Impact of Elevated Refinery Wastewater Temperature on Nitrification Rates in the Activated Sludge Process

摘要

This paper summarizes prior research undertaken to assess the impact of elevated wastewater temperature on nitrification rates in the activated sludge process. While not an exhaustive review, this summary presents observed data and correlations of environmental conditions (temperature, pH) with nitrification rates. While most of the reported research was conducted with wastewater temperature typically encountered with municipal wastewater (<30°C), some of the reported observations on nitrification rates are made in the 35°C to 45°C range, the temperature range where the performance of temperature-sensitive nitrifying organisms is reported to decline. This is also the temperature range that is common for refinery wastewaters, particularly those refineries located in warm weather, tropic regions, and where current governmental environmental policies require near complete nitrification of elevated ammonia-containing refinery wastewater, and in some cases, total nitrogen removal to less than 10 mg/L. This paper explores the impact of temperature and pH on nitrification rates and presents an empirical model for nitrification in activated sludge systems that can be used to optimize nitrification design for refinery wastewaters, particularly for refineries located in warm-weather climates.