A focus on constant improvement helps an Illinois water plant earn 15 straight Director’s Awards from the Partnership for Safe Water.
It just keeps getting better.
That’s the watchword at the Pontiac (Illinois) Water Treatment Plant after it received a Director’s Award of Recognition from the Partnership for Safe Water for maintaining Phase III certification for 15 consecutive years.
From clarification, filtration and disinfection to chemical feed, turbidity reduction, nitrate removal, source water protection and more, the improvements never stop at this 4.0 mgd (design) facility, which dates to 1893 and has been operated by Illinois American Water and its predecessors for more than a century.
Tim Tuley, operations superintendent, who has been at the plant for 39 years, says a drought in 1988, a flood in 2008, and algae in the source water led Pontiac to make improvements.
Operators provide critical input to the enhancements. “They have input into what changes we make,” says Tuley. “If they have an idea or thought, we talk to our engineering group and decide if it’s something that would be a benefit. We listen to them all the time.”
Surface water challenges
The Pontiac plant draws most of its water from the Vermilion River, but also from a 325-acre abandoned quarry that serves as a surface water reservoir. Since Pontiac lies in an intensely farmed area, nitrates can pose a problem. When nitrate levels increase in the river (usually from December to July), the river water is blended with water from the impoundment to help ensure quality and meet state nitrate standards.
First, the raw impoundment and river water can be treated with powdered activated carbon to improve taste and odor. Then, once it reaches the plant, the water passes through one of three piping loops to achieve mixing of the carbon and extend detention time. The culprit is seasonal changes in the water-like algae. “The river is constantly changing, so we need to keep an eye on it, especially in the summer,” Tuley says.
The plant’s clarification system consists of four 1 mgd rapid-mix upflow clarifier trains. In one train, a circular Ovivo unit does the work, while the other three Permutit Precipitator units (Evoqua Water Technologies) are cone shaped. The clarified water is dosed with fluoride and chlorine and with a cationic polymer that serves as a filter aid in the six steel tank dual-media sand and anthracite filters that follow. Underdrains are by LEEM Filtration.
After filtration, ammonia is added to convert the chlorine to chloramines. Then the flow is pumped to a 450,000-gallon dual-chambered baffled clearwell. The plant also houses a Tonka Water Pur-IX low-waste ion exchange system for nitrate removal. “It’s another option we have,” Tuley says. “In case of a raw water shortage, we can remove nitrates directly at the plant and save our reservoir water for backup.”
From the clearwell, the finished water flows by gravity back to the plant for distribution to customers. Pontiac maintains about 74 miles of water mains and a 500,000-gallon elevated storage tank.
Waste solids are pumped to a storage vault and then transferred to two lagoons alongside the reservoir. Several years ago, one of the lagoons was cleaned after 10 years and the settled solids were landfilled. In the future, there are plans to land-apply the solids.
A standard SCADA system controls and monitors the process and provides remote control of the small Saunemin well system nearby, which Illinois American Water also operates.
The central Illinois drought of 1988, which saw near zero precipitation during the summer and low flows in the Vermilion River, prompted Pontiac to acquire the abandoned quarry north of town for use as a supplementary water source. That kicked off a series of improvements in the water system, which Illinois American Water has continued. The plant was expanded to 4.0 mgd capacity in the early 1990s, and the third Permutit Precipitator upflow clarifier and the fifth and sixth filters were added.
In 2000, the Pontiac district installed the powdered activated carbon system and began work on the chemical feed systems. “We installed a permanent feed system for cationic polymer,” Tuley says. The enhancements included inline chemical feed calibration devices to improve feed accuracy.
“We also performed a number of coagulant studies, using particle counters and jar tests to learn as much as we could about controlling turbidity and keeping it as low as possible,” Tuley says. “We switched our coagulant to polyaluminum chloride and changed the way we operate our Ovivo upflow clarifier. It has helped lower our turbidity numbers going to the filters.”
The target for turbidity is less than 5 NTU, and the attack on algae continues. “Our goal has always been continuous improvement,” Tuley says. “We’re always looking for what we can do to get better results.
