The project included a new headworks facility, the addition of primary clarification, expansion of the advanced water treatment (AWT) equalization, treatment, and pumping capacity, replacement of chlorine disinfection and ultraviolet disinfection, conversion of existing aerobic digesters to autothermal thermophilic aerobic digestion (ATAD), capacity upgrades to the dewatering facilities, and new primary plant power, metering, and distribution. “We were looking to see if we might be able to utilize different and better technologies to help us out,’’ Sansom said. “Six years is not typical. When we expand in a couple of years, we’ll probably go straight into design.” The overwhelming scope of the project was made more challenging by the requirement to maintain plant operations throughout construction. “You can’t just shut off a wastewater plant,’’ Sansom said. “When you have a community that’s still growing, people are still flushing toilets and using showers. It’s got to go somewhere. We really focused on keeping the existing plant operational and that required careful coordination between the contractor and our operations staff.” Multiple Water Sources Not all of Parker’s residents are served by the Parker Water & Sanitation District. PWSD serves about 20,110 accounts and anticipates serving 35,000 by 2040. It relies on multiple water sources to meet the community’s demand. Its resources include the Water Infrastructure & Supply Efficiency (WISE) partnership, Cherry Creek, Newlin Gulch and the Denver Basin Aquifer. PWSD pulls water from those sources depending on the season, daily water demand and drought conditions. The Rueter-Hess Reservoir, which was completed in 2012, encompasses 1,170 acres and is a key element in solving Parker’s long-term goal of reaching 75 percent renewable water supply for the community. The reservoir has a capacity of 75,000 acre feet and is a water resource for PWSD, partner districts, residents of Douglas County and the residents of the Colorado Front Range. The Rueter- Hess Water Purification facility treats up to 10 million gallons of water per day from the reservoir. The North and South Water Reclamation Facilities use the highest standards of advanced wastewater treatment to filter, treat and clean water to meet and exceed federal clean water standards. The treated water is discharged into Cherry Creek and/or transported to Rueter- Hess Reservoir. “We have very strict discharge requirements,’’ Sansom said. “It’s not direct potable reuse. It’s more an indirect potable reuse. We have very low nitrogen and phosphorous requirements that we have to meet.” Accessing Equipment Workers need to access equipment at the facility for maintenance and replacement, and Garney installed 10 roof hatches manufactured by BILCO for the reclamation facility. “We’ve been using BILCO hatches in existing buildings throughout the District,’’ Sansom said. “We haven’t had problems with the bulk of the hatches in the past. So why change something if it’s already working?
It makes it easier on operations and maintenance when we’ve got the same equipment throughout the district.” BILCO hatches are frequently used in projects related to wastewater management. The hatches are corrosion resistant and feature easy, one- hand operation. Dalco Industries, BILCO’s representative in Colorado, provided the doors for Garney. “We’ve found the BILCO hatches work well,’’ Sansom said. “The corrosion resistance is great, and we haven’t had any issues with them on this or in previous projects. As much as we can we like to remain working with the same manufacturer.” Nationwide Problem While Parker took steps to improve its infrastructure, the United States as a whole faces serious issues with wastewater management. The report card in 2021 gave the US an overall grade of D+ for wastewater infrastructure. There are more than 16,000 wastewater treatment plants, and 81 percent are at their design capacity. Another 15 percent have exceeded it, the report said. In 2019, according to the report, the total capital spending on water infrastructure was approximately $48 billion. The capital investment needs, however, were $129 billion. “This underscores a chronic trend of underinvestment in critical water-related infrastructure – drinking and wastewater systems,’’ the report said. “With this gap, only 37 percent of the nation’s total water infrastructure capital needs were met. Assuming that water and wastewater sectors continue along the same path, the total gap will grow to more than $434 billion by 2029.” Parker still faces challenges ahead in terms of infrastructure improvements. The community 25 miles southeast of Denver continues its unabated growth, and there are no signs of it slowing any time soon. “We are about 60 percent built out, and we anticipate that build out being done by 2040,’’ Sansom said. “That’s not actually that far away in the grand scheme of things. We know because of that growth, we’re always looking ahead to that next big project to make sure we’re delivering adequate water and wastewater services.” Infrastructure improvements require significant investment, but also require intelligent planning. In that regard, Parker is ahead of many other communities. “Our vision is sustaining life for our community,’’ Sansom said. “We provide water services, and we treat wastewater and that’s the kind of lifeblood that every community has to have. As employees, we’re really motivated by that vision, and we work hard to achieve that every day.”
Thomas Renner writes on building, construction, engineering and other trade industry topics for publications throughout the United States.
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December 2023 csengineermag.com
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