Study On The Influence Factors And Engineering Application Of Treating Fruit Juice Wastewater By Vertical Anaerobic Baffled Reactor

Fruit juice wastewater has a high organic content,and with the development and expansion of fruit juice processing industry,it has become a highlight of the aquatic environment pollution problem.The concentration of pollutant in the wastewater generated during the production of fruit juice is very high,and the fluctuation of wastewater quality and quantity greatly changes.In order to remove contaminants and reduce pollution onto the surrounding water environment effectively,special experiment has been studied and applied to the actual project.Based on the mechanism of VABR reactor and the actual engineering application background,laboratory research was carried out and the effect of environmental factors and operational factors onto the performance of VABR were investigated.Then,a combined process composed by anaerobic + aerobic treatment was used to treat juice wastewater,and the result was applied and confirmed by virtue of actual project.The main results were as follows:1.Experiments on simulated juice wastewater samples,using VABR reactor in laboratory,were tested at medium temperature(35 ~ 39 ?).The reactor was inoculated anaerobic granular sludge,and the highest COD influent concentration was 21858mg/L,the highest proportion of juice contribution in the influent COD was 86.3%,with a COD removal of over 92% at this stage.2.Juice wastewater was treated by VABR reactor,and the influence of some factors onto VABR performance,such as volume load,hydraulic load,effluent reflux ratio,influent alkalinity and influent C: N: P value,were investigated.The results show that the VABR reactor could work well when it operated under the conditions as following: HRT of 30~50h,effluent reflux ratio of about 600%,influent alkalinity of 1300 mg/L,influent C: N: P of 400: 5: 1.3.Furthermore,the effluent of VABR was treated by the aerobic process of SBR,and the removal efficiency of COD promoted much more.When the influent COD concentration was about 300~1400mg/L and the HRT of 24 h,the removal ratio of COD was more than 90%.The combined process,secondary anaerobic(VABR)+ anoxic/aerobic treatment process,was adopted to treat actual industry wastewater from one juice production enterprise.The wastewater quantity was 150m~3/d,and the wastewater qualities were as follows: the influent COD concentration of 10000~20000mg/L and the p H value of 4~6.The results show that the COD removal ratio after the stage of VABR was about 90% and the COD concentration of the final effluent after the whole process was less than 100mg/L when the combined process was operated with the conditions below,the volume load of 14.3 kg CODcr/(m~3/d),alkalinity of about 1300 mg/L,COD: N: P of 300~ 400:5:1,adding a certain amount of trace elements to promote metabolic activity of anaerobic microorganisms.