Avaliação do desempenho de um biorreator com membranas aeróbio com adição de carvão ativado em pó no tratamento de vinhoto

Abstract

The sugarcane sector in Brazil has a great social, economic and environmental importance. It creates jobs contributies to GDP and produces a renewable fuel. However, the alcohol production demands high volume of water and generates high volume of effluent, as well. An important effluent, the vinasse, has a high organic and nutrient load which justify the need for an efficient treatment process. In this context, membrane bioreactors (MBR) can be consider an adequate technology for the treatment of vinasse because they operate with high concentrations of biomass, small hydraulic retention times and produce high quality treated effluent that may meet the standards reuse in industry. The aim of this study was to evaluate treatment efficiency of vinasse an using ultrafiltration system followed by aerobic MBR operating without and with addition of powdered activated carbon (PAC).The PAC was added to the MBR to improve the characteristics of the treated effluent and to minimize fouling membrane, the major problem during operation MBR. The present study was divided into five phases: in the first stage it was carried out the physicochemical characterization of raw vinasse, in the second phase the raw vinasse passed through the ultrafiltration system to reduce the organic load, the third phase BRM operated without the addition of PAC, in the fourth phase were performed tests with Jar-test using permeate from the previous step with different concentrations of PAC to determining the concentration to be used in the fifth phase, which was MBR operation with addition of PAC. The pre-treatment using ultrafiltration resulted in a removal efficiency of 49%, 96%, 40% and 60% for COD, color, phosphorus and nitrogen, respectively and generate a concentrate with high potential to be used in fertiirrigation. The addition of PAC in MBR improved the removal efficiency of COD, TOC, BOD, color, total nitrogen and phosphorus.The PAC also helped to reduce the concentration of SMP (Soluble Microbial Products) and EPS (Extracellular Polymeric Substances), but caused the breakdown of biological flocs and caused an increase of the total resistance to filtration. The route proposal to that treatment of vinasse showed high efficiency of removal pollutants, enabling the reuse of the effluent on the washing of sugar cane. The addition PAC changed the characteristics of the reaction liquid and did not provide any improvement in the process of fouling membrane.