. Latin American Journal of Aquatic Research, 43(1). doi:http://dx.doi.org/10.3856/vol43-issue1-fulltext-20