Agricultural sewage sludge reuse potential in Apulia (Italy): analysis of different scenarios for the support of legislative decisions

Agricultural use is one of the best options for sewage sludge management, whenever sludge quality is suitable with respect to established law limits and if local situations (field availability, climate, specific constraints) are favourable. This practice is recognized to be the most economical one and allows recovering nutrients and organic matter with benefits to crops and land. Beside general rules issued at European level (Directive 86/278/EEC) and transposed in Italy with D.Lgs. 99/1992, regional authorities can establish other restrictions to better protect environment, preserve population from nuisance and defend specific areas. Through GIS elaborations, we have analysed different scenarios, computing available land in Apulia region with present and new revised constraints and evaluating sludge quantities to be potentially recovered for land application in the light of current legislative limits, nitrogen requirements by crops and cultivation cycles. This study has showed that available land can face the total sludge production in the area even in the most conservative hypothesis. The used methodology represents a powerful tool to move the focus of political decisions from general law constraints towards specific ones closely related to the environmental and agricultural context and to plan new investments to completely satisfy sludge disposal needs.