Integrated Wastewater Management in the Lake Atitlán Basin: An Ecological Engineering Challenge GREGORY HINDS1, KELLY VANNOY1, ELIZABETH JACHENS2, STEWART OAKLEY2* 1University of South Florida, Tampa, Florida, USA 2California State University, Chico, California, USA *Corresponding author: email:
[email protected], Tel: 1-530-898-4976 Initial Study Conducted: 2012 Report Prepared: 2013 Revised: 2014 Completed: 2015 ABSTRACT Lake Atitlán, Department of Sololá, Guatemala, is undergoing rapid water quality degradation as a result of the ongoing discharge of wastewater from the basin’s population (>250,000) into the lake. This is a direct threat to the ecology of the lake, to public health, and to the future economic stability of the region. The purpose of this paper is to establish and evaluate wastewater management alternatives for the mitigation of this threat. It is imperative that wastewater management within the basin prevents the anthropogenic loading of nutrients into the lake. Thus, treatment processes for nutrient removal before discharge to the lake and wastewater export were identified as the only practical options. Accordingly, the following two alternatives were evaluated and compared: (1) decentralized wastewater treatment within each municipality through the use of secondary and tertiary treatment systems for nutrient removal; and (2) export of wastewater from each municipality via an integrated pipeline network to a centralized wastewater stabilization pond system outside of the basin designed to enable effluent reuse in agriculture and the recovery of energy through anaerobic pretreatment. A life cycle cost analysis (LCCA) approach was taken in comparing the alternatives. Capital costs, projected operation and maintenance costs, and wastewater valorization potential over the 20 year design life, ranging from 2016 to 2036, were included in the LCCA.