Estudo das micropropriedades de resíduos sólidos gerados nos decantadores de estações de tratamento de água

Abstract

The conventional or life-cycle system for water treatment (chemical coagulation, flocculation, sedimentation, filtration, disinfection, fluoridation and pH correction) employed in most water treatment plants (WTP) in Brazil turns water unfit for human consumption (spring water and surface water) into a product that is in accordance with the drinking water guidelines for distribution to the population. In this system, the waste generated in the decanters by the addition of chemical coagulants has been termed WTP sludge . This material consists of solid phase and liquid phase (this latter divided into distinct fractions), and free water may represent a considerable portion of it, depending on the cleaning of the sedimentation tanks. The natural removal of free water from WTPs can be performed by natural systems to reduce volume, in which task the drainage beds play a key role. This work studied the microcomponents of solid waste generated in the WTP decanters of 03 cities in the state of Sao Paulo which use distinct types of chemical coagulants. The samples passed through a drying process and subsequent laboratory analysis. In light of the results, suitable strategies for either disposal or reuse of the waste were considered. It was concluded that sludge from sources 1 and 3 have potential for reuse in ceramics, because they have high contents of Al and Si. On the other hand, sludge 2 may be used in red ceramics (due to the high percentage of Iron).