Estudo da retenção de matéria orgânica e da taxa de infiltração de esgoto tratado lançado em solo arenoso recoberto com geotêxteis nãotecidos

Abstract

In Brazil is very common to use decentralized systems as sewage treatment option, for they are simple to construct, they have low implantation costs and basic sanitation systems are still in slow progress. However, those decentralized systems are polluting soil and groundwater sources and recovering these areas can be very expensive and even inefficient. With that in mind, using geotextiles comes up as an alternative for soil preservation and for maintaining its capacity of infiltration, because part of clogging will happen in the geotextile. Furthermore, its utilization does not affect the system operation and with the possibility of swapping the geotextile when it clogs. This study has as objective to evaluate the retention of organic matter in a non-woven geotextile as also the infiltration rate of the system. For this, were build three infiltration columns in triplicate, with the following configuration: filter + sand covered with 130 g/m² geotextile, filter + sand covered with 300 g/m² geotextile and filter + sand without geotextile, fed with the effluent of a treatment system consisting of a septic tank followed by anaerobic filter. The systems were continuously fed in a way that it was always maintained constant hydraulic load of 10cm above the percolation columns, inducing them to anaerobic conditions. The experiment was operated for 87 days; however, at the 38th day, the geotextiles of two columns of each triplicate were replaced, because the amount of effluent was not enough for analysis. At the 38th and 52th day, the soil used to fill the percolation columns was analyzed to obtain the organic matter content. Meanwhile, the infiltration rate was measured during the whole study.