| Molasses yeast wastewater belong to the difficultly treated organic wastewater with the characteristic of high COD concentration,deep brown color,high sulfate concentration and bad biodegradation.Nowadays,there exist the problem of low running efficiency and high running cost on treatment process of molasses yeast wastewater,which restricts the development of yeast industry. In this study,the conventional secondary anaerobic-aerobic biochemical treatment process is regarded as the first time initating reactor and the efficiency of the reactor is investigated in order to improve the biochemical treatment process.as a result,electrolytic previous treatment and surfaceaeration are introduced into the treatment process,which can achieve the optimum effect,and at last,the aerobic effluent is subjected to advanced treatment and the effluent meets the emission standard.It takes 74 days to start the conventional biochemical treatment process,when it will be in steady-state situation.The pH of molasses yeast wastewater is marked up to 7.18 resulting from self-regulation ability of microorganism and then the wastewater is pumped to the secondary UASB-BCO reactor.UASB reactor can degrade COD,color and sulfate and the removal rate are 65.06%,10.88% and 20.9%,respectively, and BCO reactor can also eliminate 8.53% COD and 12.18% color,which inplies that the efficiency and elimination capacity of biochemical reactor is low and the effluent don’t meet the standard of wastewater treatment.The treatment process is improved because of the drawback on treatment efficiency and the technology of electrolytic previous treatment and surfaceaeration are recommended to the treatment process with the purpose of enhancing the biodegradability of wastewater and relieving the loads of post-processing.the ameliorative biochemical treatment process operates well through 110 days debugging and The removal effect is strengthened obviously which accelerates the normal and stable operation of reactor.The BOD5/COD of wastewater is from 0.230 to 0.409 and simultaneously the color removal can get 10% when the wastewater is subjected to the treatment of electrolysis.the surfaceaeration treatment also achieves 14.5%COD removal and 11.52% color removal.after wastewater is gone through the reactor,the majority of biodegradable matters are removed.the results illustrate that 89.6% COD,34.56% color and 60% sulfate are eliminated,which suggests the ameliorative process is more efficient.Aerobic effluent still possesses high color and COD and it need further treatment.in this study,the self-designed O3/UV reactor is applied to treat the aerobic effluent and the factors of reactor are investigated in order to study the operation conditions for efficient of reactor.when the ozone dosage,UV lamp,pH and temperature are arranged at 4g/h,40 w,8.55 and 40℃,respectively,the reactor will be in optimum treatment condition and the color and COD removal can get 93% and 40%.According to the MW distribution measured by GPC,the compounds in raw wastewater are completely disappeared and two new groups are appeared symbolizing lower molecular weight compounds,which demonstrates that the organic compounds with high Mw are cracked into smaller fractions.We can come to a conclusion that O3/UV sysrem is shown to effectively remove the color and COD associated with melanoidins.the potentiality of the O3/UV process as a promising posttreatment stage to remarkablely achieve color and COD remomal and obtain more easily biodegradable wastewater is affirmed.Finally, when subjected to the improved secondary anaerobic- aerobic combined with physical and chemical process for molasses yeast wastewater, the COD, color, and SO42- are from 18569 mg/l, 3.86 and 2215 mg/l to 1000 mg/l, 0.178 and 621 mg/l, respectively.,and the removal efficiency is 95%, 95% and 95% respectively.It affirms that the process is feasible technology for molasses yeast wastewater. |
PDF Full Text Request