| Nowadays,anaerobic fermentation technology was considered to be one of the most important methods for cassava alcohol wastewater treatment,which can not only degrade wastewater to the renewable energy biogas,but also protect the environment.However,there were still some problems for the anaerobic fermentation,because the substantial solid matter of the wastewater would lead to reduce the hydrolysis rate and conversion rate,which would cause less biogas production and lower utilization rate.Thus,it was very important to increase the resource utilization rate from cassava alcohol wastewater.Firstly,the anaerobic digestion experiment by the high efficiency compound bacteria and other bacteria was compared,and the fermentation performance of four inoculums were evaluated,the result indicated that the high efficiency compound bacteria had the advantage in biological degradation of wastewater with high cellulosic soild matter.Secondly,in order to improve the degradation rate of cellulosic matters,the high efficiency compound bacteria was stressed by adaptive acclimation.Then,the anaerobic digestion characteristics and the change of microbial community dynamics was studied during the cassava alcohol wastewater treatment by continued CSTR anaerobic reactor under the thermophilic temperature condition,which was inoculated the high efficiency compound bacteria,in addition,this study had built the kinetics model in order to obtain the optimum operation parameters.Lastly,the UASB was used for the CSTR effulent treatment reactor,which in order to increase the energy convertion rate from the cassava alcohol wastewater.The main conclusions were as follows:The experiment evaluated the anaerobic performance of four inoculums for the cassava alcohol wastewater treatment.The results showed that the crude fibre degradation rate in the thermophilic floc sludge group,mesophilic compound sludge group,mesophilic granular sludge group and mesophilic floc sludge group were 25.8%,41.5%,16.1% and 29.4%,respectively,and biogas production rate were 188.8,109,53.7 and 182 mL/gTCODadded,respectively.The maximum enzyme activity of cellulose and hemicellulase in mesophilic compound sludge group were 48.2 U and 51.3 U on the 9th day,respectively,while the mesophilic granular sludge group had the lower enzyme activity of 5.5 U on the 3rd and 9.8 U on the 5th day,respectively.The adaptive acclimation experiment study showed that it could improve the daptation and performance of cellulosic matters degaradation bacteria after stress.After 8 days,the maximum enzyme activity of cellulose and hemicellulose in each group were 34.3 U and 20.7 U in group a;45.2 U and 24.0 U in group b;34.7 U and 22.1 U in group c,respectively.The crude fiber degradation rate in the three groups was 34.8%,40.4%,38.5%,respectively.By a long period of CSTR running,the total removal rate of TCOD was 70~75%,methane content maintained at about 48%,the biogas generation rate was 0.22 L/gTCOD when the volume loading rate was 14 kgCOD/(m3·d).Xylanase activity and cellulose enzyme activity reached its maximum value of 42.1 U and 30.2 U,respectively when the reaction temperature was 55?.In addition,the dehydrogenase activity reached the maximum value of 80.1 TF?g/(h·mL)when the volume loading rate was 12 kgCOD/(m3·d).The high throughput sequencing analysis showed that the dominate bacteria includes Defluviitoga ?Ruminiclostridium-1 and Ruminiclostridium under the thermophilic condition,which played a very important role in cellulosic degradation performance during the anaerobic process.The UASB was used as the second treatment stage to further deal with the effluent of CSTR,and the cassava alcohol wastewater was treated by the method of gradual increase the volume loading rate under the temperature of 35?.After about 60 days' operation,the experiment results showed that the effluent concentration of TCOD and SCOD were 1327.9,551.2 mg/L,the removal rate of TCOD was 84.1% and the biogas production rate was 0.31 mL/g TCOD when the loading rate was 7 kgCOD/(m3·d). |
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