Recuperação de nutrientes de esgoto tratado após filtração em membranas

Abstract

Membranes concentrates, obtained from sewage treatment, have potential for use as fertilizer due its concentration of nutrients, as well as contribute to the management of these concentrates. This concentrates may cause serious impacts when disposed improperly in the environment. Agricultural uses the nutrients, mainly Nitrogen and Phosphorus, which are necessary for plant nutrition. In these terms, nanofiltration and reverse osmosis membranes were used to concentrate the sewage nutrients treated biologically through recirculation mode to the feed tank, in order to obtain a concentrate rich in nutrient in order to be compared to a commercial liquid mineral fertilizer. Experiments were performed with and without the concentrate recirculation and collected permeate and concentrated aliquots for physicochemical characterization and flow measurements over time. The results showed that the concentration of the nutrients in membranes concentrates were statistically lower than the minimum standards set for a liquid fertilizer that can be marketed for soil application. Furthermore, the concentration process negatively influenced the flow and quality of the final permeated, although commercial liquid fertilizers are not considered for soil applications, according to the current Instruction Normative, concentrated in membranes can be used as fertilizer for hydroponics or solution for ready use, since is such cases the minimum concentrations requirements depend on the manufacturer.