Influencia da redução da espessura da camada suporte na eficiencia da filtração lenta com uso de mantas sinteticas não tecidas para aguas de abastecimento




The purpose of this study was to investigate the influence of the gravel suporter bed replacement for nonwoven synthetic fabrics in slow sand filtration for treating water supplies. The experimental investigation was carried out in a pilot plant built with an upflow roughing filter unit and three slow sand filtration units, which were made by sand (Te = 0,25mm, CO = 2.4 and grain size varying between 0,053m and 0,85mm and nonwoven synthetic fabrics (M2: mass per unit area = 380 g/m2, M3: mass per unit area = 450 g/m2 and thickness = 8 mm) installed on the sand layer top. The three units of slow sand filtration (FL 1, FL2, FL3) were different considering the thickness and composition of the gravel suporter bed. The first unit, FL 1 has gravel size varying between 2.00 mm to 6,25 mm, the second unit, FL2, has gravel size varying between 6,25 mm to 21,0 mm plus nonwoven synthetic fabric (M1: mass per unit area = 300 g/m2, thickness = 2 mm) and the third unit, FL3, has only fabric (M1: mass per unit area = 300 g/m2, thickness = 2 mm). The filtration rates used in the essays were 3m3/m2day, 6m3/m2day e 9m3/m2day. The slow sand filtration units efficiency was evaluated by measurement of the main water quality parameters: turbidity, apparent color, total coliforms, fecal coliforms, iron, manganese, dissolved oxygen, total suspended solids and pH. The results showed that the efficiency of impurities removal did not have significant difference between the three slow sand filters, indicating that the substitution of the gravel by nonwoven synthetic fabric (M1: mass per unit area = 300 g/m, thickness = 2 mm) viability in the suporter bed for slow sand filtration. This makes possible to extend the filtration run duration and also to reduct the technology implantation costs, making it accessible to developing countries and regions


comunidades agricolas geotexteis filtros e filtração abastecimento de agua

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