Disposal site choice for olive mill wastewater

Olive mill wastewater (OMW) is the most significant source of environmental pollution in Sfax, the main olive oil producing region of Tunisia. The management of OMW presents enormous problems due to the great quantities produced annually, its high organic content and toxicity. Storage of OMW in evaporation ponds has been used as a solution, but these ponds induce soil and groundwater contamination. This paper reports on an optimal approach to environmental management of OMW to selected disposal sites in the Agareb region of Sfax. The approach is based on the use of a geographic information system (GIS) and multi-criteria analysis. The GIS manages information describing the study area and offers spatial analysis operators for different environmental, social and economical factors. These multiple layers of information can be integrated in different combinations. Multi-criteria analysis methods are used to determine possible locations for OMW disposal sites (using an analytical hierarchy process) and eventually to select the best options.