Aurora Water interim director Dan Mikesell explains what motivates employees at the award-winning Charles A. Wemlinger and Thomas J. Griswold water treatment plants: “We’ve always felt it’s important to provide customers with the best water. Ten years ago we developed a culture that would help us achieve our goal of being an industry leader. The staff bought into that culture.”

Employees at each plant in Aurora, Colo., worked as a team to achieve the Phase IV Excellence designation (highest available) from the Partnership for Safe Water, improving plant processes along the way. These included a filter breakthrough alarm to notify operators of finished water turbidity increases, an annual filter surveillance program to ensure media performance, and a coagulant pilot plant.

The Wemlinger plant was the first in Colorado to achieve Phase IV, in 2008. The Griswold plant followed suit in 2011, making Aurora Water the only water utility in the country with two plants that have reached the Partnership’s top level.

 

Large utility

Aurora Water serves 75,000 accounts spanning 144 square miles in Adams, Arapahoe and Douglas Counties. Its water comes from the Colorado, Arkansas and South Platte River basins and is stored in 13 reservoirs and lakes. The city purchased water from the Denver water system before establishing an independent water system in 1949.

Besides the 80 mgd Wemlinger and Griswold plants, Aurora Water operates the 50 mgd Peter D. Binney water purification plant and the Sand Creek water reuse facility.

The Wemlinger and Griswold plants use direct treatment — filtration and disinfection. Equipment includes Hach laser turbidimeters, Chemtrac particle counters, Malvern Instruments zeta potential meters, Hach online chlorine and chlorine dioxide analyzers, Siemens Water Technologies and Milton Roy Company chemical feed pumps, Leopold (Xylem) Type SL underdrains, and EIM Controls (Emerson Process Management) and Rotork valve actuators. The plant staffs work often with manufacturers to beta test new equipment before it becomes commercially available.

Built in 1965, the Griswold plant was expanded in 1999-2001, with new media filters and valves, new chemical and administrative buildings, and a cover for the flocculation basin. The Wemlinger plant, built in 1981, was expanded in 2003-2004 with three new filters, new underdrains and new media for existing filters. Administrative and laboratory staff received new workspaces.

 

Raising the bar

Thirty-four Aurora water treatment staff took part in the Partnership for Safe Water program, including managers, supervisors, operators, maintenance staff, laboratory and quality assurance staff, and chemists.

The Partnership is sponsored by the U.S. EPA, the AWWA, the Association of Metropolitan Water Agencies, the Association of State Drinking Water Administrators, the National Association of Water Companies, and the Water Research Foundation.

The goal is to enhance drinking water quality and operational excellence in water treatment. There are four phases: commitment, baseline data collection, self-assessment, and an optional optimized system phase.

“When we decided to become active in the Partnership in 2004, we explained the program to the operators,” says Wemlinger supervisor Kirk Watson. “Some of them were skeptical because it sounded like a lot of extra work, and they wanted to know what was in it for them.”

Management listened to the operators’ ideas and suggestions. In response they modified the SCADA system for more efficient operation and added sampling points for better monitoring. “As the operators saw this, they became more involved and asked what they needed to do to make the Partnership program work,” says Watson.

 

Operations team

Six operators at the Wemlinger and Griswold plants are responsible for monitoring process flows, mixing chemicals and determining chemical dosages based on both online and zeta potential meter readings, monitoring filter effluent for turbidity and particle counts, conducting quality tests on raw and treated water, and documenting the use of chemicals and biological processes. They also clean the filters and repair and maintain plant equipment.

Maintenance workers at the two plants perform preventive and corrective maintenance on all the equipment and work closely with the operators to make sure the equipment is operating at its best. Lab personnel provide data that assists operators with treatment decisions and work with the operators on special projects.

The Wemlinger operations team includes supervisor Watson (20 years with Aurora Water), chief plant operator Hart Krumrine, and treatment plant operators Mike Creazzo, Bill Fulbright, Steve Keltner, Joe McDonald, Tillman Petty and Erik Tameler. Collectively, they have more than 60 years of experience with Aurora Water.

The Griswold operations team, with more than 50 years of experience at Aurora Water, includes supervisor Ralph Haight (15 years), chief plant operator Charles Collins, and treatment plant operators Jo el Conger, Nicolaas deJonge, Les Griffin, Bill Montgomery, Ralph Precord and Dan Winchell.

 

Optimizing the process

The Wemlinger team spent a year on the Partnership program’s self-assessment stage, where they scrutinized the entire process. They sent a report to the Partnership committee and were graded on process strengths and weaknesses. “Plant staff looked at how they could raise the bar,” says Mikesell. “It’s all about optimizing what you do.”

Watson agrees, “We were all on a learning curve. We brought our operations, maintenance, SCADA and administration staff together and reviewed the AWWA self-assessment guide page by page. If something needed clarification, we called experts at the AWWA Denver headquarters to answer our questions.”

The staff learned a lot during the process and applied the knowledge when Griswold went through the program. Although both plants achieved Phase III in 2006, it took Griswold longer to achieve Phase IV. “The Griswold team recognized that they hadn’t obtained the level of optimization they wanted and decided to wait until 2011 to submit their Phase IV report, when they were confident they had made their plant one of the best in the nation,” says Watson.

While teamwork and perseverance helped the staff reach the Phase IV goal, a competitive spirit helped too. “When Wemlinger got it, Griswold wanted it too,” says Mikesell. “It was friendly competition.”

