Optimization of nitrogen and phosphorus removal from saline wastewater using Halomonas sp. H12 strain

Abstract

Efficient simultaneous nitrogen removal and phosphorus accumulation microorganisms are great significance for the purification treatment of high salt wastewaters containing N and P. In this paper, the processes of nitrogen removal and phosphorus accumulation of Halomonas sp. H12 strain under high salt conditions were investigated. The optimal conditions of nitrogen removal and phosphorus accumulation were examined separately by using response surface methodology. The results showed that the Halomonas sp. H12 strain had high efficiency competent of nitrogen removal and phosphorus accumulation under high salt conditions under both growth stage and non-growth stage. Within 108 h, the rates of the nitrogen removal and phosphorus accumulation reached 78.51% and 49.18% respectively. During 0-84 h, the strain was in the growth stage, and its nitrogen removal rate and phosphorus accumulating rate increased gradually. At 84-108 h, the strain then entered the non-growth stage with its growth reached the maximum. Interestingly in this equilibrium phase, high efficient nitrogen removal and phosphorus accumulation were still carried out with the prolongation of time. Results from this work are of great significance for the purification of industrial wastewaters containing N, P and high salt.