Research On Treating Of High Concentration Organic Wastewater By Aerobic Granular Sludge In Two-Stage SBR

In this study, aerobic granular sludge technology was combined with two-stage SBR process, investigating the treatment capacity of high strength loading by the two-stage SBR system.The first part presents the study on the cultivation of aerobic granular sludge. Both of the two SBR reactors (R1, R2) were most similar, R1 was inoculated by 75% activated sludge and 25% aerobic granular sludge, and R2 was total inoculated by activated sludge. R1 and R2 both finished granulation preliminary after 18 days and 30 days, respectively. The particle size distributions were similar, majority between 0.3mm~0.6mm. After 58th day, particle size of granular sludge in R1 and R2 reached upon 0.6mm, some were bigger than 1.5mm. The results showed that adding mature granular sludge play a positive role in the sludge granulation and reduce about 2/5 of the time.The second part introduces the study on the acclimation of aerobic granular sludge for the sake of COD and nitrogen degradation respectively in the two reactors by feeding in definite concentration and controlling operating parameters. When the two-stage reactors were connected, the influent COD and NH3-N concentration was 1600 mg/L and 80mg/L, respectly. After 27 days continuous operating, the COD removal rate was over 98%, and the average removal rate of TN reached 80.2%. This test showed that the problem of nitrification reaction restrained by high COD concentration was solved by making two types of micro-organisms of different functions grow under their appropriate biological environment.The third part studies the starch wastewater treatment by the two-stage SBR, meanwhile considering the changeable of influent COD and ammonia nitrogen concentration. The results demonstrated that COD removal rate only varied between 91.5% and 94.7% when C/N changed from 12.3 to 30. However, with the increasing of influent COD and C/N, the total nitrogen removal rate was rising; when C/N was higher than 15, the TN removal rate was over 75%. In a word, the proper C/N for the two-stage system was between 25 and 30.