EXAMINING THE POTENTIAL FOR IMPROVED WETLAND DESIGN AND EFFICIENCY IN AKUMAL, MEXICO USING LOCAL GEOMATERIALS

Waterborne disease and sewage pollution are global threats to human and environmental health throughout the world. In many areas, constructed wetlands are being implemented as a low-cost, ecologically based technology to locally treat domestic wastewater prior to discharge. In the tourist village of Akumal on the Eastern Yucatan Peninsula an estimated 50 systems exist. Yet investigations of some of these systems indicate problems with design and performance, linked to the high solubility of limestone aggregate, coarse aggregate size, and the lack of a liner. This research explores the geotechnical and hydrogeologic properties of local materials to improve wetland design and efficacy. Alternative aggregate sources include dolomite in the Reforma region which has lower solubilities than current aggregate and also have mineral impurities of goethite and palygorskite which are conducive to waste treatment. Beach sands have been shown to have better hydrogeological properties that current aggregates but have significant Mg-calcite and aragonite making the materials more soluble than current aggregate choices. Recent investigations have identified clay materials suitable for liners in the systems. These include Ca-montmorillonite and palygorskite clays from the Reforma region. The goal of this work is to provide a scalable working model that will ultimately improve the efficiency of existing engineered wetlands in the Yucatan while keeping the economic demands of maintaining these systems to a minimum through the use of locally available materials.