Evaluation of landfill leachate pollution and treatment

Leachate from municipalities’ landfills represents a potential health risk to both surrounding ecosystems and human populations. This study deals with the Ouled Fayet site (west of Algiers), which has been operational for five years, receiving non-hazardous, municipal and assimilated wastes from 34 municipalities corresponding to 363,000 T/year, stored in a settler and then rejected in the receiving environment. The composition of the wastes is extremely changeable according to the nature, the deposit time, and the climatic changes.Several landfill leachate samples were taken from the entry and exit settler, and evaluated. The analysis yielded the following results; very concentrated organic matter, chemical oxygen demand (COD) = 3552 mg/L, BOD5 = 980mg/L and BOD/COD ratio of 0.25. We observed that the water leachate is in the anaerobic reactions corresponding to the beginning of methane step, the pH of 8.27 reflects this biochemical evolution phase. Management of Algiers is undergoing drastic changes (source separation, closure of old landfills, reduction of the number etc.) that is why the municipalities are actually forced by the legislation to follow a minimization of the solid wastes by adopting a new strategy of reuse and recycling before all elimination or treatment possibility.