Diseño del sistema de tratamiento de aguas residuales para el subsistema cosmopolita, cantón Baños – Tungurahua

Abstract

A system was designed to treat wastewater from the ""Cosmopolita"" subsystem belonging to the Baños canton, province of Tungurahua. Applying the analysis methodology, we proceeded to measure the discharge of the subsystem using graduated and timed containers; during five weekly days, four hours a day between morning and afternoon due to the conditions of the place, with intervals of fifteen minutes between each sampling. Five simple samples were collected in two hours which gave a daily composite sample for physical-chemical and microbiological analysis in sterilized plastic containers of 4L and 50mL. They were immediately transferred to the technical analysis laboratory of the Faculty of Sciences, ESPOCH. The average values of the wastewater were 477.25 mg/L Biochemical Oxygen Demand (BOD), 825 mg/L Chemical Oxygen Demand (COD), 98.5 mg/L Suspended Solids (SS), Fecal Coliforms 1.6x105 CFU/100mL and Total Coliforms 4.1x105 CFU/100mL, proving that these parameters are outside the limit allowed by the Unified Text of Secondary Environmental Legislation (TULAS). The evaluation of these parameters made it possible to establish the following processes to reduce contamination: twelve grids to eliminate medium-sized solids, a parshall channel to regulate the inflow, a primary sedimenter to eliminate suspended solids, an imhoff tank for biological treatment with two beds to dry sludge, and two anaerobic filters, reducing BOD5 by 70.56 mg/L and COD by 141.79 mg/L, i.e., with an efficiency of 90%. It is recommendable and feasible for the municipality of Baños to build the plant for a better social and environmental development of the population, thus complying with the current regulations; a previous update of the data and analyses that vary with time should be carried out.