Sizing a leachate treatment station (Cameroon)

The objective of this work is to protect the environment from leachate produced at the Mbanga Ebolowa landfill. This study involves determining the quantity of leachate produced in the Ebolowa waste treatment centre, determining the chemical, physical, physicochemical and biological composition of the leachate, and ultimately making a treatment proposal. The average daily volume of leachate produced at the landfill is quite significant due to the organic matter content of the waste, the high monthly temperatures and the high frequency of sizing a wastewater treatment plant at suitable for the treatment of rainfall leachate (250 to 242 mm for the high monthly frequencies October and April, respectively). Laboratory analysis of leachate from leachate storage wells at the landfill shows that this wastewater is very loaded with organic matter and this results in the very high presence of MES (1,719 mg/l), COD (3,408 mg/l) and BOD5 (1,227 mg/l). It is also important to note that the COD/BOD5 ratio which is 2.8 allowed us to determine that the leachate from this landfill should have partial biological treatment. The biological treatment chosen for the treatment of leachate is a vertical flow planted filter system. The volume of the storage basin which acts as a retention basin is 3,160 m3, the vertical flow planted filter basin has a volume of 405 m3 with a retention time of 15 hours. The purification performances lead to physicochemical parameters of the order of 80 mg/l for SS, 879 mg/l for COD and 196 mg/l for BOD5 although these do not reach not the discharge standards. To complete the treatment of leachate before its discharge; it is recommended to do a second treatment by adsorption with activated carbon.