Study On Treating Landfill Leachate With The Biological Diatomaceous Earth Craft And The Electrolytic Process

Considering the difficult problem of the treatment of the refractory organic compound and high concentration ammonia in landfill leachate, Bio-diatomite Process and Electrolytic Oxidation Process for Leachate were studied in this paper. When two diatomite reactors were in series to treat effluent of the biological treatment system for landfill leachate in mature landfill, the removal efficiency of COD was above 50% and the removal efficiency of color was above 70%. In the Bio-diatomite Process, the diatomite was used as the carrier of microorganism, thus the concentration of activated sludge was enhanced and the sludge loading was reduced. Therefore the removal efficiencies of COD and Ammonia were high and the process could endure the transformation of load. The results showed that adding lime to the Leachate, the removal efficiency of Ammonia was above 94% and the concentration of Ammonia in the effluent of the Bio-diatomite Process was below 15mg/L. The Electrolytic Oxidation Process could be used to remove the COD and Ammonia in the effluent of the biological treatment system. The main affecting factors involved the influent concentration of COD and Ammonia, current density, the ratio of electrode area to flowrate, electrolysis time, etc.. Enhancing current density, electrolysis time and concentration of chloric were better for electrolysis efficiency. When RuO₂-IrO₂-TiO₂/Ti was used as electrode, electrode gap was 10 mm and the influent concentration of COD and Ammonia were about 500mg/L and 15mg/L respectively, the best current density was around 2.8A/dm². In order to achieve the second Discharge Standard, the electrolysis time was only about 15 minutes and the energy consume was about 5.7～6.8kWh/t. In order to achieve the second Discharge Standard, the electrolysis time was only about 82 minutes and the energy consume was about 34.5～37.3kWh/t. Furthermore, the character of diatomite, the mechanism and affecting factors of Bio-diatomite Process and Electrolytic Oxidation Process were also discussed in this paper. Finally, the paper was summarized and some advice were proposed.