Estudo das potencialidades do uso dos coagulantes naturais no tratamento das águas do rio Infulene

Abstract

Water intended for human consumption must meet minimum conditions in order to be able to be ingested or used for hygienic purposes. Most rural communities, for example, consume low quality water, are permanently at risk of infections and diseases of great gravity. Aluminum sulfate has been the most used coagulant due to its good performance. However, this coagulant has some disadvantages, such as dependence on pH, and generates waste with a high concentration of aluminum, making it difficult to use this residue. The treatment of water with natural coagulants does not pose any health risks and its application is greatly simplified, since the natural chemical substance will have a greater chance of a physical-chemical reaction. chemistry with the colloidal material that gives turbidity to the water. In this work, the use of comparison of crushed seeds of M. Oleífera and manioc flour (natural coagulants) for the treatment of the waters of the Infulene River in rainy weather. This report is the product of a three-month Labor Internship, enriched with professional experience in the Engineering Laboratory of Mozambique (LEM) and conducting laboratory tests, linked to the subject under study. Samples were collected at three points in the river (1 at Pontinha- ​​Wastewater Treatment Station, 2 at CDM, 3 at Lusovinhos), at January 2013. For the study, the parameters were determined: pH, TDS, CE, turbidity and NH 4+ measured with portable devices immediately after sampling; Cl - by volume; SO 42- by gravimetry; Ca 2+, Mg 2+, Cu 2+, Fe 2+ and Zn 2+ by atomic absorption spectrophotometry with flame atomization (FAAS); Na + and K + by flame photometry (FC) and fecal coliforms and totals by the filter membrane method. The study results show that flour Cassava can serve as a natural coagulant (there has been a decrease in turbidity in all water samples, ammonium ion elimination and coliforms). At work, the comparison of the efficiency of the coagulant properties of moringa and cassava in relation to the aluminum sulphate in the water treatment of the Infulene River where wastewater is stripped which comes from the operation of the Maputo beer and wine factories. According to Statistical calculations state with 95% confidence that there is a significant difference between the two natural coagulants, in their effect on Cu 2+, Zn 2+ and Na +. Regarding aluminum sulfate, no significant difference was detected for the physical-chemical parameters, TDS, CE, turbidity eNH 4+. The presentation of local means for water treatment aims to contribute to the implementation and dissemination of these techniques for the improvement of water quality, allowing the best use of this resource.