Study On Operating Characteristics Of EGSB Reactor For Treatment Of High Concentration Organic Wastewater

EGSB reactor is a new anaerobic reactor developed based on the UASB reactor,with high sludge concentration,sludge volume,high removal rate of organic pollutants,high resistance to shock loading,small area,low cost advantages,in starch,alcohol,beer,paper making and other industries had many applications,is a hot research in the high concentration organic waste water treatment process,especially in the use of treatment of refractory organic waste water with high concentration.Therefore,it is of great practical significance to study the application of EGSB anaerobic reactor in the treatment of high concentration organic waste water by EGSB anaerobic reactor.This paper based on the laboratory of high concentration organic wastewater as the research object,under the experimental conditions of EGSB anaerobic reactor start-up,domestication of process performance and sludge change,also studied the operating characteristics and rules of biological reactor for treatment of laboratory organic waste water of high concentration.The research contents include EGSB reactor for treatment of multicomponent high concentration organic waste water running effcet and influent concentration,hydraulic retention time,the rising velocity,reaction temperature and other factors.Analysised the changes of the organic components before and after the treatment water by liquid-liquid extraction,GC-MS detection.According to the changes of the organic matter degradation efficiency and degradation of the organic component.Researched the influence of hydraulic retention time of the reactor based on Monod model.The results show that:(1)Taken the sludge from the UASB reactor as activated sludge of EGSB reactor,using artificial waste water to cultivated.The results showed that the first 30 days was sludge adaptation period,the reactor was not stable in this phase,the degradation rate of the organic was in greater volatility,the lowest was only 22.88%,the highest reached 61.48%,the gas production was low,the reactor acidification frequently,53 days after,granular sludge began to form;starting 107 days,the sludge was ellipsoidal,mature,stable performance,the degradation rates of glucose reactor maintained at 93%-97%,the gas production was up to 208.44L/d,the effluent acidity was stable,alkalinity was maintained at about 2600mg/L,VFA/ALK maintained at about 0.15.(2)Used the organic waste liquid collected in laboratory as feed and run 36 days,observed the sludge morphology,found that the sludge had been adapted to the organic waste water and the color of the sludge was bright brown.In the domestication process,when the liquid inlet concentration increase,the treating capacity of the reactor was greatly reduced.When the feed concentration increased to 6500mg/L,the degradation of organic fell to 43%,the gas production down to 62.16L/d,the effluent volatile organic acid content reached 952.47mg/L,the alkalinity of effluent was 3187.31mg/L(CaCO3),continue to improve the concentration,the reactor had the acidification risk.At this point,the reactor had reached the limit of treatment.It was concluded that the maximum range of the EGSB reactor for this kind waste water collected in laboratory was 6500mg/L.(3)The mature granular sludge was analyzed by scanning electron microscopy,found that the sludge was dominated by Brevibacterium in the start-up period,and it was transformed into a combination of filamentous bacteria and bacillus.(4)The optimum process of the EGSB reactor was established based on the study of the influenced factors of the treatment of high concentration organic waste water by EGSB reactor:the influent concentration was 5000mg/L,the hydraulic retention time was 12 hours,liquid flow rate was 5m/h,the temperature was 35 degree.Under the optimum conditions,the operating efficiency of the reactor was as follows:the degradation rate of organic matter was 78.40%,the gas production of sludge was 134.74L/d,the volatile organic acid in the effluent was 364.33mg/L,and the alkalinity was 2986.43mg/L.(5)Used liquid-liquid extraction and GC-MS method to test the water,the results show that the main component of organic waste water was:alcohols,amines,ketones,eaters,nitriles,hydrocarbons,and the effluent was still dominated by the above types of organic compounds,but the quantity had been greatly reduced,indicating the reaction had a great removal effect.(6)Through the analysis of the organic components changes in water,the degradation mechanism was:In the degradation process of organic waste,ketones,amines,hydrocarbons,eaters,organic acid and other substances had degradation priority for simple organic matter in hydrolysis acidification bacteria,and produce organic acid and other products for the acetic acid bacteria to use,the methanogens using acetic acid formation of methane and cell meterial,thus reducing the water quanity of the organic compounds.(7)Used the Monod model to study the degradation kinetics of EGSB reactor,by combining the material balance equation,the Monod model and Linerweaver-Burk method,obtained the Ks and vmax were 3706.62mg/(L·d),1.0532d-1 respectively,the kinetic equations under different hydraulic retention time was:v=1.0532S_e/S_e+3706.62.