Effect of temperature on the kinetics of wastewater disinfection using ultraviolet radiation

Abstract

The effect of temperature on the performance and kinetics of the UV disinfection process was investigated using a single lamp annular UV reactor. The reactor was operated to disinfect secondary treated domestic wastewater at 10, 20, 30, 40 and 45°C. The first order rate model and the student i‐test were used for data analysis. The effect of temperature in the normal operation range of most treatment plants, 20–40 °C, was found not to be statistically significant on the kinetics of the UV disinfection process. The kinetics of the UV disinfection process was highly affected by system operations at extreme temperatures (i.e., at 10 and 45 °C). In a temperature range of 20–40 °C, the inactivation rate constant of fecal coliforms was about 590 cm²/μW.sec. A relatively high inactivation rate constant of 770 cm²/μ W.sec was noted when the temperature of the disinfected wastewater was increased to 45°C. The inactivation rate constant at 10 °C was relatively low at 350 cm²/μ W.sec. The minimum UV dose required to meet the Meteorology and Environmental Protection Administration fecal coliform standard of 200 organisms/100 mL, for effluent discharge, was about 180 /μ W.sec/cm².