Inhibition of Denitrification in Activated Sludge by Nitrite

• Published in: Water environment research Vol. 69; no. 6; pp. 1086 - 1093
• Main Authors: Glass, Charles, Silverstein, JoAnn, Oh, Jeill
• Format: Journal Article
• Language: English
• Published: Alexandria, VA Water Environment Federation 01.09.1997; Blackwell Publishing Ltd
• Subjects: ACTIVATED SLUDGE; Applied sciences; Biological and medical sciences; Biological treatment of waters; Biomass; Biotechnology; DENITRIFICATION; Environment and pollution; Exact sciences and technology; Flasks; Fundamental and applied biological sciences. Psychology; Groundwater; Industrial applications and implications. Economical aspects; Industrial wastewaters; INHIBITION; Nitrates; NITRITE; Nitrites; Nitrogen; Pollution; Research Papers; Suspended solids; Wastewater; Wastewaters; Water treatment and pollution; Activated sludge; Industrial waste water; Nitrites; Denitrification; Inhibitor; Waste water purification; Experimental study; Biological purification
• ISSN: 1061-4303; 1554-7531
• DOI: 10.2175/106143097X125803

Nitrite inhibition of denitrification was investigated using activated sludge that had been adapted to a wastewater containing moderately high levels of nitrate (1 350 mg/L as N) and salinity (40 000 mg/L total dissolved solids). After adaptation, the activated sludge was used to study pH effects on nitrite inhibition of denitrification over a range of 15 to 2 100 mg/L nitrite nitrogen (${\rm NO}_{2}\text{-}{\rm N}$). A pH range of 6 to 8 was used. Using a zero-order model, it was found that the denitrification rate for 250 mg/L${\rm NO}_{2}\text{-}{\rm N}$increased from 0.001 to 0.02 mg N/mg mixed liquor suspended solids (MLSS)·h as pH increased from 6 to 8. Denitrification rate reduction at the lower pH was probably caused by the accumulation of the species nitrous acid (${\rm HNO}_{2}$), and the threshold inhibitory concentration for${\rm HNO}_{2}$was estimated to be low: less than 0.02 mg/L${\rm HNO}_{2}\text{-}{\rm N}$at pH 6. Mixed liquor suspended solids concentration appeared to have no effect on nitrite inhibition of denitrification.