Research On Treatment Technology Of Wastewater From Glycerol Production By Fermentation With Canna Edulis Ker

Wastewater from glycerol production by fermentation with Canna edulis Ker comes from the process of drenching raw materials, glycerol extraction process, fermentation process and the process of equipment-washing. Except that from glycerol extraction process, the wastewater from other three processes is easy to be biodegradable. In this study, the combined system with pretreatment, anaerobic biotreatment(upflow anaerobic sludge blanket, UASB)and aerobic biotreatment (sequencing batch reactor, SBR) was developed to treat wastewater from glycerol fermentation. On the basis of experiments of coagulation, Fenton's reagent oxidation and micro-electrolytic method, the best method of pretreatment of wastewater from glycerol extraction process was obtained. And then mixed by wastewater from other process, it is treated by UASB-SBR process. And the effluent can meet the national discharge standards. Before the wastewater from glycerol extraction process was biotreated, the organic components in it before and after pretreatment was analyzed by the method of LC/ESI-MS and GC/MS respectively, in order to validate the effects of pretreatments of Fenton's reagent oxidation and possibility of further biotreatment. The major conclusions of this thesis were shown as following:1.The pretreatment of wastewater from glycerol extraction process with the high COD by coagulation were studied . The results show that when PAC and PAM were used as coagulants and their feeding amount are 200 mg/L and 60 mg/L, respectively, and COD removal efficiency is 28.2 percent.2.The pretreatment of wastewater from glycerol extraction process with the high COD by Fenton's reagent were studied. The best technical conditions were that: the ratio of COD to hydrogen peroxide is 2.0, the ratio of ferrous ion to hydrogen peroxide is 0.3, reaction time is 2 h, the frequency of H2O2 practice was 2. The results show that the COD removal efficiency is to 70.1 percent. The value BOD5/COD increases from 0.202 to 0.568, and the bioactivity of the wastewater is largely raised, and the biodegradability of the wastewater is largely enhanced.3.The pretreatment of wastewater from glycerol extraction process with the high COD by micro-electrolytic method were studied. The best technical conditions are that: the ratio of Fe-carbon is 40:8, reaction time is 100min. The results show that the COD removal efficiency is to 67.4 percent. The value BOD5/COD increases from 0.202 to 0.436, and the bioactivity of the wastewater is raised. 4. Comparing the three methods, Fenton's reagent oxidation is selected as the best method of pretreatment of wastewater from glycerol extraction process.5. The method of LC/ESI-MS and GC/MS were used respectively to analyze the organic components of the wastewater from glycerol extraction process before and after pretreatment. It demonstrated that through pretreatment, the molecule of organic components became small, and the structures became simple. 6. Wastewater from glycerol extraction process pretreated then was mixed by wastewater from drenching raw materials and fermentation process, and was treated by mesophilic UASB reactor. The results showed that: through 140 days' operation after inoculation of granular sludge, the volumetric COD loading of the reactor reached from 0.5kgCOD/m3·d to17.80kgCOD/m3·d, the influent COD of UASB reached from 1538.5mg/L to 6894mg/L, the COD removal efficiency was reached 81.6 percent. The results demonstrated that through the pretreatment of non-degradable organic wastewater and long-time cultivating of sludge, inhabiting effect of remained substances was almostly eliminated and had no apparent side-effect on anaerobic digestion.7. SBR was used to treat the mixture of the effluent of UASB reactor and wastewater from the process of equipment-washing. The determinate parameters are: flow-in 1 h, aeration 6h, settling 1h, flow-out 0.5h and unused 1 h, the total periods was 10.5h. 8. It was workable to treat wastewater from glycerol fermentation by the process of Fenton's reagent oxida...