The influence of temperature fluctuation on the stability of partial nitritation applied for reject water treatment

The influence of sudden and gradual temperature fluctuations on the stability of partial nitritation applied for the treatment of reject water containing ammonium nitrogen (NH₄⁺-N) in the range of 1000 –1400 mg/dm³ was investigated. It was found that a sudden decrease in temperature from 24.3 °C to 14.3 °C and 15.8 °C significantly affected the stability of the process. No negative effect was recorded after a sudden temperature decrease from 24.3 to 17.4 °C. It was also found that during a gradual temperature decrease from 24.3 °C, process stability was negatively affected at 12.7 °C.