Valorisation of a wastewater in the treatment of leachate from municipal solid waste in Morocco

Abstract

In most countries, sanitary landfilling is the common way to dispose municipal solid wastes. In general, leachate treatment is a difficult and expensive process. Although; leachate can be treated by biological processes, chemical oxygen demand removal efficiency is usually low due to high ammonium ion content and the presence of toxic compounds such as metal ions. This experimental study was conducted to investigate the effect of coagulation-flocculation process on the fresh leachate resulting from compacting of solid waste of Mohammedia city. The effects of steel industry wastewater (SIWW) rich in Fe3+ and commercial coagulant ferric chloride of 40% with various dosages and also coagulation pH on the removal of turbidity, colour, chemical oxygen demand (COD), biological oxygen demand (BOD5) and total suspended solids were studied. Based on the results of this study, the best coagulant for colour and turbidity removal was SIWW. An equivalent of 7,080 mg.L−1 of FeCl3 was needed to effectively remove 63% of turbidity. This liquid waste can remove 44.5% of COD at the concentration equal to 1,000 mg.L−1 of FeCl3. The physico-chemical process may be used as an effective pre-treatment process, especially for fresh leachate, prior to post-treatment (polishing) for partially stabilised leachate.