Treatment Low-carbon Source Urban Sewage By Multi-level Step Feed A/O Biological Filter

In traditional biological wastewater treatment process, denitrifying, p uptake process consumption carbon sources. At present the urban sewage carbon source concentration is generally low in wastewater treatment process. How to make full use of its carbon sources is the main subject technology about sewage wastewater nitrogen phosphorus.In this paper, low-carbon source urban sewage was treated, using continuous water smulti-level step feed A/O biological filter on experimental research, examined the research of the system to the major pollutants removal efficiency, nitrification denitrifying rate, the space distribution features of the system and the main influence factors of the system.The results show that:(1)Multi-level step feed A/O biological filter removal of major pollutants in low-carbon source urban sewage, stable and efficient.Effluent COD, TN, ammonia nitrogen respectively less than40mg/l,15mg/l,3mg/l, removal rate can reach85%,78%,96%respectively, effluent TP also lower than0.5mg/L. Effluent was reached "the urban sewage treatment plant emissions standards "(GB18918-2002) in A standard level.(2)N ratio in the same conditions, the TN removal rate of multi-level step feed A/O biological filter was higher than the mud three-step method A/O process in the literature. The removal of TN in multi-level step feed A/O biological filter was77.2%. While mentioned in the literature, the removal of TN in three-sectional A/O process was73～75%.Water was mainly due to multi-level step feed A/O biological filter on the ability of organic matter degradation, the use of more efficient carbon source.(3) All levels of nitrification tank, denitrification tank had strong nitrification, denitrification. The nitrification rate, denitrification rate of the system was higher. Aerobic pool at various levels of system had nitrification comparative completely, effluent ammonia nitrogen average concentration below3mg/l; Oxygen pool at various levels of system denitrification were completely, react to water nitrate nitrogen average concentration below3mg/l.(4)System for the major pollutants removal can achieve better treatment effect in reflux ratio, air to water ratio, hydraulic loading respectively100%,5:1,0.189m3/(m2·h) under1:1:1Water than;When reflux ratio, gas water ratio, hydraulic loading respectively100%,5:1,0.189m3(m2·h), improve water than can reduce the concentration of the effluent TN, make the concentration of effluent TN less than13mg/l.This paper provide a new technology for treatment low-carbon source urban sewage, and smulti-level step feed A/O biological filter has wide application, remarkable economic and environmental benefit.