Removal of nitrogen compounds in ornamental aquaculture effluents using Pseudomonas sp. and Bacillus sp. bacteria

Resumen

Abstract– High concentrations of inorganic nitrogen in aquaculture effluents pose a toxic risk to fish production and the environment. In this context, aerobic nitrifying and denitrifying bacteria play a key role. This study evaluated the ability of Pseudomonas sp. and Bacillus sp., isolated from effluents, to reduce ammonium nitrogen, nitrite, and nitrate in wastewater from an ornamental fish farm (Lima, Peru). Four biological treatments were implemented (control, T1: Pseudomonas sp., T2: Bacillus sp., T3: consortium) in aerobic reactors to promote simultaneous nitrification and denitrification processes. The reactors were inoculated with a bacterial concentration of 1.5x107 CFU/ml. During the experiment, nitrogen compounds exceeded optimal levels in the control. In contrast, the bacterial consortium (T3) showed the highest effectiveness, removing nearly 100% of ammonium nitrogen (1.00 ± 0.22 mg/L), nitrite (0.066 ± 0.048 mg/L), and nitrate (16.67 ± 8.17 mg/L) within 96 and 168 hours, respectively. Additionally, T3 maintained stable physicochemical conditions (20°C–23°C, pH 7.47–7.72, DO > 5 mg/L), optimizing its degradative capacity. The results confirm that the consortium of Pseudomonas sp. and Bacillus sp. is effective in removing inorganic nitrogen, standing out as a potential biotechnology for treating and reusing wastewater in ornamental aquaculture.