Adición de zeolita en reactor EGSB para el tratamiento de aguas residuales porcinas

The effect of zeolite addition in an expanded granular sludge bed anaerobic reactor (EGSB) for the treatment of swine wastewater at high organic loading rates (OLR) was evaluated. The results showed that the presence of the zeolite did not affect the hydrodynamics of the EGSB, adjusting the model of tanks in series. Two reactors (R1 and R2) were operated with effective volume of 3.04 L at 30 ᶱ C. Reactor 1 was operated only with granular sludge while 120 g of zeolite (5 cm of static bed) were added in R2. Theoretical hydraulic retention time (HRT) was 12 hours, obtained with an influent flow rate of 4.0 mL/min. Firstly; an organic load shock (OLS) strategy with constant up-flow velocity (v up ) of 6 m/h for 180 days was evaluated. The evolution of pH, Total Kjeldahl Nitrogen (TKN), Chemical Oxygen Demand (COD) and volatile fatty acids (VFAs) was monitored during the anaerobic digestion process with OSL and the increase of the organic loading rate (OLR). In addition, the microbial composition and the changes in bacterial and archaeal community structures were assessed. The reactor with zeolite addition showed a higher stability at high OLR reaching efficiency of 80% at 32 kgDQO/m 3 d. Subsequently, gradual increase of both OLR and the up-flow velocity to 10 m/h for a period of 255 days was evaluated. In this study, a trend never before reported was observed, increasing its efficiency to 90% and achieving a higher rate of organic degradation. It can be ensured that the addition of 40 g/L zeolite to the EGSB allowed the higher stability of the system with robustness when varying the operational conditions. Moreover, changes in microbial diversity were observed.