Marshalltown Water Works optimizes treatment plant water quality and distribution system performance and receives Directors Awards for both.
For many years, employees at Marshalltown (Iowa) Water Works were used to doing things a certain way. The Partnership for Safe Water Program changed all that.
Three years ago, the utility went through the Partnership’s self-assessment process to optimize its distribution system. The next year, it took part in a groundwater treatment assessment and optimization pilot program for the conventional lime softening process.
The team identified performance-limiting factors, developed system optimization action plans and submitted two peer-reviewed reports, one each for the distribution system and treatment plant. “We are already a very efficient operation, but there were things we identified during self-assessment that showed we could do better,” says Tim Wilson, director of water production. Those included better data collection and better-documented standard operating procedures.
Treatment plant operators focused on the lime softening system parameters, while distribution staff analyzed the hydrant flushing process and chlorine residual testing. “We asked ourselves how consistently we were able to produce the same quality of water through our lime softening process,” says Wilson. “We also asked what we could do to reduce the turbidity of the water coming off our softening basins. That reduces the turbidity going to our filters and increases our filter runtimes.”
The hard work paid off. In 2016, the utility received the Partnership Directors Award for both water treatment and water distribution system assessment/optimization. Marshalltown became the second utility in Iowa to receive the Directors Award for treatment and the first for distribution.
The utility celebrates its 140th anniversary this year, and some of its distribution piping is nearing the replacement stage. “Our trustees and staff regularly monitor the equipment condition through our five-year capital improvement plan,” says Steve Sincox, general manager and CEO. “We’ll be starting to replace those old pipes soon.”
The water treatment plant, built in 1977, went through a major upgrade in 1997, from 10 mgd to 12 mgd. The upgrade included rapid sand filter rehabilitation, aerator replacement, sandblasting and painting of the solids contact units, SCADA improvements, and an additional lime-settling pond for softening residuals storage.
Today, the plant serves about 29,000 people in Marshalltown and sells 30 percent of the treated water to the Central Iowa Water Association, a rural water provider. Source water comes from nine deep wells that provide a stable, high-quality supply.
“It’s clear coming out of the ground, but hardness is around 450 to 500 ppm,” says Wilson. “We use aeration to drive off the dissolved gases.” The water is softened to less than 130 ppm; average finished hardness is 110 to 115 ppm. Lack of turbidity can be a challenge. “There are not a lot of solids to start with, and without that it can be a little more difficult to generate the floc needed to facilitate the softening and clarification process,” Wilson says.
The final product won the Best Tasting Drinking Water competition in 2008 and 2009 from the AWWA Iowa Section. “While we do a lot to improve the raw water at the treatment plant, the minerals that we leave behind contribute to the taste, along with the exceptional work our outside crew does in the distribution system,” says Wilson.
Optimizing for quality
A team of 20 worked together to improve distribution system and treatment plant operations. Says Sincox, “When we started with the self-assessment process, we went through piles of data, which showed us what we are really good at and what we needed to improve. We asked ourselves what we could fix right away and what was more capital-intensive that we could plan for down the road.”
The staff fixed the simple, inexpensive things first and then concentrated on the more challenging areas, like the pipe gallery. “A limitation in the pipe gallery for our filters does not allow us to control flow as consistently as we would like as water passes through the filter gallery,” says Wilson. “While the quality of our effluent is still very good, better flow control would provide a much more consistent product and allow us to more consistently meet the Partnership goals. This is something we will continue to plan for and work toward in the future.”
In April 2016, the plant began a $6.7 million upgrade. “When Alliant Energy asked to purchase water from us for their new Marshalltown power plant, we hired Fox Engineering to evaluate our water system and determine if we had enough capacity,” says Sincox. Although the treatment plant does have enough capacity, the staff decided to repair, rehabilitate and upgrade some of the older equipment to help accommodate the new demand. The upgrade, to be completed in March 2017, includes:
- Replacing 1 1/2-million-gallon in-ground reservoir with 2-million-gallon reservoir
- New high-service pump building
- Two 3 mgd horizontal split case pumps (Flowserve)
- New lime slakers (MERRICK Industries)
- New SCADA system, Allen-Bradley ControlLogix hardware, Rockwell FactoryTalk View software (Rockwell Automation)
- New 1 1/2 MW standby emergency generator (Caterpillar)
- New switchgear and outdoor transformer
- Sandblasting and painting of existing solids contact units
“Replacing the lime slakers will improve the consistency of the lime feed, thereby improving water quality,” says Wilson. “The SCADA system replacement will allow better monitoring of chemical feed systems, and the new reservoir will improve circulation of the finished water.”
