Insights into two stable mainstream deammonification process and different microbial community dynamics at ambient temperature

How to achieve stable mainstream deammonification is still a huge challenge. In this work, satisfactory nitrogen removal were achieved in a deammonification granular sludge reactor (R1, 0.42 ? 0.03 kg N / (m3?d)) and a mixed flocculent with granular sludge reactor (R2, 0.39 ? 0.04 kg N / (m3?d)) at ambient temperature (21?28 ?) . The good adaptability of anammox bacteria (Candidatus Jettenia) to ambient temperature ensured its efficient activity (0.84?1.54 mg N/(g VSS?h)). The overexpression ammonia monooxygenase gene abundances in ammonia oxidizing bacteria (Nitrosomonas) was also predicted. The inhibition of hydrazine and the competition of denitrifying bacteria (Denitratisoma) to nitrite nitrogen, leading to a low Nitrospira relative abundances (0.2%2.1%) . It was also found that R1 was more resistant to the unfavorable condition. For R2, higher Denitratisoma abundances (9.2%-18.5%) and predicted metabolic pathway abundances related to carbon metabolism were observed.

Automated summary

This study successfully achieved stable deammonification at ambient temperature, with insight into microbial abundance and activity in the reactors providing potential factors influencing system efficiency.