Anaerobic Digestion of Olive Oil Mill Effluent Pretreated and Stored in Municipal Solid Waste Sanitary Landfills

Abstract

Sanitary landfills of municipal solid waste (MSW) might be used to reduce the storage volume required at plants giving year-round treatment of olive oil mill effluent (OME). A landfill in the methanogenic stage could act as an anaerobic filter and reduce the pollutional load of the OME while also acting as a temporary storage tank. In the present work, a lysimeter in pilot scale was used to simulate a cell of a sanitary landfill. It was filled with MSW screened by a 80 mm mesh sieve mixed to municipal sludge. Results show that when OME was spread on the top of the lysimeter at a loading rate not exceeding 0.4 kgCOD/d/m³ of reactor steady methanogenic activity was maintained in the layers of refuse and a 70% removal of COD was obtained in the OME leachate collected. Higher loading rates reduced methanogenic activity and COD removal efficiency. Nevertheless, the OME collected from the bottom of the landfill was more easily treated by anaerobic digestion than was the raw OME.