Evaluación del desempeño de un sistema de humedales tipo francés en condiciones no saturadas y semisaturadas para el tratamiento de aguas residuales domésticas

Abstract

Decentralized systems represent a sustainable, flexible and profitable alternative for wastewater management in small peri-urban and rural communities. Among these, French vertical flow constructed wetlands (FVFCWs) constitute a decentralized treatment option based on natural processes and low operating cost. The primary function of a wetland is the removal of BOD, but there are different configurations that enhance the removal of nitrogen, where the capacity to remove organic matter could be affected. In the present work, the robustness of French-type constructed wetlands to remove organic matter is studied under operational configurations that promote nutrient removal. For 4 months, pilot units were monitored with hydraulic and organic loads of up to 2 times those recommended in the design guides in two units (one unsaturated and the other semisaturated). The results show removals between 83% and 87% of the BOD in the two units under the different loads studied. These findings highlight the great robustness of this technology for BOD removal despite large variations in hydraulic and organic loads in the influent and the semi-saturated conditions of the filter medium. It is highlighted that it is possible to use the semi-saturated configuration in French-type wetlands without affecting their primary function of organic matter removal, which opens the possibility of generating anoxic zones in the wetlands that promote the removal of total Nitrogen.