Innovative Technology to Implement a Reuse Water Program

The city of Fort Myers has a population of approximately 58,000 and is located in Lee County, Florida. Over the last couple of years the city has experienced one of the highest growth rates in the country. The rapid increase in population in southwest Florida has stressed the available yield of the existing fresh water aquifers. Spurred by its involvement in the regional irrigation distribution system (RIDS) study, Fort Myers is looking for alternatives to make better use of its available water resources. One of the key components of the program is the reuse of wastewater for irrigation purposes. In accordance with Florida Department of the Environment (FDEP) regulations, tertiary treated wastewater can be used for irrigation of private and public facilities. For this purpose the treated wastewater has to pass through additional filters and chlorination before distribution.The city is currently operating a 1.51 million-gallons-per-day (mgd) annual average daily flow (AADF) reclaimed water production facility at its central reclaimed water production facility. The existing system consists of two parallel deep-bed sand filters and on-site chlorination facilities. As part of the city's water conservancy program the existing reclaimed water production facility will be upgraded to produce 6 mgd on an average daily basis. A second 9- mgd facility will be constructed at the city's second wastewater treatment facility, the south water reclamation facility. The produced reclaimed water will be sold to bulk users located within the city limits including golf courses, shopping centers, and city-owned recreational facilities.In order to select the most appropriate technology for the filtration of the effluent, the city has retained CDM to provide design and permitting services for the proposed improvements. As part of the project, the city performance-tested two different types of disk filters to determine the most appropriate technology for the expansion of its reclaimed water production facilities. Disk filters apply either cloth media or micro-strainer technology to filter remaining particles from the effluent.This paper will give the reader an overview of the city of Fort Myers' innovative water conservancy program and present the results of the disk filter pilot testing program. It will demonstrate disk filter technology can be a cost-competitive technology where space for construction of conventional filters is limited.