The Challenge

The City of Lancaster, Ohio realized it had to replace its aging ion exchange water treatment facility with a new one to ensure quality for its residents. Fed by shallow, surficial wells, the old system was vulnerable to contamination and simply could not meet the city’s needs as population grew. The city hired URS as its engineering firm, who then pre-qualified and sent out for technical and price proposals to three firms. Harn R/O Systems was selected, based on its working knowledge of water treatment plants and its expertise in designing and building state of the art reverse osmosis facilities.

The Solution

The engineering firm had organized its alternative procurement to create the most efficient and effective project, from process design to construction of the physical plant itself. Harn R/O Systems worked in partnership with URS to design the membrane softening system, integrating various innovations that enabled the city to deliver clean water through membrane treatment. These innovations were then incorporated when the remainder of the project was subsequently contracted out. The primary contaminants in the raw water were hardness and iron, which is easily removed with membrane treatment. A 4 MGD sidestream is treated with iron removal filters and then blended with the membrane softening permeate to reduce post-treatment chemical usage. Thus the total water produced is 12 MGD − making this the largest membrane treatment facility in Ohio.

The Result

“Many firms are just equipment builders but we knew we needed someone who had the experience and knowledge to see the larger picture,” said Mike Pilutti, URS project engineer. “Harn had the capability both to deliver units to get the job done and to apply its expertise in the entire plant design so all systems and components were fully integrated. Harn helped design and build a facility that met the city’s immediate needs and enabled it to meet its future needs as well.”

Brief R/O System Specification

Owner: City of Lancaster, Ohio
Engineer: URS/Greiner Woodward Clyde
Application: Potable drinking water
Startup: 2004
Capacity: 8 MGD
Array: 35:15, 7-element vessels, 4 trains
Membrane Type: Dow Filmtec NF90-400
Operating Data
Feed TDS: 360 mg/l
Permeate TDS:
46 mg/l
R/O Feed Pressure: 100 psi
Recovery: 85%
System Features:
  • VFD driven R/O Feed Pumps
  • 1st Stage permeate back pressure valves with ability to convert to interstage boost in future