Study On Cassava Ethanol Wastewater Treatment And Sludge Reduction

Sludge treatment and disposal in wastewater treatment became more and more important. If the treatment was not efficient, it would not only increase the cost of wastewater treatment, but also even cause secondary pollution of the environment, so sludge treatment and disposal was particularly important. In addition, sludge treatment was difficult part in wastewater treatment process, some technologies were not mature enough, or some processes were higher cost. Through the study on the sludge from aerobic treatment of Cassava ethanol wastewater, to take the effect of sludge discharge.The study could guide the practical engineering application with practical significance.pH of Cassava ethanol wastewater was as low as 4.0, however COD was up to 10000 mg/L～70000 mg/L. The study found that its biodegradability was well, therefore adopted UASB-SBR combination Process. In Anaerobic reactor, the temperature was controlled at 37℃～38℃by water bath, HRT 2d, each reaction cycle of treatment 7L. Aerobic treatment were carried out at room temperature, dissolved oxygen were at 2mg/l～4mg/L. Aerobic sludge returned to the adjustment pool to retreat wastewater. While sludge returnedto the anaerobic reactor, the excess sludge were reducibly treated, producing biogas utilization.During the research process, through the UASB anaerobic treatment process, the COD removal were about 90%, effluent pH maintained at 7.0 to 7.3,anaerobic reaction system VFA/ALK were 0.1 to 0.3, In the final research, observation found that anaerobic sludge were granule. In the first aerobictreatment process, the COD removal rate couldeach 90%, while in the secondary aerobic treatment process, the COD removal rate could be only around 70%, but the final effluent water could be standard. The end of each aerobic treatment cycles, it could produce about 2L without precipitation. Study found that without regulation of sludge precipitated the best. Also sludge with 1:3(sludge: Cassava ethanol wastewater) returned to adjustment pool.the pH of water rose from 3.86 to 4.39. The COD removal rate could be more than 20%, and SS removal rate could be 20%. It also found that the pretreatment water were helpful to the sludge removal, COD removal rate increased about 2.2%, increasing gas production. But when the sludge back tothe anaerobic, COD removal rate were reduced, but the gas production of anaerobic phase were almost unaffected. In the whole process, there was no excess sludge to discharge.