This article originally appeared in WQP June 2020 as "Time for a Check Up"
Global Water Services is a service provider to the industrial water treatment industry. We operate worldwide to provide evaluation, training, service, system upgrades, rentals and replacements to clients where failure of critical water treatment systems will cause immediate detrimental effects to the facility or process.
The subject of the project discussed here is a Midwest hospital that had a 4-inch inlet/outlet service line in a quad-tank configuration water softener system. An Allen Bradley PLC controlled the inlet and outlet diaphragm valves, as well as the Fleck 3150 (2-inch) regeneration valves for each vessel.
This system served the entire 650-bed hospital, medical teaching hospital and medical offices on a 6-square block campus in a major metropolitan area. There was a litany of issues with the system, and Global Water Services implemented changes to a variety of the components over a seven-year period.
Some of the issues were low flow channeling, low throughput totals with premature hardness leakage, lack of control backup, regeneration and diaphragm valve service intervals being short, tank liner issues, no manual operability for emergency operations, brine silo was small resulting in less than full bulk deliveries, and high chloride discharge levels to the city sewer.
As this system serviced the hospital service water, boiler feed, cooling tower makeup, and a majority of ancillary system supply, complete shutdown of this system was never a consideration. The system had to run all the time. Fortunately, being a four-tank system, Global Water Services was able to implement all changes with at least two units available for service at all times.
A Seven-Year Remediation Project
One of the first projects was to remove all the material from each vessel in succession, next white metal blast the tank liner, and prime and recoat with two-part epoxy finishes. Once heat cured, the team installed stainless-steel internals and loaded fresh gravel and new resin. The face piping was replaced with butterfly valves, and a new control system and PLC was mounted next to the existing controller.
After each unit was completed, it was tested with the new control system and brought online. Both controllers were maintained until the third unit was brought onto the new controller. Once one vessel remained, the old control system was removed and the new system PLC was in control of system operation. After the four vessels were completed, the team demobilized for a period of nine months.
The next system to remediate was the brine silo and measuring tank system. Global Water Services had included a brine reclaim feature with the new PLC. A temporary brine tank system was set up. Removal of the old brine measuring tank; piping and controls; reclaim piping; and cleaning 3 feet of mud out of the existing brine silo was accomplished. This upgrade yielded a 22% reduction in salt consumption. An additional 30% increase in throughput was gleaned by switching from a standard injector in the 3150 valve to a penberthy brass eductor increasing brine concentration from 8% to 12%.
The remediation of the brine silo and measuring tank system resulted in a 22% reduction in salt consumption. The addition of a 17-ton brine silo tank allowed the hospital to take a full truck load of salt, as well. The entire upgrade, which spanned more than seven-years, reduced salt consumption, improved performance and saved water.
The next phase of the upgrade included adding an additional 17-ton brine silo tank, which would allow the hospital to take a full truckload of salt. As the hospital was paying full freight for a half truck load, the resultant savings were high because the only additional cost was the salt cost.
After a civil and structural engineer both reviewed the weight loading to the building floor, Global Water Services rigged a new tank into parallel position with the existing unit. The piping for brine draw, salt fill, venting, controls, water fill and reclaim were all piped so that either vessel could be used with the other isolated for future maintenance.
This entire process reduced salt consumption, saved water, improved performance and reliability, and reduced maintenance costs. Global Water Services continues to assist this client with consulting, service, training and equipment maintenance throughout the hospital system.