As the impacts of climate change intensify, many communities across North America are having to find new ways to stake claim on a precious commodity: clean drinking water.
Studies conducted in the past decade have revealed that wells and other water sources around the United States are testing positive for per- and polyfluoroalkyl substances, also known as PFAS, a group of highly regulated man-made chemicals often referred to as “forever chemicals.” PFAS has been used to make household items such as non-stick pans and raincoats since the 1940s. These chemicals are nearly impossible to break down and can linger in the environment for centuries. PFAS has also been tied to a long list of serious health conditions, which is why municipalities are actively working to remove the chemicals from their water sources.
Through innovative engineering and a community-focused approach, PCL’s Civil Infrastructure division recently set out to build an advanced water filtration facility on a well that not only provides a safe source of drinking water but offers the surrounding community a pathway to self-sufficiency in a time when water rights disputes are becoming more common.
“PFAS is found in air, water, and soil. All three elements are involved. It's not just the U.S., it's everywhere,” says Anup Patel, the PCL project manager overseeing the recent well rehabilitation project. “As a society, if we want to protect animals, humans, and the environment, then we have to remove PFAS from the water.”
A previously shuttered well that tested positive for PFAS is at the center of PCL’s current project. Local government officials, with a focus on ensuring long-term water access for the community, wondered if there could be a way to filter out the PFAS and make it safe to drink? If the well could be rehabilitated, it could provide a new source of drinking water for at least 700 houses, improving water quality for the community as a whole.
There are many proven methods for water filtration, but settling on the right one that would benefit the community and space required an adaptable project plan. This is why Darren Wright, construction risk manager for PCL Civil, says having a progressive design-build approach has been critical to the project’s success.
In the progressive design-build model (unlike the traditional design-bid-build approach where a contractor builds from a finalized design) the engineer, project owner and contractor collaborate from the project's outset to develop the plan.
“It’s collaboration at its finest,” Wright says. “Ultimately you know what needs to be done – in this case that a well needs to be rehabilitated – but the client doesn’t have to pay for investigative work for a precise design that may have to be changed later. Instead, the engineer is working directly with the contractor and collaborating as the job progresses, making decisions based on the site conditions.”
An important decision resulting from the progressive design-build delivery model was the water filtration method for the rehabilitated well.
“The wellhead is in a community of homes and adjacent to a park,” Patel says. “We needed technology that fit inside the area and would work with the amount of land we had available. If we went with technology such as GAC (carbon filtration), the city would have to purchase more land, which may have disrupted the park next to the project.”
This served as extra motivation to ensure the facility became a community point of pride, not an eyesore.
“With progressive-design-build, the contractor can make decisions in the field, and it’s easy to create a design because there are no unknown obstacles,” Patel says. “If the new design is approved, we’re able to quickly mobilize in the field and meet a fast timeline. It saves time and effort.”
Ultimately the project team landed on the deionization filtration method, which Patel explains is extremely effective but requires higher maintenance and smaller tanks than other methods, helping the neighborhood to maintain its curb appeal.
A chemistry refresher to understand how deionization works: An atom with an electrical charge is called an ion. Positive charges attract negative charges, and vice versa. In the case of using deionization for water purification, a tank is filled with a positively charged resin material that closely resembles amber beads. As water flows through the tank, the negatively charged PFAS chemicals attach themselves to the positively charged resin, releasing hydrogen in the process. Good ole’ H2O, now purified, flows back into the community.
The rehabilitation of this well is intended to enhance the quality of life in the neighborhood. With this mission in mind, PCL strived to be a good neighbor on the job site, working with the community to minimize disruption as much as possible.
There was one point in the project when concrete needed to be poured at 5:00 a.m. Patel knew how important the timing of the pour was to the project, but also wanted to prioritize the needs of sleeping neighbors. In the days leading up to the pour, he personally knocked on doors throughout the neighborhood to offer residents a chance to express their concerns regarding the timing.
“Everyone was very understanding of the importance of us working early in the morning, they said ‘don’t worry about us, you are here working for the community,’” Patel recalls.
With a decade of experience in water infrastructure construction, Patel says this well will always hold special significance, both as his first PFAS removal project and for the opportunity to provide a community with drinkable water.
“Water is essential for every daily routine,” Patel says. “Even plants need water, and the plants give us oxygen back. Water is literally as important as breathing. That's why this project means a lot because through me, through PCL, we are helping the community and the neighborhood.”