START-UP OF AN ANAEROBIC HORIZONTAL-FLOW REACTOR FOR TREATING WASTEWATER FROM A COFFEE FRUITS PROCESSING

This study aimed to evaluate the start-up and the adaptation of an anaerobic horizontal-flow immobilized biomass (HAIB) reactor in order to treat wastewater from a primary processing of coffee fruits. The reactor was built with PVC tubes of 0.2 m in diameter and 3.2 m in length. The system was filled with cubes of polyurethane foam for immobilization of active biomass. The reactor presented a total capacity of 0.1 m(3) and reaction volume equal to 0.04 m(3). 49% of organic matter. Removal efficiency was observed, with medium organic volumetric loads equal to 2.66 kg m(-3) d(-1) (as chemical oxygen demand). The supplementary addition of alkalinity and the previous biomass inoculation provided a stable start-up of the reactor, as confirmed by the reduction of volatile acids and an adaptation of the present microbiology community. The systems showed resistance to changes in flow and in the organic load observed; the levels of phenol and potassium monitored did not cause inhibition of the biological activity. A better control on the changes in load rates is an important topic for the next studies.