Reúso da areia do desarenador de Estação de Tratamento de Esgoto (ETE) na fabricação de concreto

Abstract

Effluents represent evictions from the different modalities of water use and generate pollution when disposed of no treatment in the environment. Thus, it is necessary to perform treatment that meets the standards of release, as well as the steps necessary for the process. Sewage treatment is classified as preliminary, primary, secondary and tertiary. Being the preliminary treatment the retention of the coarse solids present in the effluent, such as sand and organic matter and must be present in all Sewer Treatment Station (STP) (ETE). Therefore, the present paper has as general objective to evaluate the reuse of the sand coming from the Sewage Treatment Station desander in the manufacture of concrete. The specific objectives were: characterize the physical-chemical and bacteriological aspects of sand; characterize the sand in its geotechnical aspects; perform tests of technological control of the concrete produce 7 with the sand. The molding of the specimens was performed according to NBR 5738:2003. The sand disinfection process was performed with solution chlorine. Microbiological analysis (Colilert test) indicated absence of thermotolerant coliforms and presence of total coliforms. The results found in the physical-chemical analyzes of the crude sample indicated high moisture content Chemical Oxygen Demand (QOD) of 1351 mg/kg due to the high concentration of organic matter, however calcination process was used to remove the total volatile solids, the pH analysis indicated acidity condition. The use of 50% of sand of Sewer Treatment Station (STP) (ETE), in the confection of concrete was satisfactory when compared to conventional concrete. The compressive strength tests performed after 7, 14, 21 and 28 days indicated resistance (MPa) of 22.9, 23.8, 27.1 and 27.8, respectively.