James City Service Authority Five Forks Water Treatment Facility

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1 W e w o r k i n p a r t n e r s h i p w i t h a l l c i t i z e n s t o a c h i e v e a q u a l i t y a n d r e l i a b l e w a t e r s o u r c e.

2 Design Team n Jcsa Owner/Operator n Buchart Horn Prime Engineer n Watek Engineering Process Design n Rostek Associates Technical Consultant n Hartwell Engineering Scada Integration n Aes Site Work Design n Russnow & Kane Hydrogeologist n Alan Outlaw Archeological Assessments Contractors n Mid-Eastern Builders General Contractor n Itt Aquious RO Process n Walter C. Via Site Work n C.D. French Concentrate Main n Well Construction Sydnor Hydro Equipment n Protec Pressure Vessels n Dow Filmtec RO Membranes (model #BGW400) n De Loach Degasification System n Parker Cartridge Filters and Vessel Housings n Toshiba Variable Frequency Drive n Allen Bradley Motor Control Center n Prominent Chemical Feed Pumps n Poly Processing Chemical Storage n Afton Vertical Turbine Feed and High Service Pumps n Cummins Emergency Generator n American Turbine Submerisible Well Pumps Instrumentation n Rosemount Pressure & Analytical Trasmitters n Foxboro Flow Metering n Hach Chlorine Analyzer n Ashcroft Differential Pressure Control n Milltronics Level Monitor n Pressure Systems Inc. Transducers

3 Introduction James City County is a 144-square mile municipality located at the head of the Virginia peninsula, between the James and York Rivers. James City Service Authority (JCSA) operates the largest solely dependent groundwater based water system in the Commonwealth of Virginia. The majority of its groundwater supply system is derived from the Potomac and Chickahominy- Piney Point Aquifers. The JCSA s water system currently operates a Central Water System and six independent systems. One key component of the Central Water System is the which consists of five on-site wells drawing brackish groundwater from the Middle and Lower Potomac Aquifers. To make the water potable, a reverse osmosis treatment process is used to extract salts and other minerals. This extraction, also known as concentrate, is discharged through a pipeline into the James River near the Jamestown Ferry. For every five million gallons of potable water produced, approximately one million gallons of concentrate will be discharged into the James River. Site Description The location was chosen because the well field could be located on site. The site is also within close proximity to major water distribution lines, close proximity to concentrate discharge location and close proximity to demand centers. Awards n 2006 Engineering Excellence Grand Award American Council of Engineering Companies of Virginia (ACEC) n 2006 Membrane Facility Award American Membrane Technology Association (AMTA) In recognition of an exemplary cost effective application, design and operation of a 5MGD Reverse Osmosis membrane facility.

4 Pre-Cartridge Filters Four cartridge filters are provided on the raw water line for the Lower Potomac Wells to filter the raw water prior to the RO treatment system. The four Lower Potomac cartridge filters are designed to accommodate raw water flow of 3,340 gpm with one cartridge vessel out of service. The cartridge filters remove particulate down to one micron. When all four skids are on-line, two Lower Potomac wells are utilized with the third well available as a backup. Two cartridge filters are also provided on the raw water line for the Middle Potomac wells to filter the raw water prior to blending it with the permeate water from the RO skids. The Middle Potomac cartridge filters are designed for a flow of 800 gpm with one cartridge vessel out of service. When the skids are on-line, one Middle Potomac well is utilized for blend water and second Middle Potomac well is available as a back-up well.

5 RO Treatment Skids Membrane Vessels Four reverse osmosis (RO) treatment skids are provided in the treatment facility for desalination of the raw water withdrawn from the Lower Potomac Wells. The RO skids were furnished with a two-stage membrane system complete with piping and instrumentation. The first stage consists of 20 vessels. The second stage consists of 10 additional vessels. Both the first and second stage vessels contain six membranes each. Raw water discharged from the RO feed pump will be pumped to the first stage membranes of the RO skid. The permeate will be discharged to the permeate line. The concentrate from the first stage membranes will become the feed water for the second stage membranes. The permeate from the second stage will combine with the permeate from the first stage and is piped to the common RO skid total permeate line. The concentrate from the second stage is piped to the common concentrate line which is discharge into the James River.

6 Process Flow Diagram

7 Water Quality Data Alkalinity Chloride Fluoride Sulfate Calcium Iron Magnesium Potassium Sodium TDS MP LP Finished Water < Normalization Data 700 Normalized Permeate Flow 600 Flow (gpm) Operation (Days) 1st Stage 2nd Stage System 40 Differential Pressure Pressure (psid) Operating Time (Days) 1st Stage 2nd Stage

8 119 Tewning Rd. Williamsburg, VA jamescitycountyva.gov/jcsa