SUMMARY
In the community of Pulinguí belonging to the parish of San Andrés del canton Guano province of Chimborazo-Ecuador, domestic sewage is treated in a system of septic tanks and upward filter, which presents problems of badsmell and low reduction of organic matter. The objective of the present work was to evaluate at laboratory scale theefficiency of pollutant removal by combining the current anaerobic treatment with an aerobic treatment by activatedsludge. A prototype with 27.9 liters capacity was designed, built and operated, of which 15.8 liters correspond tothe anaerobic zone, 7.7 liters to the aeration zone and 4.4 liters to the sedimentation zone. The system was evaluatedfor 60 days with domestic wastewater from the cited community. During the evaluation, daily pH and dissolvedoxygen determinations were performed, and the Chemical Oxygen Demand (COD) was determined twice a week. Theinformation generated allowed us to observe that the system tended to stabilize during the three weeks of operation,achieving organic removal efficiencies in terms of COD in the anaerobic treatment of 53%, in the aerobic treatmentof 75%, achieving a total reduction in The entire 88% system and eliminating the odor. With data from the anaerobictank taken after 60 days of continuous work, it allowed to project the maintenance of the Pulinguí treatment plant thesame that must be realized in approximately each 4 years.