The City of Yorkton’s slogan is “Where good things happen.” Many happen at the new Queen Street Water Treatment Plant. Commissioned in 2012 and situated on Logan Green, the plant is part of a green water management system that incorporates the latest treatment technologies and green methods of handling filter backwash water.

In 2004, when leaders of this Saskatchewan city of 20,000 began working on a plan to upgrade aging water treatment plants, they started with customers. A survey asked residents what water-quality improvements they wanted and how much they were willing to pay.

Involving customers was a key to success. “We made the community aware that we wanted to build this new plant and we needed their input,” says Michael Buchholzer, director of environmental services. “We sent out the survey, held an open house and invited the public. The information we gathered helped us build the framework for the waterworks system.”

The system is a unique solution for this environmentally sensitive area, designated as such because of the shallow aquifer below. The city saved about $3.7 million by using settling ponds to treat the backwash water instead of diverting it to the water pollution control plant.

The system also includes wetlands for advanced treatment and wildlife habitat, stormwater management, aquifer recharge, multiuse sports fields and cycling and walking paths. The city won a 2013 Utility Excellence Award for innovative technologies from the Canadian Water & Wastewater Association, and the Logan Green Water Management System won four awards for innovation and sustainability that same year:

• Federation of Canadian Municipalities Sustainable Communities Award
• Canadian Association of Municipal Administrators Willis Award for Innovation
• Association of Professional Engineers and Geoscientists of Saskatchewan Environmental Excellence Award
• Saskatchewan Municipal Award for Excellence

Aging plants

With three antiquated water treatment plants, Yorkton clearly needed a new plant. “None of the plants were connected to each other or to all 14 wells,” says Glenda Holmes, waterworks manager. “We needed a new, high-output treatment facility. Our new facility is more than twice the capacity of our old system.”

Buchholzer says, “The older plants weren’t designed to remove manganese, so we modified the process through chemical addition to try to oxidize and capture the manganese on the pressure filters. The process was somewhat successful, but we still had numerous water-quality issues and complaints from residents about discolored water.”

Water hardness was also an issue. “During our residential survey, 43 percent said they would like the city to soften the water, and 43 percent said they would not,” says Buchholzer. “Only 27 percent said they would be willing to pay extra for softer water; 81 percent of those said they would only be willing to pay an extra $5 to $10 a month.

“We let the community know that in-home softeners would soften the water to hardness of 15-50 ppm of CaCO3, whereas the plant would soften to 150-200 ppm of CaCO3 for $11 a month. Thus, in-home treatment would be more efficient and could be used or directed where required.”

The city hired Associated Engineering as the consultant for Logan Green Water Management System and held a workshop to create the water system development plan. In 2006 the city began constructing a 4-million-gallon reservoir. The Logan Green project was completed in fall 2013.

Decreasing costs

Today the Queen Street plant can treat 5.8 mgd. At $33 million, it was the largest municipal project in Yorkton’s history, yet it cost one-third as much as a conventional backwash water treatment system.

Savings from the backwash filter treatment system are expected to be $3.7 million in capital and $6.3 million in operation costs, based on a 30-year plant life expectancy. Consolidating the water supply system to one location dramatically reduced heating and energy costs, travel time and fuel consumption.

Two of the old plants and a summer seasonal plant were decommissioned, and the third old plant was converted to a pumping station. “The existing 1.5-million-gallon reservoir was in good condition and required minimal upgrading,” says Buchholzer. Excess earth excavated for the new reservoir, water treatment plant and settling ponds was used to construct six multipurpose sports fields west of the treatment plant.

Raw water is aerated (Evoqua Water Technologies) to oxidize iron and manganese, and chlorine is added to further remove manganese and act as a disinfectant. Potassium permanganate is added to aid in oxidation and recharge the manganese greensand filters.

As the water slowly moves through a series of concrete tanks, the oxygen, along with the chlorine and potassium permanganate, react with the iron and manganese. After a two-hour detention time the water is passed through upflow roughing filters and then to greensand gravity filters (28 inches of greensand on 20 inches of anthracite atop a Leopold underdrain).

About 260,000 gpd of filter backwash water is sent to a backwash pit, then immediately pumped to outside sedimentation ponds. From there the water flows into a linear wetland, fishpond and infiltration pond. The entire process, including the 14 wells, is automated with an Allen/Bradley/Wonderware SCADA system (Rockwell) that allows continuous monitoring and immediate response to changes in water quality.

Automated plant

A team of seven operators had a hand in designing the new plant and was encouraged to visit it during construction to get familiar with the design. “We discussed design concepts, equipment and filtration systems,” says Buchholzer. “The operators chose aeration equipment and open gravity filters, which allow for visual inspection of the filter media.”

Learning the SCADA system was a bit of a challenge, says Holmes. “The old plants were manually operated, but since we had an older SCADA system at the wastewater treatment plant it didn’t take the staff long to become familiar with the capabilities of the water plant SCADA system.”

Stepping up

Besides operating and maintaining the water treatment plant, the operators run the 6.3 mgd H.M. Bailey Water Pollution Control Plant, a semiautomated secondary treatment facility 4.5 miles from the water plant. Operators perform lab work at both plants and maintain the wells, water tower, pumping station, settling ponds and lift station.

“They also prepare and review safe work practices and procedures and work as a group on problem-solving,” says Holmes. “All operators are engaged in their work and will step forward when needed. They put in extra time and participate in plant tours for schools, universities and service groups.”

Their greatest challenge is running separate water and wastewater facilities with different certifications. “We expect them to operate both plants and rotate back and forth,” Holmes says. “They have to know both equally well and keep up their certifications in both. We are always looking for new learning opportunities and are open to any classes the operators may find interesting and beneficial. We encourage them to obtain the highest certification possible and we cover the cost of courses and time to attend.”

The 23-year-old water pollution control plant was advanced when it was built. Some of the plant’s seven buildings are connected by tunnels that house equipment and utility lines. One building houses boilers that heat the facility with methane produced from anaerobic digestion. Biosolids are used for farm fertilizer or in the city’s large-scale composting program at the sanitary landfill.

“With more stringent federal wastewater regulations being proposed for 2015, the wastewater plant will need upgrading,” says Buchholzer. “Although we could probably use some of the existing equipment, we would have to go to nutrient removal.”

Future challenges

Buchholzer says the city’s greatest future challenge is protecting the aquifer. “We’re trying to increase public awareness of the nature and value of local groundwater sources by showing the link between an aquifer and a community’s drinking water supply,” he says. “The realization that drinking water comes from a vulnerable underground supply can lead to increased interest in protection measures.”

Another challenge will be finding and retaining qualified operators. “They have to have four years of post-secondary education equivalent to a college or university degree for this position,” Buchholzer says. “We start them at the lowest level and train them in hopes they will stay. While most have stayed [see sidebar], some have retired and a few have left for better wages.”

Buchholzer says the staff enjoys operating a plant that can produce such a high-quality product (0.110 NTU turbidity, 1.59 ppm total chlorine, 0.020 ppm iron, 0.021 ppm manganese). “Our final objective is to work with the Saskatchewan and Yorkton Wildlife Federations to stock our final settling pond with rainbow trout,” he says. “Its park-like setting allows residents to relax, get back in touch with nature and remove themselves from the city environment.”