Biological treatment of a high strength nitrogenous wastewater

Abstract

Bench‐scale studies were conducted to investigate nitrification of low and high strength nitrogenous wastewater. Two parallel completely mixed activated sludge reactors were operated over a wide range of mean cell residence times (MCRT) ranging from approximately 2.2 days to 21.0 days. Synthetic wastewater consisting of bactopeptone nutrient broth and ammonium sulfate was fed to the bench‐scale reactors. The feed to Reactor 1 (R‐1) was maintained at a COD:TKN ratio of 6.07:1 whereas feed to R‐2 was maintained at a C0D:TKN ratio of 0.65:1. Observed specific nitrification rates in R‐l ranged 0.037–0.11 mg N/mg MLSS‐day at 20°C, whereas in R‐2, observed specific nitrification rates ranged from 0.13 ‐ 0.38 mg N/mg MLSS‐day at 20°C. Nitrification and carbon removal were both inhibited at MCRTs of 7.9 days or greater in R‐2.

Key words:

• Nitrification
• activated sludge
• bench‐scale