Agronomical use of sewage sludge from Urban Waste Water Treatment : heavy metals in Zea Mais

The Urban Waste Water Treatment Directive (91/271/EEC) aims to encourage the use of sludge whenever appropriate ; the Sewage sludge is a product of wastewater treatment which could find a reutilisation in the agricultural field. The necessity to find a solution to the sewage and biomass disposal has lead to the development of techniques based on natural reuse of agricultural soils. In this way it represents, through a closed loop system, a source of all the nutritional elements which has been remove by the agriculture. The sewage sludge application on soils represents an alternative to the traditional stock strategies ; more convenient, from the economical point of view, than incineration or disposal in landfill, it also contributes to solve the sewage sludge recycling issue. The aim of this project is to grow up maize under experimental conditions, in order to evaluate the nutrients contribution of the sewage sludge on the final production, while observing the connection between application of sewage sludge and residual heavy metals concentration in the different plant parts.