Efecto del oxígeno y la glucosa en la metanogénesis y mineralización de resinas poliméricas

Abstract

The effect to dissolved oxygen concentration and glucose on the methanogenesis and mineralization of the polymeric resin compounds were examined in batch cultures. They were inoculated with sludge from an upflow anaerobic sludge blanket reactor fed with polymeric resin compounds and 1.0 mg dissolved oxygen L-1, in the steady state. All tests were performed with 1500 mg L-1 of chemical oxygen demand, 30±2 ºC, with 23.8 g L-1 of volatile suspended solids as inoculum and chemical oxygen demand/volatile suspended solids ratio of 1. The effect of different dissolved oxygen concentrations showed evidence that with low concentrations (0.6 and 1.0 mg L-1), the chemical oxygen demand removal efficiency of the glucose and the methanogenic activity remained constants, but the chemical oxygen demand removal efficiency of the polymeric resin compounds increased 58.1±1% and the methane yield decreased, due to the higher aerobic mineralization of the carbon to carbon dioxide. The results of different glucose/polymeric resin compounds ratios in the presence of 0.6 mg L-1 of dissolved oxygen showed that the glucose did not improve the polymeric resin compounds removal. However, the methanogenic activity decreased by 75% with polymeric resin compounds as substrate compared with the methanogenic activity with glucose as the sole carbon source, suggesting that the glucose presence promotes the conditions for higher tolerance to oxygen. Therefore, the presence of low concentrations of dissolved oxygen promotes the methanogenesis and mineralization of polymeric resin compounds.