Sewer system upgrade work in Sheffield Township is nearly in the can.
Engineer for the project Al Vanderpoel of E&M Engineering in Bradford said both components of the project, an upgrade to the sewage treatment plant and an extension of the sewer system lines, are nearly finished.
"It is 70 percent complete," Vanderpoel said of the plant work. "We're projecting by about Nov. 15 it'll be functional."
The plant is estimated to be completely finished by December, meeting the Department of Environmental Protection's (DEP) January deadline.
The new treatment facility is an upgrade to the original plant built in 1962. The site has relied on an extended aeration method to process waste in which sewage is placed in one of two holding tanks and progressively broken down.
In traditional aeration treatment, sludge settles in a primary clarifier tank before biological treatment and movement to a secondary clarifier tank for aeration and then settles following treatment. Treated water is then released.
Both clarifiers produce waste sludge which must be treated and disposed of. The process moves incoming waste through two stages with no intermixing.
The upgraded facility will use a sequence batch reactor process in which waste is placed in one of two tanks to settle. At the same time, a second tank, with a common inlet, holds aerating waste. The two tanks share a waste water inlet which can be switched to flow from tank to tank. The flow switches between sides of the tank, mixing incoming waste with activated sludge which has already begun biological treatment. The process speeds treatment of waste in a biological digestion process. Essentially, incoming waste is diverted to a tank and mixed with activated sludge mechanically, without adding additional air. Aeration is then performed. Settling follows and treated water is released. The process breaks down approximately 95 percent of raw sewage, Vanderpoel said.
Remaining sludge after waste water treatment will be transferred to the site's original aeration tanks, which will be converted to reed beds to further break down sludge. Anything remaining must eventually be removed, but the reed bed extends the period before removal must occur.
Water in both systems enters a tank to be chlorinated before release.
"It's all computer operated, so the system can run essentially operator free. The system can notify an operator if necessary," Vanderpoel noted. "In probably ten to fifteen years we'll have to remove it (sludge from the reed bed). The technology is miles ahead of where it used to be."
As for the extension of township sewer system work on the main lines is nearly complete. The contractor will install laterals to properties and, where needed, grinder pumps.
"It's the residents' responsibility then to connect to the either the lateral or the grinder pump. It's essentially done. They're working on the laterals right now," Vanderpoel said. "The other work for the contractor is the restoration, fixing up roads and driveways mostly."
The extension stretches outward from the township's existing system along Route 6 towards Warren and in the opposite direction towards Kane, along Bull Hill Road and into the Barnes area.
The DEP deadline for the extension work is December of 2013.
Upgrades to the sewage treatment plant cost $4.25 million and sewer line extensions cost just over $3.5 million. Work is being paid for through a $2,256,712 PennVEST infrastructure grant and a $5,513,571 loan from PennVEST. The loan portion of the funding is financed at 1 percent interest over 20 years.