[Nitrite accumulation in ammonia-rich organic wastewater]

Nitrite accumulation in CSTR reactor for the artificial ammonia-rich organic wastewater was studied in this paper. It was focused that the effect of C/N to nitrite accumulation and NO(2-) -N : NH(4+) -N in the effluent under the condition of 35 degrees C, dissolved oxygen(DO) 1.5-2 mg/L, hydraulic retention time (HRT) 1 day and pH 8. The results showed that organic carbon was benefit to nitrite accumulation when C/N was lower than 0.42 with NH(4+) -N concentration being 360 mg/L; The suitable C/N for SHARON-ANAMMOX process was in the range of 0.17-0.34;The pH value decreased 0.2-0.4 while organic carbon was added to the artificial ammonia-rich wastewater, the pH value of the effluent of SHARON reactor was suitable for ANAMMOX when C/N was lower than 0.5. With C/N increased, the COD removal rate decreased from 90% to 44% and then stabilized at 82%, which was correlated to an increase of both biomass and organic content increased while organic carbon was added to the artificial ammonia-rich wastewater which can be attributed to the heterotrophic bacteria, at the same time small flocks was formed.