Study On Treatment Of The Diosgenin Wastewater By MBR And Its Membrane Fouling

With the rapid development of saponin industry,Wastewater from diosgenin industry has seriously affected the ecological environment.The environmental problems are increasingly serious in recent years in our country.For this reason,state and regions establish the increasingly stringent sewage discharge standards.treatment of diosgenin industry wastewater influencing the development of diosgenin industrsy.Because of its unique advantages,MBR is widely applied to the treatment of domestic sewage and industrial wastewater,but its treatment of diosgenin industry wastewater is not very clearly and research reports about membrane fouling problem are more scarce.In this study,the integrated aerobic membrane bioreactor was used to deal with the anaerobic effluent of the diosgenin wastewater UASB treatment process,membrane fouling processes and the pollutant removal effect are investigated under different fluxes,then Membrane flux recovery under different cleaning methods preliminarily analyzed.The research results provide a theoretical basis for MBR treatment of diosgenin industry wastewater.The main research results are as follows:(1)During the Starting phase: The test Setting HRT was 24 h,Complete Sludge Retention,DO was at 2.5-2.8mg/L,The influent pH value in 6.5-7.2,The temperature at 15-22?.Because of the inadaptability of microbes,so the removal rate of the pollutants is low.The removal rate of COD and ammonia nitrogen was only 77.11% and 64.72%.After the entire response system is already in stable state,the average removal rates of COD,ammonia nitrogen,of the reactor were 91.68% and 74.42% respectively.The average effluent concentration of COD and ammonia nitrogen is 97.09 mg/L and 20.82 mg/L respectively and the outflow meets the Discharge Standard of Water Pollutants for Sapogenin Industry(GB20425-2006)and The Discharge Standard of Yam Diosgenin Cleaner Production(DB61/T424-2008)under the optimal conditions.(2)Membrane had an excellent retain capacity to organic matter of liquid from sludge storage.The removal effect of pollutants is different under different membrane fluxes.It has great influence on the treatment of macromolecular pollutants COD and TP,but has little influence on the treatment of small molecular pollutants ammonia nitrogen.With the increase of membrane flux,the removal rate of COD and TP decreased,but the removal rate of ammonia nitrogen has little relation with membrane flux.(3)Different development trend of membrane fouling under different membrane fluxes.If the imposed flux is within critical flux zone,The three step phenomena of membrane fouling(initial Phase,slow membrane fouling and high membrane fouling)appeared.If the imposed flux around the critical flux,The rapid development of membrane pollution in a short period of time and the three step phenomena of membrane fouling also appeared.When the permeate flux was above the critical flux zone,The rapid development of membrane pollution in a short period of time and the three step phenomena of membrane fouling not appeared.(4)Sludge concentration,the content of EPS,the content of proteins and polysaccharides in EPS,the content of SMP and the content of polysaccharides in SMP had obviously positive correlation with membrane fouling rate.The content of proteins in SMP had obviously poor correlation with membrane fouling rate.the result shows that polysaccharides and proteins in EPS and polysaccharides in SMP have a positive impact on membrane fouling.Membrane had an excellent retain capacity to organic matter of liquid from sludge storage.(5)The paper concludes by 8 different membrane cleaning methods:Chemical membrane cleaning is better than ordinary membrane washing,alkaline solution membrane cleaning is better than acid solution membrane cleaning,ultrasonic membrane cleaning is better than ordinary membrane washing,combination of acid and alkaline membrane cleaning is better than only use acid or alkalin membrane cleaning.