Research on Greenhouse Gas Emission Reduction Methods of SBR and Anoxic Oxic Urban Sewage Treatment System

Abstract

With the rising awareness of environmental protection, more sewage treatment plants have been built. However, this is also one of the main sources of greenhouse gas emissions. This study carried out a series of sewage treatment experiments to analyze the factors affecting the greenhouse gas emissions of the two commonly used treatment processes in the current urban sewage treatment: the A/O and SBR methods. The experimental results showed that the total amount of greenhouse gases emitted by the A/O method was 415.63 gCO2-eq/m3, and the total amount of greenhouse gases emitted by the SBR method was 879.51 gCO2-eq/m3. The N2O emission factor in the A/O method experimental group was 0.76% of the nitrogen content in the influent. In the aerobic section, when the content of dissolved oxygen was in the range of 1.30~2.10 mg/L, and the content of dissolved oxygen was 1.90 mg/L, the minimum N2O emission factor was reduced to 0.29% of the nitrogen content of the influent. In the SBR experimental group, the ammonia oxidation rate of sewage decreased rapidly as the temperature decreased, thus affecting the discharge rate of N2O. At 25 °C, the biological enzyme activity of nitrifying bacteria was higher, thus promoting denitrification and generating more greenhouse gases. The research results provide reference for strengthening the management of sewage treatment plants and reducing greenhouse gas emissions from sewage treatment plants.