Effect of microalgae on ammonia removal in aquaculture wastewater by fluidized bed. In：R. Hirano and I. Hanyu (eds.)

Abstract

When the granular activated carbon (GAC) fluidized bed was used for the treatment of aquaculture wastewater, the concentration of ammonia was reduced from the range of 0.22 to 2.32 mg/1 to the range of 0.04 to 1.80 mg/1, under designated operating conditions. If only acclimated microalgae were introduced into the GAC fluidized bed, the attached microalgae in the fluidized bed would become deficient in oxygen instead of having net oxygen production under light condition. However, the concentration of ammonia appeared to decrease via the uptake of microalgae. When GAC together with the attached biofilm was taken out from the fluidized bed and then immediately introduced into the other three small-scale fluidized beds, the efficiency of ammonia removal increased with the increasing amount of attached microalgae, except when the attached amount was too much and/or the retention time of attached microalgae was too long.