Treatment Of Municipal Wastewater With A Pilot-Scale Anoxic-Aerobic SBR

The standard of nitrogen discharge in wastewater was controlled more and more strictly with severe water pollution and eutrophication question occurred and the sense of environmental protection enhanced. The wastewater techniques developed gradually from the period of COD removal to simultaneous, nitrogen removal.The experiment about simultaneous nitrification denitrification(SND) was carried out operated with municipal wastewater by sequencing batch reactor (SBR). Some factors that effect SND were studied particularly. The mechanism of SND was analysised too.When the granular sludge SBR was applied to treat municipal wastewater, the average removal efficiencies of COD, NH4+-N, TN were 83.0%,86.0%,36.5%, respectively. Although the influent concentration varied a lot, the active sludge SBR still had good removal performance. The active sludge SBR had a certain ability to adapt shock loadings. Analysis of typical cycle showed that the active sludge has some nitrogen removal performance but not very good. When the low concentration of urban sewage is treated, in order to reach a higher nitrogen removal, it may take additional carbon.In a lab-scale anoxic-aerobic SBR, high organic loading is benefit for SND. The influent DO controlled in the range of 2.0~2.5 mg/L is good for maintain sludge stabilization and the nitrogen removal. During the trial conditions, the main mechanism of the system is micro-environment theory and biological theory. In the initial reaction, the micro-environment is the main, and the reaction later is the biological theory-driven.