Reducing pollutants in wastewater treatment and reuse systems through constructed wetlands

Abstract

In the present study, the capacity for reducing contaminants in two systems for the sanitation and reuse of domestic wastewater that include constructed wetlands (CW) was evaluated, in a municipality of Los AltosNorte in the state of Jalisco, determining parameters such as: chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP) and specific conductivity (SC), both at the inlet and outlet of each system. The treatment systems are of the subsurface type, with horizontal flow, consisting of: pre-treatment for the separation of light substances (fats, oils, plastics, etc.) by flotation, and heavy materials (metals, sand, etc.) by sedimentation, CW with red volcanic stone as a substrate and Tule reed specimens and post-treatment that includes devices for chlorination and a stabilization reservoir, with a treatment capacity of 1.5 and 7 liters per second, observing significant reductions in the quantified parameters. Considering both the installation costs and the operational requirements of the systems for the sanitation of domestic wastewater with CW, these present an economically viable and environmentally sustainable alternative, mainly for rural populations that have adequate land and favorable weather conditions. Although the maintenance of these systems is considerably less than that of conventional treatments, it must be carried out regularly, mainly by removing sediment and floating materials in the pre-treatments, as well as periodically removing excessive biomass and vegetation in the wetland cells, to avoid short circuits in the water flow and guaranteeing adequate contact periods, including the less hot seasons.