Manejo integrado de aguas residuales dentro y fuera la cuenca del Lago Atitlán

Abstract

Lake Atitlán receives wastewater discharges that threaten water quality and public health: 100,000 people use the lake as a drinking water source without purification. Cyanobacterial blooms in 2009 and 2015 demonstrated the degradation and severity of the situation. There are 19 wastewater treatment plants in the basin and none were designed to remove pathogens and nutrients. To improve wastewater management, there are three options: (1) wastewater treatment through the use of activated sludge and tertiary processes to remove pathogens, nitrogen and phosphorus to low levels for discharge to surface water; (2) integrated wastewater management, with reuse in agriculture, modeling two plants in Sololá that have operated for more than 20 years; and (3) export the wastewater out of the basin with an underwater pipeline, pumping, hydroelectricity generation, treatment and reuse in agriculture. Sustainability was compared through life cycle analysis, investment costs, operation and maintenance; and valorization for hydroelectricity, fertilizers, and reduction of the carbon footprint. Results, option (1) is not possible, the required technologies do not exist in Latin America, option (2) is more difficult and expensive than option (3) wastewater export, where additionally there is experience in design, construction, and operation and maintenance, with hydroelectric potential of 5 MW, and reuse in agriculture with 788,000 kg/year of N and P produced in 2045. Wastewater export has worked in several countries, and was implemented 50 years ago by the Municipality of Guatemala to protect Lake Amatitlán, but the export of wastewater was not completed and today it is a polluted lake.