Research on the short-range nitrification SBR process of low carbon ammonia nitrogen wastewater in rare earth mining area

SBR process was used to treat low-carbon ammonia-nitrogen wastewater from rare earth mining area. Acclimation and cultivation of activated sludge, the effect of aeration volume, aeration time and C/N ratio on short-cut nitrification system were investigated. The experimental results showed that the system had an ammonia nitrogen removal rate of nearly 92%, and annitrite nitrogen accumulation rate of more than 90% at the temperature range of 28±1 ℃, with an aeration volume of 65 L/h and a pH of 8, after the sludge was domesticated and cultivated for 69 days. The sludge was detected by high-throughput sequencing before and after it was treated by short-cut nitrification. The analysis results showed that the microbial species in the sludge decreased after the start-up of short-cut nitrification. Nitrosomonas was the dominant species in the sludge, accounting for 11.5% of the total species. When aeration volume was increased to 120 L/h and this condition was kept for 7 days, the nitrite nitrogen accumulation rate decreased to 82%. When C/N ratio was kept between 3.5 and 7.6, the removal rate of NH4+-N in the system could stay about 95% and the accumulation rate of NO2-N was above 93%. Excessive aeration would destroy the short-range nitrification system, and the nitrite nitrogen accumulation rate would drop to 48.89% if excessive aeration last for 8 days.