Many Marshalltown staff members have spent most or all of their careers with the utility. Sincox holds Grade IV Water Distribution certification and has been with the water works for 21 years. Wilson holds Grade IV Water Treatment and Water Distribution certifications, and has been at the treatment plant for nine years. Reporting to him are:
- Treatment plant operators Bruce Frisk (24 years), Jon Reuter (17 years), Ryan McFarland (one year) and apprentice Pat Bell
- Ed Phillips, operator and maintenance employee (17 years)
- Dana Pope, director of distribution (eight years)
- Utility workers Ronald McWilliams (15 years), David Rebik (15 years), Brian Kreimeyer (14 years) and Jordan Dolash (two years)
- Jared Wall, utility maintenance mechanic (five years)
- Meter service employees Mike Ellis (10 years), Jennifer Hulin (nine years) and Doug Knoll (16 years)
Operators work two 12-hour shifts and two eight-hour shifts (four days on and three days off) each week. Phillips fills in when operators are on vacation. The staff gives back by giving plant tours and presentations to the general public and student groups.
“They give tours to third-graders, high schoolers and sometimes students from Marshalltown Community College as part of their science classes,” says Wilson. “Sometimes we have two to three groups a day. Different operators take different groups to give the students fresh perspectives, and also to save our voices.”
Prepared for floods
The treatment plant and wellfield sit in the Iowa River floodplain. “We are continually adding and improving infrastructure to make sure our equipment is above the 100- and 500-year flood projections,” says Sincox. The plant saw record flooding in 2008, although the infrastructure and equipment were not affected.
The utility’s nine wells average 600 to 4,200 gpm. The larger wells are equipped with variable-frequency drives for greater flexibility in dialing in the flow needed on a given day. Since 2008, all wellheads except one have been raised above the 100-year flood level. The exception is a 700 gpm well that is on the lower end of the flow range but on the high end of the raw water ammonia range.
Says Sincox, “Our operations staff suggested that we add a variable-frequency drive to this well, which will essentially make it into a chemical feed well.” The plant uses chloramine as its primary disinfectant, and the ammonia needed to generate the chloramine is already present in the raw water.
“Being a lower-capacity well, it is not very efficient to run it with any combination of the other wells, since the raw-water ammonia is too high,” Sincox says. “By adding a variable-frequency drive, we can dial back the flow, which will help us to better meet demand and maintain quality.”
One challenge facing the utility in recent years is staff turnover. “This is a great place to work and historically we’ve not had a lot of turnover,” says Wilson. “But, we’ve had some people retire or move on the last two years, and they are hard to replace. It takes a lot of training and time, and those who are still here have to juggle their hours. So it affects everyone.”
Three years ago, the plant started an apprentice program, in which experienced operators train new ones. “We got someone trained and certified in 12 months by job shadowing with an existing operator,” Wilson says. “It worked out well.”
On the distribution side, the main challenge will be replacing water mains. “We inventoried all our mains and looked at the breakage point,” says Wilson. “We have experienced higher breakage in pipes from the 1920s, and we’ve targeted these for replacement in 2017.”
In the meantime, the plant will continue with the Partnership program. “It’s all about continuous improvement,” Sincox says. “Some areas that need work are capital-intensive, but it’s a goal we’re shooting for. The most valuable part is the self-assessment. Although it can seem daunting, if you systematically check off each area that needs to be improved and then implement that change, it gets easier. The payback in terms of what you learn makes it all worthwhile.”
The water distribution team at Marshalltown Water Works came up with a unique way to teach the community about the benefits of tap water over bottled water.
“The staff was tasked with building a watering station to promote our tap water and educate people about the exorbitant cost and waste associated with bottled water,” says Steve Sincox, general manager and CEO. “Rather than create a freestanding device that would need to be loaded on pickup or trailer, they recommended repurposing an old portable air compressor that hadn’t been used in over a decade.”
All four distribution employees dismantled, sandblasted and painted the compressor and developed the concept for the watering station plumbing and the layout. “They really took ownership of the project, and it would not have been the same without their ingenuity and expertise,” says Sincox.
The result is a watering station that’s easy to move and allowed the utility to recycle an old piece of equipment. Introduced in April 2015, the water wagon travels to community events around town. Team members connect the wagon to a water source and chill the water before serving it to the public. “One year, we included a water meter so we could measure how much water we put through it,” says Sincox.