Effect of Aerating Frequency on Stabilizing Process of Aerobic Bioreactor Landfill

This paper researched the effect of aeration frequency on stabilizing process of the aerobic bioreactors, coded A1, A2 and A3 under the condition that the total amount of oxygen supplied by aeration was same. A1 was operated at aerating-to-break-operating ratio of 1:5, that aerating was 2 hours and intermittent operating lasted 10 hours. A2 was operated at ratio of 1:3, aerating for 2 hours and intermittent operating for 6 hours. A3 was aerating without break. The results indicated that: (1) the pH values of leachate in A2 and A3 were increasing above 8.0 quickly and fluctuated around pH 8.5 on the 28^th day. And the pH of leachate in A1 increased slowly near to 8.0 up to the 59^th day. (2) COD of leachate in three bioreactors reached the maximum values around the 10^th day, and then dropped gradually. COD of leachate produced in A2 dropped rapidly to 6000 mg/L up to the 42^nd day and that in A3 declined to 6400 mg/L on the 59^th day. COD in A1 was above 3000 mg / L before the 56th day and did not decrease to 8000 mg / L until the 66^th day. (3) the concentration of ammonia nitrogen in reactor A2 and in reactor A3 decreased below 10.0 mg/L on the 28^th day and after the 56^th day respectively. For A1, the concentrations of ammonia nitrogen fell down below 10.0 mg/L during 95 days to 105 days. (4) On the whole filling process the rate of deposition in reactor A2 was highest than others, and that in A1 was lowest. The garbage settlement in A2 also stabilized firstly. In summary the aerating frequency of 1:3 performed better on garbage filled degradation, which the pH of leachate would be stable quickly, the remove rate of COD and concentration of ammonia nitrogen were highest.