Study on the efficacy of sodium alginate gel particles immobilized microorganism SBBR for wastewater treatment

In this paper, for the first time, sodium alginate gel spheres prepared by N, N-methylene bisacrylamide cross-linking method were used as immobilized microorganism carriers. And they were combined with sequencing batch biofilm reactor to obtain sodium alginate -SBBR, used to treat simulated urban domestic sewage. After 52 days of start-up, the removal rate of chemical oxygen demand and ammonia nitrogen could reach 87% and 97%, respectively. The abundance of denitrifying bacteria and anaerobic bacteria on sodium alginate gel particles increased, including Dokdonella and Aridibacter, whose abundances were 11.12% and 15.20%, respectively. It proved that the carrier provided a partial hypoxic and anaerobic environment for microorganisms. When dissolved oxygen concentration was 2.5 mg/L, the average removal rates of oxygen demand and ammonia nitrogen were both above 88%. Under three modes, the average removal rates of total nitrogen were 70.98%, 80.04%, 72.38%, respectively. Dissolved oxygen concentrations were both uneven in a single particle and entire reactor, which was conducive to the occurrence of SND.