Aquaculture effluent treatment with ammonia remover Bacillus albus (ASSF01)

Abstract

Ammonia toxicity in water bodies is a global problem. Different approaches have been adopted to get the ammonia concentration in water back to permitted level (0.5 mg L−1 for aquaculture and 5 mg L−1 for environmental discharge). The existing techniques are elaborate and time consuming, often not economically viable. This study reports a single unit packed bed biofilm reactor-based treatment of Aquaculture Effluent (AE) and non-AE using a pure culture of Bacillus albus ASSF01 from environmental origin as inoculum. The strain could reduce an initial ammonia concentration of 1.7 mg L−1 to 4.7 mg L−1 to a final ammonia concentration of 0.5 mg L−1 within 12–16 h while that of 27 mg L−1, 47 mg L−1 and 100 mg L−1 to 5 mg L−1 within 42 h, 48 h, and 98 h under immobilized condition respectively. Upon scaling up the operation to 9.5 L at ambient temperature, the strain could maintain its efficiency along with simultaneous reduction of nitrite from 0.30 mg L−1 to the accepted level of 0.01 mg L−1. The parameters optimized during batch mode operation using Response surface methodology were also applicable for continuous mode operation. The isolate under immobilized condition could remove ammonia at a concentration of 7.92 mg kg−1 of matrix from Luria Bertani broth while 41.6 mg kg−1 of matrix from minimal medium indicating it to be suitable for environmental application. This study reports a rapid, single unit bacterial biofilm based stable continuous mode treatment strategy for ammonia removal from effluent ensuring environmental protection.