 

Tackling turbidity

One result of the program was optimized finished water turbidity for both plants. “We had to make sure we never exceeded 0.1 NTU,” says Watson. “To do that, we had to ensure no breakthrough from the filter. We installed a breakthrough alarm so operators are notified if the turbidity increases, and they can take that filter out of service.”

Operators also made sure the turbidity meters were properly maintained, and that the flat-line alarm was operating properly. That alarm notifies them if the turbidity doesn’t change, so they can take the filters offline. Says Watson, “We could leave the filters running and take grab samples, but it is our policy to take them out of service until the turbidity meter is repaired. That way, we don’t risk any chance of a violation.”

The operators hold “worst filter run meetings,” where they review data from the previous month’s filter runs. “We analyze the turbidity data and work to understand when it occurred during the filter run and what caused it,” says Watson. “Although our water quality is high, by doing this we can see if there might be a trend starting that we wouldn’t see otherwise, and we can address it before it becomes a problem.”

Through these meetings, operators saw that one filter had the worst run two out of three months. They adjusted the valve timing on the filter, fixing the problem.

 

Training and advancement

Operators from both plants meet a few times a month to talk about what is going on. “By putting more heads together, they come up with ideas for how to solve various issues they might be having or to improve a process,” says Watson. The staff is cross-trained at the two plants so they can fill in for each other if necessary. Turnover is low.

An in-house training program conducted by Aurora Water staff or outside experts from engineering firms and regulatory agencies helps operators stay up to speed on equipment and technology. Operators also can attend the Rocky Mountain Operators’ School and the AWWA Rocky Mountain Section’s one-day Actions Now seminars. Red Rocks Community College in Lakewood, Colo., offers environmental, engineering and water quality management degrees.

“We have had operators earn degrees and move on to other positions,” says Watson. “Bobby Oligo, our superintendent of water treatment, started with Aurora Water as an entry-level operator and worked his way up.”

 

New skills

The Partnership program has helped operators acquire new skills. For example, they now maintain and calibrate turbidity meters, chlorine analyzers, pH meters, chlorine dioxide analyzers and particle counters. Retired staff members returned to the plants to train operators on the equipment.

Operators are also responsible for filter surveillance. “Filters are the workhorses of our facility, so we do core sampling to make sure the media still meets specifications for optimum performance,” says Watson. “We also measure media depth to ensure that we have not lost any media during normal operation.”

The operators are involved in special projects, such as testing different coagulants using a small-scale pilot plant. “We can’t run tests on the full-scale plant, because the coagulant might not work,” says Watson. “With the pilot plant, we can test coagulants to see if they work as efficiently as those we are currently using. We can then use the information to do a cost-benefit analysis on whether changing coagulants is warranted.”

Teamwork allows the operators to better solve problems. “They are never complacent,” says Watson. “If there is an issue with the process, they make sure the other operators know about it, and they work as a team to solve it.”

Last year, for example, they noticed that the particle counts almost reached the plant’s internal limit, and then decreased later in the day. “This is a testament to the amount of attention our operators pay to the process,” Watson says. “We were still 100 percent in compliance, but it wasn’t our normal, so they wanted to know why.”

The operators worked with the lab staff to diagnose the problem. “It turned out we were shearing our floc particles, and by taking a couple of the floc basins out of service, we were able to correct it. The operators didn’t give up until they figured out what was wrong and fixed it, which took about three weeks.”

 

Fighting fires

Operators’ challenges include turbidity increases from spring runoff. As the snow melts in the high country, water runs into the streams at higher rates and can carry additional sediment. This can also happen when heavy rains cause watershed washouts.

Chemicals used in fighting forest fires have also presented problems. “The Hayman fire in 2002 affected the main watershed,” says Watson. “The flame retardant had a high phosphorus content, and some of that got into the reservoirs and caused algae blooms. That affected the water’s taste and odor.”

In response, operators monitored the water quality more often and minimized the smoky taste and odor with chlorine dioxide disinfectant. “We use this as our primary disinfectant, and it has properties that help minimize taste and odor issues,” says Mikesell. “Utilities that didn’t use chlorine dioxide received complaints from residents.”

Other challenges include reducing treatment costs and energy consumption. “We want to lower our total cost to treat the water by researching and testing new chemicals,” says Watson. “We are also looking at ways to reduce backwashing so we can cut electrical costs and sludge production.”

 

Future goals

The Wemlinger and Griswold plant teams plan to retain Level IV Partnership status. “We have to submit a report every year listing what we have done to continually improve,” says Watson. “I’m on the Partnership review committee now, so I get to review other utilities’ reports. It’s something I can learn from.”

Mikesell points out that the Partnership is a major accreditation: “It’s something you have to live.” Aurora Water signed on for the Partnership’s Distribution System Optimization Program, and operators have already started collecting data and assessing system performance.

Says Watson, “We will look at water quality or disinfection residuals and how they are maintained, hydraulic reliability or pressures within the system to make sure they are optimized, and physical security, which will be measured by the number of main breaks the system incurs.”

The Wemlinger plant hopes to win the 2012 water taste test, sponsored by the AWWA Rocky Mountain section. “We won first place in 2009 and 2011, so it would be great to win again,” says Watson.

The Partnership designation and the taste test awards are just a few of the honors Aurora Water has achieved in the last seven years. There will likely be more. “Our operators are special because they are committed to delivering the best quality water they can, and that is what motivates them every day,” says Watson.

Mikesell agrees: “They believe in and have embraced that vision.”