Sistema de tratamiento para la depuración de las aguas servidas de Villa La Unión. Cantón Colta.

Abstract

This research work deals with the process design for the domestic wastewater treatment of Villa La Union city, canton Colta, Chimborazo province, with a caudal of 10,21 l/s produced by the domestic activities of 5 920 habitants up to the year 2020. The Environmental Impact Evaluation of the up today disposal of this city sewage yielded a result of – 515 poin ts, following a modified Leopold matrix and, when the propose system be applied, this negative value will be increased up to – 163 points, showing a 68 % of environmental quality enhancing. Taking into account the Villa La Union sewage weakness tested, it was designed a pretreatment composed by parallels bars system for the retention of big solids: a channel of 0,625 m; 15 bars with 0,015 m of width, and 0,015 m of thickness, with an each other separation of 0,025 m and, with an efficiency of 0,625. Fo llowing this primary treatment, a secondary one composed by stabilization ponds was considered. Two alternatives were taking into account, this is, (A) series of facultative and ripeness ponds; and (B) series of anaerobic, facultative and ripeness ponds. T he first one, with a minimum required area of 9 061 m 2 , give a BOD 5 elimination efficiency of 98 % and, more than 99 % of Coliforms elimination. The second one with a minimum required area of 6 262 m 2 , give a BOD 5 elimination efficiency of 88 % and, mor e than 99 % of Coliforms elimination. The estimated costs for the alternative (A) is about 16 310 USD, while the alternative (B) is about 10 873 USD.