Caracterização e uso do biocarvão de bagaço de malte visando o tratamento de esgoto sanitário

Abstract

The brewing industry generates a lot of solid waste during the process. Much of this residue (malt bagasse) is used in animal feed or fertilization in fields. However, many breweries do not reuse it. Industries try to keep waste minimization costs as low as possible, while relevant legislation remains restrictive. In this sense, the study aimed to evaluate the efficiency of biochars produced from malt bagasse in the treatment of sanitary sewage. Malt bagasse was chemically characterized. Two pretreatments were used in the samples of malt bagasse before the production of the biochars, in addition to the control: (i) washing the malt bagasse with cold water and (ii) washing the malt bagasse with hot water, both with the same volume of water. The treated and untreated samples, with a particle size between 40 and 60 mesh, were pyrolyzed at temperatures of 350 and 500 ° C, with a heating rate of 10 ° C min-1, for 2 hours. Biochars were characterized in terms of immediate chemical analysis, CHNS-O, TG, FTIR and estimated surface area calculation. To perform the treatment of the effluent by adsorption, the six biochars prepared were used. Thus, a factorial design 22 was carried out. The levels of the variables under study in this planning were: mass (0.3 and 0.9 g) and agitation (200 and 300 rpm). The response variable analyzed was the removal efficiency of Total Organic Carbon (TOC). Malt bagasse has desirable characteristics for a precursor material, such as high fixed carbon content (≈ 20%) and high extractive content (≈29%). The pre-treatments for washing the material in cold water and in hot water did not influence the properties of the biochars. The best adsorption conditions in malt bagasse biochar resulted in a removal of approximately 38% of TOC with the 500-S (500 oC/not washed) and 350-Q (350oC/washed with hot water) biochars. This number represents an indication of the applicability of malt bagasse biochars in the removal of organic matter.