BIORREATOR A MEMBRANA DE LEITO MÓVEL SEGUIDO DE OZONIZAÇÃO NA REMOÇÃO DE MATÉRIA ORGÂNICA E NUTRIENTES DE EFLUENTE DE INDÚSTRIA DE PAPEL TISSUE

Abstract

The problem associated with the high generation of industrial effluents and their potential impacts in terms of environmental pollution makes special attention focused on the most efficient technological alternatives for the treatment of wastewater. Membrane bioreactor (BRM) technology has been investigated in recent years in the treatment of effluents, due to the excellent performance in pollutant removal, especially when used in the treatment of paper effluent. Such technology, allows the degradation of carbonaceous organic matter and nutrients, contained in effluents, from the conjunction of the biological and physical stages, represented in the latter case, by the separation by membranes. In the present study, the BRM was allied to the post-treatment stage with ozone, with the propose to promote the additional removal of specific organic compounds such as effluent discoloration and the possible removal of total phenolic compounds. In this context, the present study aimed to analyze the efficiency of removal of organic matter, nutrients (N and P), color and total phenolic compounds present in the paper effluent samples, through the use of moving bed membrane bioreactor operated in sequencing batch mode (MBRSB-MB), under different membrane-specific aerated demands, and application of post-treatment by ozonation. The research was divided into three stages, including: Step 1) strategy comprised an aeration demand of 0,32 m3 m-2 h-1 in an operational cycle of 8 hours and sludge age of 15 days; Step 2) strategy keeping the operating cycle and age of the sludge, varying the aeration demand to 0,16 m3 m-2 h-1 and Step 3) post-treatment of the permeate from the previous strategy (Step 2) with ozone under different concentrations applied and contact times of 5, 10, 15 and 300 seconds. It was found that, with the first strategy the performance of reactor in the removal of the parameters organic matter, ammoniacal nitrogen, total phenolic compounds, turbidity and color in comparison with the second strategy. The use of ozonation represented an improvement in the overall efficiency of the process in terms of true color removal (about 90%) within a five-minute contact time. From the results obtained, it was concluded that the use of the system composed of a bioreactor the mobile bed membrane, is efficient in the treatment of effluent from the paper tissue industry due to the removal of chemical demand of oxygen and nutrients (N and P). The use of ozonation as post-treatment showed good results in the removal of total phenolic compounds and in the discoloration of the effluent, however, the efficiencies obtained for such parameters were often not sufficient to comply with the release standards imposed by the relevant environmental legislation, needing expand the study under different times of application and O3 concentrations in the studied effluent.