CHJA expansion necessary to allow growth
CHJA plant expansion year behind schedule
A major sewerage expansion is proposed for the Canonsburg-Houston Joint Authority.
Katie Roupe / Observer-Reporter
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In less than 15 years, the population in the Canonsburg-Houston Joint Authority’s service area is projected to exceed the capacity of its sewer plant. The wastewater treatment plant in Canonsburg, which services North Strabane, Cecil and Chartiers townships, as well as Canonsburg and Houston boroughs, needs to expand to accommodate the anticipated population boom.
The expansion plan – perhaps the largest in the plant’s history – already has been approved by the state Department of Environmental Protection, but its implementation is one year behind schedule. The authority and Canonsburg Borough are still discussing options for financing the project, which could cost around $25 million.
Within the authority’s service area, the population is predicted to nearly double by 2028, from about 30,300 people to more than 56,300. This growth is expected primarily in North Strabane, Cecil and Chartiers townships. While each municipality owns and operates the sanitary sewer system in its area, the authority owns the collection sewers, in addition to the Brush Run interceptor in Canonsburg and the Chartiers Creek interceptor in Houston. It also owns the main sewage pumping station in North Strabane and the wet-weather pump station in Houston. The authority owns the wastewater treatment plant, but leases operations back to Canonsburg Borough, which is in charge of its day-to-day operations.
In order to comply with the DEP’s preliminary effluent limits, the authority must expand in accordance with the DEP’s Act 537. The 2006 update on the “Sewage Facilities Plan” requires “that every municipality within the Commonwealth develop and maintain an up-to-date sewage facilities plan.” The plan calls for upgrades and expansions in two phases, the first of which optimizes the treatment process and corrects hydraulic problems, which already has been completed by the authority.
Phase two of the project will expand and upgrade the facilities so the plant can handle an ultimate flow of 8.4 million gallons per day, an increase from its 3 million gallons per day in 2008. The plan also includes provisions for the expansion of the wet-weather pump station from 2 million to 4 million gallons per day and the construction of a new pump station on the authority’s Canonsburg property.
Currently, the sanitary sewers from Southpointe enter the treatment plant by gravity, while all other flows are pumped to the plant. This creates hydraulic problems, so a new pump station was proposed “to lift the Southpointe flows to a suitable elevation to eliminate the hydraulic problem,” according to the DEP’s plan update.
Dan Goodwin of Wade Trim, the lead design firm on the expansion project, said Southpointe is expected to have a great deal of growth over the next decade.
“Southpointe obviously is one of the areas that’s targeted to be developed quite a bit over the next however many years, so the plant would be anticipating quite a bit of flow coming from that area in the future,” Goodwin said.
Additionally, the authority will construct an odor-control mechanism, new primary clarifiers and a headworks facility, which removes large debris and grit when flows enter the plant, Goodwin said.
“I don’t think anything has been done since the original treatment plant was constructed that would be of this magnitude in terms of an upgrade,” Goodwin said.
Katherine Gilmartin, manager of the authority, said the expansions will take place in a contained area on the authority’s Canonsburg property.
“This plant, from my understanding, is unusual because the authority owns a lot of land … (so) it was easier for design that way because you weren’t trying to retrofit things in a tight space,” Gilmartin said.
Shawn Rosensteel of Chester Engineers said the authority is currently under a tap restriction by the DEP, which limits the number of taps that can be purchased each year and causes “a big headache” for developers. He said the impact of the expansion project would be positive for residents and prospective developers.
“Once the plant is expanded, it’s our understanding the DEP will consider the lifting of the tap restrictions, and that would allow growth to happen … as it normally would,” Rosensteel said. “It wouldn’t have to be planned so much to fall within the amount of taps that are allotted every year. … It would allow growth to happen as it would elsewhere, without restriction.”
Rosensteel said the project will likely be three years behind schedule by the time it is completed, but the authority is ready to begin construction as soon as finances are secured. The opening of bids for the project has been delayed, but it is expected to occur in January.