Avaliação do desempenho de filtros orgânicos no tratamento de água residuária da bovinocultura leiteira

Abstract

Dairy farming stands out as an activity that generates a large amount of wastewater, especially when the management system adopted is the confined. These wastewater have a large amount of nutrients and organic matter, contributing to the eutrophication of groundwater. Filtration is among the alternative forms of primary treatment of bovine livestock wastewater under organic production system (ARB). The objective of this work is to evaluate the performance of organic filters, consisting of wood sawdust, sugarcane bagasse and corn cob, in the primary treatment (filtration) of the wastewater of dairy cattle. The filtration columns consisted of three PET bottles, cut and sealed. The material was conditioned in the columns in layers of 5 cm thick, under compression of 16.7 KN m-2, until all the material was filled (total of 400 g of material per filter). The experimental design was entirely randomized. The chemical and physical characteristics of the ARB before (tributary) and after the filtration process (effluent) were evaluated. The analysis of total solids (ST), volatile solids (SV), turbidity, color, hydrogen ionic potential (pH), electrical conductivity (EC), metals (Ca, Mg, Na, K, Cu, Zn, Mn, Fe And Al) and total nitrogen. As main results it was observed that wood sawdust presented higher efficiency in the reduction of ST, SV and total sodium. This treatment also increased the Zn, Ca and Mg contents in the ARB effluent. The filter consisting of corncobs reduced the turbidity of ARB. It also kept ARB pH close to neutral and indicated for most cultures (pH = 6.5). This material increased the total N and K contents and was the one that showed the lowest total Fe reduction. The sugarcane bagasse reduced the apparent color, electrical conductivity and ARB aluminum content. This material also provided an increase in the Cu and Mn micronutrients.