Effect Of Methane Fermentation On The Technque Of Alcohol Fermentation Couple With Methane Fermentation

In this paper, for the problem of manufacturing water consumption and heavy pollution burden in existing cassava fuel ethanol, as"Zero Population"as the goal, a cycle process which we named"ethanol fermentation couple with methane fermentation"using digestive juice as ingredients water for next batch alcohol fermentation was established. In the cycle, finding and eliminating bottleneck factor was focused, effect of methane fermentation on the cycle process and the law of some important materials in the cycle were studied also.UASB was used for distillation wastewater treatment in this experiment. The experimental course contains two phase. The first stage, distillation wastewater was treated by thermophilic anaerobic UASB, then the digestive was used as ingredients water for cycling.7 batch alcohol fermentation and 6 batch methane fermentation were executed as the cycle process doing, at the same time, alcohol distillation wastewater's nitrogen,phosphorus,COD,sCOD,sulfate and thermophilic digestive juice's nitrogen,phosphorus,COD,sCOD,acetic,propionic,butyric,conductivity,pH were tracked and monitored. The results are as follows:1 Alcohol distillation wastewater's sulfate,COD,sCOD and nitrogen are accumulation. sulfate from 1.01 g/L up to 2.65 g/L, COD from 105939 mg/L up to 128973 mg/L, sCOD from 59875 mg/L up to 78414 mg/L, total nitrogen from 3.05 g/L up to 5.47 mg/L, soluble total nitrogen from 1.75 g/L to 3.98 g/L. .No accumulation of phosphorus, total phosphorus,soluble total phosphorus and PO43--P fluctuate at 0.25 g/L, 0.2 g/L, 0.14 g/L respectively.2 Thermophilic anaerobic effluent's sCOD,nitrogen,acetic and propionic were accumulation. sCOD from 5231 mg/L up to 12067 mg/L, soluble total nitrogen from 0.67 g/L up to 3.58 g/L, acetic fluctuate with the load volume, the maximum up to 5.03 g/L, propionic accumulated to 6.15 g/L, conductivity from 0.75×104μs ? cm-1 increased to 1.2×104μs ? cm-1 and fluctuated at it..3 The time alcohol fermentation from 48 h extending to 96 h, the yield of alcohol was no obvious change by reusing thermophilic anaerobic digestive and fluctuate at 10.5%.In the second stage, to solve the problem of materials accumulation and fermentation time extending, mesophilic anaerobic treatment was used and Fe2+ was inputted in distillation wastewater. In addition to monitoring indicators of the above continue, thermophilic and mesophilic anaerobic effluent's sulfate and ammonium,colority of distillation wastewater were monitored also. At the end of the experiment, to verify the important of Fe2+ in degrading sulfate and removing the toxicity of sulfide, stopping inputting Fe2+ in distillation wastewater was done. Using the water above continue, 14 batch alcohol fermentation and 13 batch methane fermentation were executed in the cycle. the experimental results are as follows:1 The time of alcohol fermentation and alcohol yield fluctuate at 48 h and 10.5% respectively. There are no obviously effect on alcohol fermentation time and alcohol yield of reusing mesophilic anaerobic digestive. 2 There are no materials accumulation in alcohol distillation wastewater. sulfate stabilize at 1.2 g/L, COD and sCOD stabilize at 120000 mg/L and 10000 mg/L, total nitrogen and soluble total nitrogen stabilize at 3 g/L, 1.7 g/L, total phosphorus,soluble total phosphorus and PO43--P stabilize at 0.24 g/L, 0.17 g/L, 0.12 g/L, the colority of . distillation wastewater is stable.3 There are no materials accumulation in thermophilic anaerobic effluent. Sulfate stabilize at 0.35 g/L, sCOD stabilize at 12000 mg/L, soluble total nitrogen and ammonia stabilize at 1.5 g/L and 1.1 g/L respectively, soluble total phosphorus and PO43--P stabilize at 10 mg/L and 5 mg/L, acetic and propionic fluctuate at 0.5 g/L and 3 g/L , conductivity from 1.5×104μs ? cm-1 up to 3.0×104μs ? cm-1 and fluctuating at it.4 There are no materials accumulation in mesophilic anaerobic effluent. Sulfate stabilize at 0.18 g/L, COD and sCOD stabilize at 2000 mg/L and 1000 mg/L respectively, total nitrogen,soluble nitrogen and ammonia stabilize at 1.2 g/L,1 g/L,1 g/L respectively, total phosphorus,soluble total phosphorus and PO43—P stabilize at 10 mg/L,5 mg/L and 4 mg/L respectively, VFAs less than 500 mg/L, the conductivity from 1.0×104μs ? cm - 1 up to and stabilized at 2.0×104μs ? cm-1.Conclusion: mesophilic anaerobic digestive reuse as alcohol fermentation's ingredients water is feasible, Fe2+ have an important role in degrading sulfate and removing the toxicity of sulfide.