Achieving partial denitrification using carbon sources in domestic wastewater with waste-activated sludge as inoculum
2019
Shi, Liangliang | Du, Rui | Peng, Yongzhen
Partial denitrification (PD, nitrate → nitrite) using carbon sources in domestic wastewater with waste-activated sludge as inoculum was firstly achieved in this study. Through controlling influent pH at about 9.0 and anoxic reaction time of 1 h in the start-up, the nitrite (NO2−-N) production reached as high as 25.2 mg/L, with influent nitrate (NO3−-N) of about 30 mg/L and chemical oxygen demand (COD) to NO3−-N ratio of 5.9. Furthermore, PD performance remained stable without pH control during subsequent operations. Efficient NO2−-N production was closely related to the consumed amount of readily biodegradable COD (Ss) fraction, with optimal Ss/NO3−-N ratio of about 3.5. Thauera (19.1%), norank_f__Xanthomonadaceae (5.2%), and Thiobacillus (5.0%) were enriched during the 208-day operation, which may be responsible for high NO2−-N production. These findings provided a novel strategy for promoting mainstream PD/Anammox application, without additional nitrite-accumulating denitrifying sludge and external carbon sources.
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