Avaliação temporal da codigestão anaeróbia de lixiviado de aterro industrial e glicerina em batelada

Abstract

The present study aimed to evaluate the performance of the anaerobic codigestion of the industrial landfill leachate in association with crude residual glycerin from biodiesel production. It was verified the influence of factors such as volume of substrates, food / microorganism ratio and reaction time for codigestion, monitoring through the parameters COD (Chemical Oxygen Demand), alkalinity and total volatile acids. The tests were carried out in batch in reactors with a useful volume of 400 mL, being 100 mL of inoculum, 100 mL of substrate and 200 mL of nutrients. A Rotational Central Compound Design was used, comprising a factorial of type 22, with four tests at levels +1 and -1, four tests at axial point levels (-1.414 and +1.414) and a triplicate at the central point (0), totaling 11 assays. Forty-four reactors were assembled and at each eight-day interval 11 reactors were disassembled, totaling a period of 32 days. After analysis of the parameters, regression coefficients, (ANOVA) and response surface graphs were calculated for the significance level of 90%. With the aid of surface response graphs it was possible to observe that the efficiency of the treatment for COD removal improves according to whether the percentage of glycerin and the food / microorganism ratio is increased, with a combination of 5% glycerin and 1.7 A/M ratio, resulting in removal efficiency of 99.17% COD. The values of alkalinity and total volatile acids showed equilibrium in the reactor and decreased gradually with each monitoring period. It is possible to affirm that the process of codigestión of leached with the glycerine can be considered a possible alternative for the suitable treatment of these substrates.