Study On Molassesalcohol Wastewater By Hydrolytic Acidification-distillation-aerobic Process

Molasses alcohol wastewater is a typical hard-biodegradable industrial organicwastewater with high concentration of organic substance and high color degree. Rawsewage could pollute the natural water or cause soil acidification and compaction. Inthis study, hydrolytic acidification-distillation-aerobic treatment was selected to treatmolasses alcohol wastewater&explore the removal efficiency of organic substanceand the recovery efficiency of volatile fatty acid. These measurements and analysescould provide theory guidance to realize the resource utilization of molasses alcoholwastewater by generating biogas with recycled volatile fatty acid.In order to explore the influence of initial pH value on the effect of hydrolyticacidification, different organic loadings of molasses alcohol wastewater were studiedin the experiment of hydrolytic acidification. Some studies have found that the pHvalue of hydrolysate increased at first and then decreased with the time slowly. While,biodegradability of hydrolysate were all enhanced in varying degrees. The removalrate of total sugar decreased with organic loading and the removal rate of COD firstincreased and then decreased with organic loading after hydrolytic acidification. Theeffect of hydrolytic acidification of molasses alcohol wastewater got the best at the pHvalue of7.00. At this point, the removal rate of COD got the maximum of44.34%with organic loading of1.07gCOD/gMLVSS. And the value of BOD/COD was alsoincreased from0.40to0.77.Hydrolysate, which was got by hydrolytic acidification when molasses alcoholwastewater was handled with the initial pH value of7and organic loading of1.07gCOD/gMLVSS, was processed in the experiment of distillation at different initial pHvalue, such as4.50,5.00and5.50, to discuss the removal effect of organic substance,the recovery effect of VFAs and the relationships with energy consumption. It showedthat the amount of VFAs which was withdrawn as distillate, the recovery rate ofVFAsand the removal rate of COD of hydrolysate increased with decreasing initial pHvalue at the same time. Moreover, the effect of initial value of pH on the amount ofVFAs and the recovery rate of VFAs was gradually decreased with increasing time.Otherwise, cumulative effective energy consumption decreased with decreasing theinitial value of pH at a certain recovery rate of VFAs or removal rate of COD. Furthermore, the amount of VFAs withdrawn from hydrolysate got the maximumduring the0-5min. And the removal effect of COD was clearly effective at15minwith less energy consumption. It can be reached to55.95%of VFAs,59.23%of CODwith319.32103kJ of energy consumption when unit volume hydrolysate wasdistilled at initial pH value of4.50,15min.Compare the effect of aerobic treatment of hydrolysate distilled for15min withhydrolysate processed directly, it could suggested that the removal rate of total sugarof hydrolysate distilled was lower than that of hydrolysate undistilled. But judgingfrom the overall treatment effect, the effect of distillation on the removal effect oftotal sugar of molasses alcohol wastewater was not obvious. And it can be reached to81.71%of COD employing acidification-distillation-aerobic treatment which was16.63%higher than that undistilled. Moreover, the COD concentration of formercould decrease to277.72mg/L that can be discharged directly. And the former couldrealize the recovery of VFAs in the process of distillation. While the latter needfurther processing with the COD concentration of530.45mg/L.