An Indicator to Evaluate the Environmental Impact of Oil Waste Water’s Sheddding on Cultivated Fields

Several climatic, soil and topographic factors need to be considered when evaluating the impact of human actions on the environment. Such variables may be related in a complex way to environmental impact, thus making its evaluation difficult. Problems of this type emerge when evaluating the risks olive oil waste water pose to the environment when shed on cultivated soils. This paper proposes a fuzzy expert system to calculate a modular indicator, ICARO, which allows an evaluation of the potential environmental impact of the application of olive oil waste water in a field. Five modules were formulated, one (“Waste water”) reflecting the nature of the waste water, two (“Groundwater”, “Surface water”) reflecting the risk for the most sensitive agro-environmental compartments (groundwater, surface water), one (“Crop”) reflecting possible consequences on the cropping system adopted, and one (“Soil”) reflecting the soil aptitude to receive waste waters.The input variables are therefore waste water amount and properties, site-specific conditions, and characteristics of the application considered. For each input variable, two functions describing membership to the fuzzy subsets Favorable (F) and Unfavorable (U) have been defined. The expert system calculates the value of each module according to both the degree of membership of the input variables to the subsets F and U, and a set of decision rules. The five modules can be considered individually or can be aggregated (again according to level of membership to fuzzy subsets F and U and a set of decision rules) into the synthetic indicator ICARO. Outcomes of a sensitivity analysis are presented. The system is flexible and can be used as a decision aid tool to authorize waste water’s shedding or subordinate the distribution on fields to acceptance of some limitations (amount, timing, site, etc).