Investigation on Quality of Leachate from Municipal Solid Waste Landfill and Compost plant (Case Study: Mashhad city)

The leachate quality of Mashhad landfill and receiving and fermentation units of its composting plant was studied. Samples were taken during spring and summer, 2006. BOD, COD, TDS, TSS, NO3-N¯, NH4-N+, PO4 3-, Cl¯, pH, as well 10heavy metals Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn analysis in the samples. Mean COD, NO3¯N¯, and NH4-N+ in landfill, receiving and fermentation units samples were obtained 17418, 50512, 91168 mg COD/l and 2.34, 25.40, 25.97 mg NO3-N¯/l, and 658.78, 570.89, 633.89 mg NH4-N+/l, respectively. The quality of leachate samples compared with Leachate of Tehran landfill and landfills in USA, Germany, Spain, Taiwan, Hong Kong, and Kuwait. The results showed the leachate of Tehran and Mashhad landfills and the composting plant have more organic materials than the other countries. BOD5/COD that shows biodegradability of organic matters was 0.44, 0.51, and 0.55 in the leachate of landfill, receiving and fermentation units, respectively. It means biological treatment can be useful for all of them. Heavy metals concentrations were under national effluent standard in the landfill leachate. But the concentration of Fe, Zn and Mn were above the standard in the leachate of receiving and fermentation units. The results showed that it is possible to meet the national standard by using a combination of physical- chemical and biological treatment methods.