Water Treatment Facility
Project Profiles

• 1.0 mgd Seawater Reverse Osmosis WTP, Paradise Island, Bahamas

The Paradise Island Seawater RO plant was designed as a "fast-track" project to supplement the utility's potable water supply.  Raw water is supplied from two seawater shore wells.  Pretreatment includes antiscalant injection and filtration through cartridge filters.  The 250-horsepower high-pressure pumps are driven by diesel engines with installed electric motors as standby.  Twelve seven-element pressure vessels are included in each two-stage train.  Energy recovery turbines are designed to achieve maximum efficiency of the membrane treatment system.  Post-treatment of the product water includes acid pre-feed, degasification and stabilization using caustic soda and a calcite mixed media filter.  Disinfection is provided from existing gas chlorination facilities.  Concentrate disposal is via ocean outfall.

• 3.63 mgd Brackish Water Reverse Osmosis WTP, City of Sanibel, Lee County, Florida

3.63 mgd ultimate capacity with first phase of 1.215 mgd Reverse Osmosis Water Treatment Plant for the Island Water Association, Inc. (IWA), Sanibel Island, Florida, 1979.  Phased expansions of 0.6048 mgd were completed in 1986 and 1989.

The IWA Reverse Osmosis facility was constructed as a "fast track" project divided into several concurrent contracts.  Brackish water is pumped from three deep wells from the upper zone of the Suwannee Aquifer from a depth of approximately 1100 feet.  Pretreatment includes chemical additions of acid and polyphosphate.  The membranes selected for the project were spiral wound manufactured by Hydranautics Water System.  Post treatment includes degasification, stabilization, using caustic soda, and disinfection by gas chlorination.  Brine disposal is accomplished by outfall to the Gulf of Mexico.

• 3.0 mgd Membrane Softening WTP, South Lee County, Florida

The Gulf Utility Company Membrane Softening Facility was designed to supplement the existing water plant, providing treatment and softening of a new well field consisting of eleven wells drilled in the surficial aquifer.  Membrane softening was selected to provide potable water meeting existing and proposed State and Federal drinking water standards.  Pretreatment includes chemical additions of acid and an antiscalant compound.  A detailed membrane and equipment specification was prepared based on spiral-wound softening membranes.  Post treatment includes decarbonation using a gravity-type tray aerator, stabilization using caustic soda and disinfection using chlorine gas.  Byproduct concentrate disposal is accomplished through a reuse system blending wastewater effluent with the byproduct that is utilized as an irrigation course for two golf courses.  This project was completed in March 1991.

• 3.0 mgd Brackish Water Reverse Osmosis WTP, Pine Island, Lee County, Florida

3.0 mgd Ultimate 1.5 mgd Phase One Reverse Osmosis Water Treatment Facility for Greater Pine Island Water Association, Inc. (GPIWA).  Placed in service in 1993.  The GPIWA Reverse Osmosis Facility was designed to replace an existing plant that is obsolete.  Raw water is pumped from several deep wells located at the new plant site in the lower confines of the Hawthorne Aquifer system.  Pretreatment includes chemical additions of acid and an antiscalant compound.  Detailed plans and specifications were prepared for permitting, based on a spiral-wound, seven-element pressure vessel system to minimize hydraulic header losses.  The raw water quality is sufficient to allow a 10- to 15-percent blend at 85 percent system recovery.  Post-treatment includes degasification, stabilization using caustic soda and disinfection using chlorine gas.  Concentrate disposal is accomplished using an on-site evaporation/percolation pond system.

• 0.50 mgd Brackish Water Reverse Osmosis WTP, South Charlotte County, Florida

0.50 mgd ultimate capacity with first phase of 0.24 mgd Reverse Osmosis Water Treatment Plant for Southern States Utilities Burnt Store facility.  Placed in service in 1994.  The SSU Reverse Osmosis facility was constructed as a "fast-track" project.  Brackish water flows from three lower Hawthorne artesian wells, then "pressurized" using booster pumps located at the Process Building.  Phase One was limited to 0.24 mgd due to concentrate outfall constraints.  The plant was designed using a torpedo-type high-pressure pump unit and seven element pressure vessels to minimize hydraulic losses.  The raw water quality is sufficient to allow a 10- to 15-percent blend at 85 percent recovery.  Post treatment includes degasification, stabilization using caustic soda and disinfection using chlorine gas.  The concentrate flow is treated using a forced gas aerator unit to import dissolved oxygen.  The Burnt Store Plant is fully automated through PLC controls.

Project Profiles

Wastewater Treatment Facility