Artificial wetlands system for the eutrophication control of the lake of Bosque San Juan de Aragón

Abstract

The lake of Bosque de San Juan de Aragón (LBSJA, for its Spanish acronym), occupies a 12 hectare area. The lake is eutrophicated due to an activated sludge system, known as "Tlacos", that carries partially treated water into the lake  and contains nitrogen and phosphorus concentrations that trigger the growth of microalgae. In this study, we describe relevant aspects of the design, construction and operational start of a treatment system based on artificial wetlands (AWs ) built in the LBSJA. The AWs occupies an area of about one hectare; it was designed to purify an average of 250 m3d-1 of water. The system consists of a limestone aggregate filter, a settler, a subsurface flow artificial wetland (SSFAW), a surface flow artificial wetland (SFAW), and a gabion wall filter. Water that feeds the system comes from both the conventional treatment  plant of "Tlacos" (WWTP-Tlacos) and that contained in the lake itself. Our results show an 80% reduction of contaminant content. The later represents a superior quality than that established in the environmental standards for treated water from water bodies used for recreational purposes.