Optical laboratory optimizes water treatment process with redundant system
In Baltimore, Md., UnitedHealth Group’s Spectera Vision Laboratory relies on clean water throughout its production process. The laboratory, which manufactures optical lenses, uses reverse osmosis (RO) water in its regular plant, rinsing lenses from one process to the next. Anti-reflective (AR) coatings are applied in the facility’s AR lab, which requires ultrapure water. The AR lab is a complete clean room, and the coatings are applied using lasers and a vacuum. If the lens is not completely clean, the coating will not stick, so having water of an ultrapure quality is vital for production.
Pure Water Works had previously designed two small systems for the facility. An RO system handled basic production in the main lab, and another system produced ultrapure water in the AR lab. Nearly 15 years later, in December 2016, UnitedHealth tasked Pure Water Works with designing and installing one system to serve the entire facility.
Pure Water Works is based in Traverse City, Mich., so designing, installing and acting as general contractor on a project in Baltimore was no easy feat.
"It’s hard to act as a [general contractor] when you’re not there,” said Bill Siegmund, managing director for Pure Water Works. “But we had the advantage of having worked with a particular plumber and a particular electrician that we had confidence in. We were able to pull it off that way.”
The team was on a strict time schedule, transporting materials across the country and working onsite in only six days.
“Usually all the equipment is just sent out onsite, but because of that extreme time window that we had to work in, I actually sent two of our lead technicians from here in individual trucks with everything that we might possibly need,” Siegmund said.
Work began on a Monday, and the crew worked several 16-hour days throughout that week to prepare for the switch to the new system. Converting the two treatment systems into one had to be done between 2 p.m. on Saturday and 6 a.m. Sunday morning. Because of the sterile nature of the facility, cleanup was particularly important, and all dust and debris had to be completely eliminated before the lab could resume operations.
The weekend installation combined with the rare, high-purity equipment required meant the team that traveled from Michigan to Maryland had to come equipped with as many supplies as possible to be prepared for any unexpected difficulties during installation.
Ultimately, the project was completed on schedule, with a price tag of less than $100,000.
“We’re really proud of the job and our guys,” Siegmund said. “Our guys just did a fabulous job.”
Twin RO systems are in alternate operation so no part of the system remains idle for long. The entire treatment process is redundant, allowing the system to operate continuously even if something goes wrong.
The system consists of deep bed backwashing catalytic carbon, followed by a dual-tank water softening system. Water then enters twin 7-gal-per-minute RO systems with a permeate flush. It then is sent to a 1,000-gal storage tank with a 0.2-μ air breather. Two variable-speed drive delivery pumps pump the RO water to the main plant, while two separate variable-speed pumps drive the RO water through a twin deionization (DI) system. Having two pumps in operation for each water type ensures that if one goes down, there is always a backup.
In the DI system, water goes through an ultraviolet light, followed by a 0.2-μ filter on a loop that circulates 24/7. The entire system is equipped with water quality monitors and alarms throughout the treatment process.
Because the treatment system operates continuously, redundancy was an important requirement of the project. This redundancy means each portion of the treatment process had to be not only duplicated, but also alternated during operation so nothing remains idle for too long.
“I had to design electronics that would make everything twin alternate, so when the tank gets full it automatically switches to the next RO [system],” Siegmund said. “When a certain frequency on the variable-speed drives for the pump is reached, it switches to the other pump and they switch back and forth with every resin bag change. Not only did we have to have redundancy, we had to make certain that all lines, all pumps, all equipment, were being used with the same frequency.”
The optical facility requires ultrapure water in its AR laboratory. This DI system includes an ultraviolet light and 2-U filter
Because of some personnel turnover at the laboratory, Siegmund traveled to Baltimore in November 2017, a month ahead of the system’s one-year service date, to go through the training process with a new maintenance crew.
“Our systems function totally automatically,” Siegmund said. “If [the maintenance crew] never looked at it, it would still run fine until something catastrophic happened.” Alarms and strobe lights are installed throughout the system and are activated if water quality declines or if any part of the system malfunctions.
The crew keeps logs with data from each RO and DI processes to monitor their performance, which Siegmund then uses to keep tabs on the system and be proactive when it comes to maintenance.
“I want to touch wood whenever I say something like this, but the system has been flawless and the guys have been doing a really good job of maintaining it,” Siegmund said.