The Effect of leachate recirculation on aerobic and anaaerobic degradation of municipal solid waste in landfills

In this study, leachate recirculation and aerobic landfilling of solid wastes are investigated asalternative methods for enhancing solid waste stabilization in landfills that are subjected toseveral research studies for acceleration of solid waste decomposition in recent years. Fourlandfill reactors with inner diameter of 50 cm and height of 200 cm were used to determineaerobic (A-1 and A-2) and anaerobic (AN-1 and AN-2) decomposition of solid wastes. One ofthe reactors used as control (A-2 and AN-2) and one used with leachate recirculation (A-1 andAN-1) for each landfilling operation. Thus, the effect of leachate recirculation is alsodetermined for aerobic and anaerobic landfilling alternatives. The results obtained during 250days for aerobic and 470 days for anaerobic landfill reactors are given.The quality of the leachate is observed by the means of pH, conductivity, alkalinity, totaldissolved solids, oxidation-reduction potential, COD, BOD, chloride, sulphate, total Kjeldahlnitrogen, ammonia, nitrate, and COD fractions in addition to the leachate quantity. Also,heavy metal (Cu, Zn, Cd, Cr, Ni, Pb) and Fe, Ca, K, and Na content of the leachate wereinvestigated during the study.Furthormore, elemental analysis, pH, moisture content, total organic carbon, total Kjeldahlnitrogen, C/N ratio, volatile solids, stability index, and biochemical methane potential of thesolid waste samples taken at the beginning and every 3 months after landfilling of the wastes.Landfill gas composition of the anaerobic landfill reactors and the temperature distributionwithin the landfill body were also investigated during the study.Key Words: Solid waste, Landfilling, Aerobic landfill, Anaerobic landfill, Leachaterecirculation, Leachate.