EVALUATION OF URBAN WASTES FOR AGRICULTURAL USE

Three different groups of municipal wastes: The organic fraction of mu nicipal solid wastes, sewage sludges, and composts of these materials were characterized in order to evaluate their suitability as fertilize rs. The parameters determined were: pH, contents of N, P, K, total org anic C, water-soluble C, extractable C, pH 2-soluble C, pH 2-precipita ted C, heavy metals, and organic phytotoxic substances as well as micr obiological activity (respiration). The physiological effect of these wastes on seed germination was also studied. Sewage sludges showed the highest N and P contents while NO3- content was higher in composts. T he fresh wastes exhibited a higher organic matter content than compost s but the organic matter of the latter was most stable and humified. A queous extracts of the fresh products (municipal solid wastes and sewa ge sludges) inhibited the germination of Lepidium sativum seeds.