Achieving partial denitrification with sludge fermentation liquid as carbon source: The effect of seeding sludge

摘要

The partial denitrification (nitrate to nitrite) has been a promising way for nitrate wastewater treatment combined with ANAMMOX system subsequently. This work investigated the effect of seeding sludge on partial denitrification by using sludge fermentation liquid as carbon source, with the sludge taken from: anoxic/oxic reactor (S_A), anaerobic-anoxic-oxic reactor (S_(A-A-O)) and alternately anaerobic sludge fermentation coupling anoxic denitrification reactor (S_(A-A)). The results showed that transient accumulation of nitrite was observed in S_A and S_(A-A-O). However, at the initial nitrate concentration of 30mg/L, a high nitrite of 20.91±0.52mg/L was accumulated under complete nitrate reduction in the S_(A-A) system, which indicated that partial denitrification could be realized. Furthermore, as much as 80% nitrate-to-nitrite transformation ratio (NTR) was achieved in a 108-day operation with inoculating S_(A-A), which illustrated the stability of partial denitrification under long-term operation.