A NEW TYPE OF HIGH-RATE SLUDGE ANAEROBIC DIGESTER
A pilot experiment on thermophilic digestion of excess activated sludge in a new type of high-rate anaerobic digester----Internal circulation anaerobic digester was conducted. The digester is modified from Internal Circulation Anaerobic Reactor treating wastewater. It consists of reaction zone, settling zone, riser and downcomer. Some of the generated biogas is pumped back to the button of the reaction zone to intensify the recirculation in digester. The recirculation could significantly improve the mass transfer. In the experiment digestion with HRT of 5.5 days was combined with pyrohydrolysis at 60℃ with HRT of 1 day as pretreatment. The average total VSS and SS removals of the system was 60.8 and 45.8％, and the average biogas rate was 12.8m3/m3sludge (96％ water content) under organic loading of 1.39 kgVSS/(m3d). Hydrodynamic shear condition is crucial for this digester. The optimal range of superficial liquid velocity would be 0.3-0.4m/h and could be easily controlled by backflow biogas flow rate. The results show that the new digester employing upflow conception could effectively improve reaction rate as compared to the results from literature. It has good degradation ability of sludge and buffer ability to resist various common shock loadings. Pyrohydrolysis directly reduced sludge with the average VSS and SS removals of about 20 and 10％ and significantly increased biogas rate by 27-116％ in this experiment.
Internal circulation anaerobic digester thermophilic anaerobic digestion excess activated sludge
J. WU P.J. ZHAO L.TIAN L. SHI H.C. SHI
State Key Joint Laboratory of Environment Simulation and Pollution Control, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, P.R.China
国际会议
北京
英文
244-249
2010-05-17（万方平台首次上网日期，不代表论文的发表时间）