The Study Of Aerobic Granule Sludge Cultivation With Industrial Wastewater

In view of now most of the studies on aerobic granular sludge were on the laboratory-scale stage on home and aboard and using synthetic wastewaters with simple compositions for experiments, and the height to diameter ratio(H/D) of reactor is very large. In this study, the influent water for experiment was drawed at a chemical factory after anaerobic treatment and the factory was producing hydroxyethyl cellulose, and the seed sludge was from the return sludge of carrier biofilm reactor. We designed two sets of sequential airlift bioreactors with different scales which marked R1 and R2, The reactors were run simultaneously for the cultivation and the pollutant removal efficiency of aerobic granular sludge. Main contents and results are as follows:1. The effective volume of R1 was 80L, the H/D was 4, the flow was 160L/d; The effective volume of R2 was 600L, the H/D was 4 too, the flow was 1.2m3/d. R1 and R2 ran simultaneously and the quality of influent water were the same, organic loading rate was 4kg/m3·d; Small granular sludge which diameter was greater than 0.1mm began to emerge at 14th day. After 26 days, the diameter increased to 0.3mm. At the 50th day of the reaction, the cultivation of aerobic granular sludge in R1 reactor reached to mature phase, and the mass fraction of the granular sludge which diameter were between 1.0～1.5mm was 42%, when the mass fraction of the granular sludge diameter were bigger than 0.25mm was 90%. Small granular sludge which diameter was greater than 0.1mm began to emerge at 37th day. In R2 reactor. After 74 days, the diameter increased to 0.3mm. At the 130th day of the reaction, the cultivation of aerobic granular sludge in R1 reactor reached to mature phase, and the mass fraction of the granular sludge which diameter were between 0.5～1.0mm was 42%, and the mass fraction of the granular sludge which diameter were bigger than 0.25mm was 88%.2. During the formation of aerobic granular sludge, the MLSS in R1 and R2 appeared to have a increased trend after an decline. The MLSS of R1 declined from 4410mg/L to 3080mg/L in 15days, and then rised slowly, at 51th increased to 4290mg/L. The MLSS of R2 declined from 4560mg/L to 2780mg/L in 48days, and then rised to 3860mg/L. at 138th. The SVI30 of R1 declined from 124mL/g to 44mL/g in 50 days straightly and then tended to stabilize. The SVI30 of R2 was 129.6mL/g at the beginning, and declined to 66 mL/g at 128th and trended to stabilize then.3. The removal ratios of COD and NH3-N in R1 were 81% and 71% when R2 was 74% and 65%.