Reinventar la Ciudad: Soluciones Verdes y Equidad Social para Comunidades Sostenibles (Coordinación)

The direct discharge of domestic wastewater into water sources represents one of the most significant pollution problems that requires urgent interventions to ensure the well-being and sustainable development of cities. Sustainable water management, appropriate wastewater treatment, and optimization of sewage services are essential aspects to preserve environmental quality, public health, and the well-being of the population. The city of Cuenca, Ecuador, designated in 2015 by the UN as an intermediate city— for which this organization has a particular interest in its sustainable growth— has a wastewater treatment coverage of 95%. The remaining 5% needs to be treated to prevent the pollution of the four rivers that run through it, which is why constructed wetlands emerge as an innovative solution that guarantees equitable access to basic services and minimizes environmental impact. The present study aimed to analyze the use of constructed wetlands as an alternative for the treatment of domestic wastewater in a neighborhood of the city of Cuenca, which discharges domestic wastewater directly into the Tarqui River, causing problems for its residents. Water samples were taken at a discharge point of the sewage system into the river, and two parameters were evaluated: biochemical oxygen demand (BOD₅) and suspended solids (SS). A horizontal subsurface wetland was designed based on a model for the reduction of organic matter, and a pilot station of the same was set up with Phragmites australis, fed with this water. The same parameters were re-evaluated at the wetland's outlet. The results indicate that the system has a pollutant removal rate with average percentages of 85% for biochemical oxygen demand and 87% for suspended solids, and that when compared to the Quality Standard. The results indicate that the system has a contaminant removal rate with average percentages of 85% for biochemical oxygen demand and 87% for suspended solids, and that, when compared to the Environmental Quality Standard and Effluent Discharge, it meets the established legal requirements. Artificial wetlands are an efficient and sustainable alternative for treating domestic wastewater, considering the capacity of these systems to capture and process contaminants from it.