Agricultural use of municipal sludge. Case study of the Metropolitan Area of Curitiba, Brazil.

Abstract

The sanitation company of Paraná‐ Sanepar destinates its sludge, which is produced in sewage treatment plants, to agricultural use, aiming to provide the most correct final disposition in sanitary, environmental and social aspects, improve the soil conditions, increase agricultural productivity and reduce agriculturists’ production costs. This destination is the one which suits better to the concept of integrated sustainable development due to it leads the organical matter back to the soil, avoid contamination issues and hydrical resources degradation, and also contributes to food and fiber production. Sanepar has a very strict control which guarantee the sludge quality for agriculturists, regarding odor, heavy metals contamination and pathologic microorganisms. In 2007, adaptation period to the Conama 375/06 e Sema 001/07 resolutions, the sewage treatment plants of Curitiba Metropolitan Region destinated 8.903 tonnes of sewage sludge ( average humidity 64%) to application to 295 ha of corn, beans and soy crops, green fertilizing, pos‐harvest and implantation of peach orchards. 29 agriculturists were supplied and that generated a R$467,90 per hectare economy, concerning the reduction of chemical fetilizers and calcium carbonate.