Experimental Study On Landfill Leachate Treatment By AT-BC Process

In view of the problems of long acclimation time and poor treatment effect of sludge in the biological treatment of landfill leachate in the middle and old age stages,a small test device was designed based on the special strain Bacillus in the AT-BC process,in order to find a biochemical treatment process suitable for landfill leachate treatment with short culture period,low overall energy consumption and high treatment efficiency.In this paper,the activation and domestication of Bacillus bacteria were carried out.When Bacillus bacteria were cultivated by hot water（75°C）,adding phosphorus source and gradual dilution method,yellow brown flocculent sludge with good activity was quickly cultivated after 16 days,and the removal rates of COD and NH3-N were78%and 69%,respectively.Compared with the domestication and cultivation effects of common activated sludge strains,under the same cultivation conditions,the removal rates of COD and NH₃-N by common activated sludge strains were only 53%and 46%,respectively.This shows that Bacillus has stronger adaptability to high concentration of landfill leachate,and can better remove refractory pollutants in landfill leachate.Secondly,the effects of p H,temperature,organic nutrient solution dosage,dissolved oxygen,ammonia nitrogen concentration and carbon source dosage on the activity of Bacillus were investigated.The results showed that when maltose as carbon source,p H 7.1～8.3,water environment temperature25±2°C,organic biological nutrient solution dosage 2.0～4.0 mg/L,DO>0.3 mg/L,ammonia nitrogen concentration less than 1300mg/L,Bacillus had high biological activity.Finally,a self-made AT-BC process pilot plant was made,and the effects of various factors on the treatment effect of the plant were studied by single factor method after strain domestication and rotary disc filming.The results showed that when the rotating speed was 2.0～3.0r/min,the influent p H was 6.5～8.5,the influent temperature was 25°C,the anoxic temperature of the aeration tank group（1#aeration tank）was 33°C,the dissolved oxygen concentration distribution of the aeration tank group was low（1#aeration tank DO<0.3mg/L）,low（2#aeration tank DO 0.3～0.8mg/L）,high（3#aeration tank DO 1.0～1.5mg/L）,low（4#aeration tank DO0.6～1.0mg/L）,the hydraulic retention time was 60～72h,the reflux ratio of the mixture was 300%～400%,the sludge reflux ratio was 75%,the sludge concentration was 4400～5200mg/L,the sludge age was 18～25d,the dosage of sodium acetate was 500～800 mg/L,the AT-BC process pilot plant was the best,and the removal rates of COD,NH₃-N and TN reached 83%,81%and 66%,respectively.The conclusions can be used as the basis for the parameter values of the AT-BC process applied to the biochemical treatment of landfill leachate.