Evolution and Future of a Sustainable Integrated Water Supply System

As the result of ever-increasing demands on water resource, utilities around the world continue to develop, evaluate, and apply innovative technologies and operations. These include reverse osmosis treatment of brackish groundwater for potable use, reclamation of wastewater using tertiary treatment such as membrane bioreactor technology, and aquifer storage and recovery to capture water during wet periods for use during dry weather or drought conditions. Many utilities incorporate one of these technologies into their operations; however few have adopted and rely on all of these innovations. The city of Marco Island, located on the southwest coast of Florida, has been on the forefront of successfully integrating reverse osmosis for brackish groundwater treatment, membrane bioreactor for wastewater reuse, and a national award winning aquifer storage and recovery system into their operations to improve water supply sustainability and reliability. Noteworthy is that Marco Island is a relatively small resort community, with a seasonal high population of only 40,000 persons.Marco Island continues to evaluate the near and long term sustainability and reliability of its integrated water supply. This paper provides an overview of the challenges that have been overcome to establish the current integrated water supply system; develops and attempts to explain the trends in potable and reclaimed water use; describes the methodology Marco Island is developing to determine the most cost effective approach to meeting future water demands, and discusses the non-cost factors associated with the decision process.