Análisis de la sostenibilidad operacional de las plantas de tratamiento de aguas residuales del área rural de la ciudad de Cuenca

Abstract

Centralized wastewater collection and treatment systems are well known for being expensive to build and operate, especially in areas with low population density and high distances between houses. Therefore, ETAPA has been using decentralized systems because they not only provide a long-term solution for small communities, but they are also economically viable. However, several inconveniences have been associated with Operation and Maintenance (O&M) of these systems, mainly represented as high costs. For this reason, the aim of this study is to compare three operation scenarios. The first one is to keep the continuity of the existing systems, the second, repairing them and the third one the star-up of a new plant. Indeed, the operational sustainability of the decentralized Wastewater Treatment Plants operated by ETAPA were analyzed. Hence, existing information of the O&M, as well as interviews to employees in charge of these activities were gathered. The results revealed that the biggest contribution in the total cost of O&M is the workers' salary. Also, there are excessive maintenance works that are not related to the size and technological configuration of the plants; which are mainly conducted following a schedule, and not as a required action. Finally, the financial analysis showed the potential profitability of the inversion destined for repairing existing systems, with a cost reduction range between 27-94% in O&M. Likewise, repairing current systems turned out to be 95% cheaper than investing in the star-up of a new plant