Avaliação do tratamento de lixiviado de aterro sanitário através de processo oxidativo avançado conjugado com sistema de separação por membranas

Abstract

The landfill leachate is characterized by high recalcitrant organic matter concentration, ammonia and toxic compounds. This effluent can be an environmental problem due to its high pollutant potential when it is released without treatment. Studies reported in the literature showed that biological processes are not sufficient in meeting the discharge standards in force. An attractive alternative for this type of leachate are advanced oxidation processes (AOP). AOP is defined as a process that involves the generation of hydroxyl radicals, highly reactive, which have high capacity for destruction of organic pollutants. However, whenapplied in isolation, does not permit the framing of the effluent and has to be combined with techniques of post-treatment. The processes of membrane separation (MSP) are variations of conventional filtration processes, where the seletive array are constituted for pores muchlower or dense medium. The combination of the AOP/Fenton with MSP has several advantages and is adequate to treat landfill leachate. This study aimed to assess, in bench scale, the treatability of the leachate from the Belo Horizonte landfill through the AOP/Fenton with in order to framing to the environmental standards. The study involved the characterization of raw leachate as a subsidy for the design and optimization of biological treatment. In the first stage of the research results indicated that the leachate had features of stabilized landfill. It was also noted that the raw leachate has a fraction of inert COD of around 40% and maximum degradation of 46.6% and almost all of the components has low molecular weight (< 5 kDa). The concentration of humic substances was equivalent to 26.9% of total of the COD in periods of hidric defict, with predominance species humic acids. In the second step, the AOP/Fenton, in their optimized conditions, showed high removal efficiency of COD, color and humic substances in all fractions of molecular weight. In the second step, the AOP/Fenton, in their optimized conditions, showed high removal efficiency of COD, color and humic substances in all fractions of molecular weight. In the sludge generated was detected high COD and total carbon concentration, evidencing the adsorption phenomenon during the oxidation reaction. The MSP shown to be technically feasible as a complementary treatment, with average real color rejection of 99.6%, TS of 99.4%, organic matter in terms of COD of 98.4%, TKN of 91.6%, phosphorus total of 100%, alkalinity of 100% and chloride ions present of 83.0%. The conjugation of all steps was sufficient to framing the treated effluent to the environmental standards in all parameters with the exception of nitrogen.