INVESTIGADORES
AREA Maria Cristina
congresos y reuniones científicas
Título:
Treatment of liquid waste streams from a chemical process applied to forest biomass
Autor/es:
COVINICH, L.G.; FENOGLIO, R.J.; FELISSIA, F. E.; AREA M.C.
Lugar:
Montevideo
Reunión:
Workshop; I&S WORKSHOP. Insights and strategies towards a bio-based economy; 2016
Institución organizadora:
Universidad de la República; I+D+i . Technological Laboratory of Uruguay (LATU); Instituto Nacional de Investigación Agropecuaria (INIA). Uruguay - VTT - Technical Research Centre of Finland; Faculty of Chemistry and Engineering. Åbo Akademi University. F
Resumen:
The biorefinery concept involves an integral approach in the use of lignocellulosic materials. This is achieved by different fractionation processes that allow producing high added value products. Following the application of these processes, waste liquid streams containing various aromatic compounds of recalcitrant nature are generated. Therefore, the manufacturing processes needs to become more efficient, both in terms of resources use and in terms of waste reduction. Advanced Oxidation Processes (AOP) exploit the high oxidation potential of hydroxyl radicals, which attacks most of organic molecules. The high reactivity of these radicals and their low selectivity during the oxidation process are useful attributes. The utilization of H2O2 has emerged as a viable alternative among other oxidants, because it improves the efficiency of the oxidation, it is non-toxic, and does not form any harmful by-products. One of the main drawbacks of the heterogeneous catalytic systems corresponds to the leaching of the active phase from the catalytic support, which can react with H2O2 in homogeneous phase. The objective of this study was to optimize the oxidative reaction of a liquid waste from a soda-sulfite treatment of wood (a mixture of willows, poplar and eucalyptus, and old newspaper) through an experimental design to achieve the lowest total organic carbon (TOC), chemical oxygen demand (COD), aromaticity, and leachate after the reaction. The required removal amount depends on the chemical characteristics of wastewater, including the specific SUVA254. This parameter is defined as the UV absorbance at 254 nanometers measured in inverse meters (m-1) divided by the total organic carbon concentration measured in milligrams per liter (mg/L). SUVA254, the ?average? absorptivity for all the molecules of aromatic characteristics, was used as a measurement of the samples aromaticity (L/ mg m). The analyzed factors were: temperature of the reaction (°C), content of supported copper (mg/L), and initial dose of H2O2 (g/L). The optimum conditions were: 80ºC, 65 mg/L of supported cooper, and 3.23 g/L of H2O2. Optimum achieved results were: 51, 56, and 92% reductions of TOC, COD, and aromaticity, respectively, and only 1.3% of leached copper. Additionally, toxicity measurements of the treated and untreated liquid streams were performed by the oxygen consumption rate (R in mgO2/L h) as an indicator of the activity of aerobic microorganisms. Exposure of biomass to the alkaline sulfite liquor produced no decrease in R (barely 0.01% of reduction), indicating the negligible toxicity of alkaline sulphite liquor and its degradation products.