The Study Of The Using Yeast And EM Activated Sludge Technology For The Treatment Of The Diosgenin Production Wastewater

Diosgenin is the raw material of a kind of highly valuable hormone medicine, Whichis widely applied to these medicines of resisting inflammation,contraception,relievingpain,anesthetizing,curing coronary heart disease ,etc. The international market demands ofDiosgenin is very large ,which leads to the growth of the number of manufactures ofDiosgenin in China .However ,the Diosgenin production wastewater which is characterizedby high color(7000 times), low pH(1— 2) and high organic concentration(COD=20000— 60000mg/L) can be hardly treated in a reasonable cost .Most of the Diosgeninmanufactures discharge the wastewater directly because there is no totally feasible method oftreating it now. This has done great harm to the water and soil environment near themanufactures , The treatment of Diosgenin production wastewater becomes a new difficultyof industrial wastewater treatment . Yeast is a kind of fungi .Distributing of yeast indicates that after the natural selectionfor along time , yeast fit on the surroundings of containing high concentration sugar ,highconcentration carbon ,or high infiltration pressure, which makes it possible to apply to thetreatment of the high concentration organic wastewater ,And the Diosgenin productionwastewater has the characteristic of great acidity ,high organic matter concentration, whichmainly ingredients are hydrochloric acid ,starch ,moreover ,its content of sugar is reallyhigh .So in order to reduce the pollution degree of the organic waste and gain the SCP byusing the waste as a resource ,we can make the yeast grow in the Diosgenin productionwastewater by controlling the factors. In the study the laboratory-scale continuous treatments of the Diosgenin productionwastewater used yeast. The biochemistry test of yeast indicated that under thecondition:pH5.0,temperature 28℃　,handling time 28 hours ,inoculation 10% term, the CODof the wastewater removal rate is 70% finally, and selects the best yeast strains combinationfrom many kinds of mixed yeast strains, it includes: Sal.carlsbergensis Hanser , Rhodotorularubra(Demme)Lodder , Candida tropicalis. The best yeast strains were inoculated to abiological contact oxidation reactor, and the reactor was used to treat the Diosgeninproduction wastewater . Under the COD load range from 2.0-19.2kg/m.d ,28℃ ,HRT12h ,DO=4.5mg/L,the COD removal rate was over 70%.On other hand, the CODremoval rate will decrease sharply when the treatment system is in short of DO. Variation oforiginal wastewater pH has the important influence on the COD removal rate , but it seemedto have no apparent influence on the pH of effluent water, which keeps the rang of6.0— 7.0.The optimum pH for the growth of yeast was found to be in the rang of 4.5— 5.5.The effluent wastewater contained high concentration of yeast bodies, which contentincreased with the organic concentration (COD) of the wastewater . The effluent wastewaterusing yeast was treated by EM-Activated sludge, which contents great of aerobic andanaerobic microbiology .Using SBR reactor , the results showed that the COD removal ratecan reach 90% finally. Moreover , a series of exporting experiments of the coagulation purify study showed theeffect is small .So the Diosgenin wastewater treatment is not suitable to apply the coagulationpurify method .