Evaluating the capacity of aquaculture ponds for biological nitrogen removal: The roles of microbial acclimation, aeration management, and supplementation with organic carbon and probiotic bacteria

Aquaculture ponds are a common method for rearing aquatic animals that can be sustainable when managed appropriately. This study aimed to investigate the capacity of aquaculture pond ecosystems to remove nitrogenous wastes by managing parameters that can influence the nitrogen cycle, including microbial acclimation, aeration management, and the supplementation of organic carbon or probiotics. The findings reveal that enhancing indigenous microorganisms through pond pre-acclimation is an effective strategy for alleviating nitrogen accumulation. With pre-acclimation, total ammonia nitrogen (TAN) and nitrite were readily removed. In contrast, non-acclimated ponds experienced TAN at considerably high concentrations for aquaculture standard. Oxygen was produced in ponds through microalgal photosynthesis, which helped maintain safe dissolved oxygen levels within pond ecosystems. The application of intermittent aeration combined with microalgal oxygenation effectively met the oxygen demands while conserving energy. However, organic carbon and probiotic supplementation resulted in nitrogen removal similar to those observed in non-supplemented ponds. Prolonged nitrite accumulation exceeding safe thresholds for shrimp was observed in supplemented ponds with whiteleg shrimp, lasting for 13 days. Meanwhile, ponds that included the pre-acclimation step exhibited a reduced duration of nitrite accumulation. The organic carbon and probiotic supplementation hence may not be essential for controlling water quality in aquaculture ponds.