Influential Factors of the Rapid Startup of Nitrosation at Ambient Temperature in SBR for Domestic Sewage

摘要

The nitrosation rate was around 85% after 33 continuous cycles (20d) with the alternative influent of high and low ammonium wastewater in a sequencing batch reactor (SBR) under low oxygen (0.15~0.40mg/L). The growth of nitrobacteria was inhibited successfully which led to steady and high accumulation of nitrite. Factors of accumulation of nitrite were investigated and the effects of DO and pH were analyzed during the startup for nitrosation. The results showed that it could improve the efficiency of nitrosation when DO concentration was increased appropriately. The activity of nitrite oxidizing bacteria (NOB) was recovered gradually when DO was higher than 0.72mg/L. The key factor of nitrosation reaction was the concentration of free ammonia (FA), while the final factor was the concentration of DO. pH was a desired controlling parameter showing the end of nitrification in a SBR cycle, while DO concentration did not indicate the end of SBR nitrification accurately because it increased rapidly before ammonia nitrogen was oxidized absolutely.