Design and development of bio-reactors and leachate barricades for landfill leachate treatment

Abstract

The treatment of leachate from open dump sites/landfills is a challenging task due to its complexity and high pollutant loads. In recent years, new technologies have been developed on leachate treatment however, most of them are expensive and complex to conduct. Anaerobic ammonium oxidation of nitrite to N2(ANAMMOX) has gained recent attention to treat high ammonia wastewaters. At the same time, Biochar (BC) pyrolyzed by the biowaste of municipal solid waste (MSW) has shown a promising capacity in removing nutrients, heavy metals, total solids and organics including volatile organic compouds (VOCs) in landfill leachate.Hence, the objectives of the study are to treat nitrogen rich leachate through anammox and biochar barricades followed by a biochar embeddedsubsurface constructionwetland. Characterization of landfill leachate was done for the leachate from the Karadiyana dump site for various parameters indicated that the leachate was highly contaminated from solids both total and volatiles (6000-25000 mg/L), low nitrate however with high ammonia-N (900 mg/L), high Chemical Oxygen Demand (COD) (6000 to 20000 mg/L) and high heavy metals/metalloids such as Zn, As etc. Initially anammox bacteria were incubated in laboratory scale. Biochar production was taken place at the dump site using the barrel method for the residue from composting by slow pyrolyzing process.The discharge of leachate was measured using a v-notch.The pre-filter columnshaving both wood biochar and MSW biochar were strong enough to remove COD considerably and ammonia, nitrate and EC at initial stage. However, the removal efficiency continues to drop over the time. The pre-treatment unit showed a potential removal of contaminants from leachate and based on that designs were done for the pilot scale treatment train for the site.