“In 2006, we started using a new copper sulfate pentahydrate product from Earth Science Laboratories called EARTHTEC in place of copper sulfate. We made the switch primarily to help eliminate copper from our waste solids. The product stays in suspension and doesn’t settle out like copper sulfate does. We want to reduce the copper content of our solids as we move to land application in the future. Environmentally speaking, it is the responsible thing to do.”
New chemical feed
Five years ago, Pontiac acquired land next to the plant and constructed a new chemical feed building for containment and storage of bulk chemicals to meet new regulations. The plant is actually in the floodplain, and the new building is situated on higher ground. “For safety reasons, we also made the switch to liquid chlorine,” Tuley says. “We still store our cationic polymer inside the main plant, but all other bulk chemicals are stored in the new building.”
In 2004, the plant, with the help of operations supervisor Kent Woodburn, installed PLCs and made changes to its filters, replacing electrically controlled valves with pneumatic valves. The change has helped keep the flow through the filters more consistent. “It’s a modulated flow instead of full-on or full-off,” Tuley says. “The valves open and close gradually as needed to maintain a constant flow.”
The team has also increased the effectiveness of filter backwashing by improving the surface wash spray system and — this year — installing a new backwash pump (Cornell Pump Company). “We’re also working on a project to fully automate the backwash system,” Tuley says.
The team has installed variable-frequency drives on all high-service pumps and now enjoys reduced electrical usage and a decrease in water hammer. “That has stopped the shocks,” Tuley says. “We’ve seen a significant reduction in main breaks in the distribution system.”
There have been changes at the reservoir as well. “In 2010, we installed ultrasonic algae control devices in the impoundment,” Tuley says. “In addition, we feed some copper sulfate. We also use an environmental contractor to treat the reservoir each fall to control the growth of Eurasian milfoil. The contractor also sprays to keep invasive phragmites from overgrowing along the banks.”
The road ahead
In the future, Tuley sees his team continuing to work on filter performance. The filter backwash automation project is designed to improve operations and reduce the amount of backwash water returned for further treatment.
“We’re also looking at adding tube settlers to the clarifiers, and another carbon feeder at the reservoir,” says Tuley. “We continue to seek better coagulants to help keep our turbidity low.”
It’s a continuous process of evaluating and contemplating changes that will make things better. Through it all, Tuley and American Water rely heavily on the ideas of his team members:
- Mark Weber, chief plant operator
- Corey Robinson, Nathan Schlosser, Steve Bright and Ryan Hoke, production technicians
- Bryan Beecher, distribution group foreman, and technicians Todd Miller, Greg McAllister, Steve Gray and Kevin Johnson
It’s a good bet that together, they’ll help Pontiac add more years of Phase III recognition.
The Pontiac Water Treatment Plant is active in the Vermilion River Watershed Task Force, a group of stakeholders formed in 1996 to promote awareness of the impact of excess nitrogen and phosphorus in the Vermilion River and its tributaries, and to seek solutions.
“We helped form the task force,” says Tim Tuley, operations superintendent. “The primary focus back then was to bring the nutrient issue to the forefront. We were trying to develop awareness, to get everybody in the whole community involved and get them to understand the issue of excess nutrients in the water.”
The task force involves landowners, vendors, water and wastewater groups, and farmers in the watershed. Surveys indicate that more than 85 percent of the 1,400-plus square miles in the seven-county watershed are used for crop production.
In 2015, Illinois American Water provided a $5,000 environmental grant to the Conservation Technology Information Center (CTIC) for projects focused on educating farmers about best practices. CTIC has created videos with the funds provided to showcase real-world success stories focused on various topics, including nutrient reduction.
The emphasis is on solving the problem through land-use best practices and end-of-pipe technologies at area treatment plants. Tuley says the focus is on how to reduce nutrients through water retention, tree planting and modern farming techniques that use GIS mapping to help farmers apply the appropriate amount of nitrogen fertilizers.