Rapid Improvement of Denitrification Performance of Embedded Activated Sludge and Community Analysis

Abstract

The purpose of this study was to rapidly improve the denitrification packing activity in the denitrification pond sludge of sewage plants, to realize the engineering application of embedding immobilization, and to explore the characteristics of the microbial community of the embedding packing. The effects of different C/N ratios, temperature, and pH on the activity of embedding filler were studied by batch experiments, and the biological community characteristics of embedding filler were studied by high-throughput sequencing. Results showed that the embedding packing in C/N to 10, the temperature of 30℃, and pH of 7.5±0.3, resumed 5.37 mg·(g·h)-1 of the initial activity after 7 days. Under the optimized culture conditions of C/N ratio of 10, temperature of 25℃, and pH of 8.0, the specific rate of denitrification can be increased by 15 times to 80.17 mg·(g·h)-1 after 15 days, and stabilized at that level. SEM results showed that there were a large number of mass transfer channels inside the embedding fillers, and that the bacteria grew well as clusters in the encapsulated fillers. The high throughput sequencing showed that the denitrifying function of Thauera and Thermomonas were 24.27% and 8.23% respectively, which ensured the high efficiency of denitrifying nitrogen removal. The rapid proliferation of Thauera dominant bacteria and Thermomonas under optimal culture conditions was the main reason for the rapid increase of packing activity.