The Research Of Pretreating Landfill Leachate Using Adsorbent

Landfill leachate is a kind of organic wastewater with high concentration and complicated components; it contains lots of poisonous and harmful substances. Landfill leachate has effect on environment and people's lives in varying degrees. At present, the most common methods of landfill leachate treatment are physico-chemical treatment and biological treatment. Physico-chemical treatment is pretreatment, biological treatment is the main process.This experiment mainly studied on pretreatment by choosing mineral rich and cheap diatomite, zeolite and kaolin as adsorbents. The results of experiment showed:it was feasible to deal with landfill leachate through this three adsorbent. However, the diatomite is the best.This experiment did research on the effect of adsorbent to landfill leachate, the impact parameters are dosing quantity, water conditions, static sinking time and pH. The conclusion could be obtained as follows:As the concentration of COD is 65000-85000mg/L, ammonia nitrogen's concentration is 1200mg/L in landfill leachate, the optimum reaction condition of diatomite are:pH=7, the amount of dosing is 5g/L, water condition is 250r/min, static sinking time is 20min. Under these reaction conditions, the removing rate of COD is 30.09%, the removing rate of ammonia nitrogen is 29.77%, and the removing rate of SS is 51.68%.As the range of COD in landfill leachate is 59840-67200mg/L, NH3-N is 1340～1680mg/L, the optimum reaction condition for zeolite are:pH=6, the amount of dosing is 15g/L, water condition is 200r/min (3min), static sinking time is 1h. Under these reaction conditions, the removing rates of COD, ammonia nitrogen and SS are 35.29%, is 25.15%, is 55.12%As the concentration of COD is 58779～66738mg/L, ammonia nitrogen's concentration is 1456-1611mg/L in landfill leachate, the optimum reaction condition of kaolin are:pH=7, the amount of dosing is 5g/L, water condition is 300r/min(3min), static sinking time is 15min. Under these reaction conditions, the removing rate of COD is 22.18%, the removing rate of ammonia nitrogen is 17.12%, and the removing rate of SS is 23.87%.According to the test results and mechanism analysis, as to the three kinds of absorbents, the mainly reaction of pollutants in landfill leachate are physical adsorption and chemical adsorption. The mainly characteristic of diatomite are light, high porosity and large pore range; zeolite is framework structure of porous aqueous aluminum silicate crystals, with strong ion exchange capacity to treatment ammonia nitrogen; the advantages of kaolin are the unique layered-structure and large specific surface area.