Influence of temperature on denitrification of an industrial high-strength nitrogen wastewater in a two-sludge system

Abstract

The temperature effect on denitrification rate of a two-sludge system has been studied. An industrial high-strength wastewater and an industrial by-product containing mainly methanol, as external carbon source, were used in this study. The maximum denitrification rate (MDR) was determined at six different temperatures: 6, 8, 10, 15, 20 and 25°C in batch mode. The temperature coefficient was found to be 1.10 ± 0.01 at temperatures between 10 to 25°C and 1.37 ± 0.01 at temperatures between 6 to 10°C. The MDR obtained in the two-sludge system (0.28 mg N·mg VSS-1·d-1 at 25°C) was higher than the one obtained in a single-sludge system with a similar external carbon source. The COD/N ratio required for complete denitrification in the two-sludge system was approximately stoichiometric, which is 3.7 ± 0.9 mg COD·mg N-1.