Microbial Community Dynamics and Nutrient Removal Performances in A2O System Using Ultrasonic-Disintegrated Sludge Supernatant as Internal Carbon Source
Ultrasonic-disintegrated sludge supernatant was supplemented into A2O system to assess the effects on nutrient removal performances and microbial community changes. In this experiment, easily biodegradable organics accounted for 50.6% of sludge supernatant, indicating its potential for biological nutrient removal. Simultaneously, during two-month operational period, the ammonia nitrogen (NH4+-N) and total phosphorus (TP) removal efficiencies improved to 92.3% and 93.5% from75.6% and 53.4%. Duo to the application of sludge supernatant, two microbial phyla, Proteobacteria and Actinobacteria, were primarily responsible for the biological nutrient removal. In particular, the sludge supernatant was selective for ammonia oxidizing bacteria Comamonas sp. and denitrifying phosphate accumulating organisms Sphingobacterium.