Treatment plant should be on line second week of September
Final construction continues on the 1.86 acre facility located off Connellsville Street. Merit Construction of Monongahela has been building the plant.
In preparation for the start-up, the two 150,000 gallon aeration tanks were filled with Dunbar Creek water, which was treated like sewage: aerated, then passed to a sludge holding tank and finally disinfected by special ultraviolet (UV) lights before being sent back into the creek.
Sewage treatment at the facility is a four-phase process, according to Don Reho of Widmer Engineering.
Raw sewage arrives at the plant and is separated by a mechanical screen that removes large solids, like sanitary products, that might otherwise clog the system. These solids are deposited in a wrapped trash bin and taken to a landfill approved to receive sewage.
'The second phase involves two aeration tanks, in which the sewage receives biological treatment,' said Reho. Each tank is 17 1/2 feet deep and 41 feet in diameter. 'The sewage is eaten by microorganisms naturally occurring in the sewage. The microorganisms are kept alive by aeration, provided by pumping air through large rubber tubes. The ones that die become sludge that you get rid of by pumping into a sludge holding tank.' The aeration will also prevent odors and mosquitoes.
The remaining liquid will be pumped to a disinfecting unit.
'The UV system is the latest technology that disinfects the liquid waste non-chemically,' said project inspector Steve Eby of Widmer Engineering, Connellsville.
'The UV lights are designed specifically for sewage treatment facilities. They kill bacteria and viruses. The water discharged into Dunbar Creek will be clear. It's not suitable for drinking but not harmful to anything in the stream,' said Reho.
The plant operators, H&H Water Controls of Carmichaels, will test the discharge every two days and send monthly reports to the Department of Environmental Protection to verify that the plant meets effluent requirements. Additionally, the plant must receive yearly operating permits from the DEP, said Reho.
The solid waste, consisting of dead microorganisms, will be pumped from the sludge holding tank to a belt filter press inside the plant building. 'The press dries the sludge which is transferred to a wrapped Dumpster and taken to a landfill which handles sewage,' Reho said.
The plant, capable of processing 300,000 gallons of sewage daily, is virtually automatic. Operators will be responsible for monitoring water discharged into the creek and ensuring that all equipment runs properly.
'We allow at least 25 percent reserve capacity for new construction,' said Reho. The project currently includes about 950 taps.
The total project cost $6.5 million; the treatment plant and pump station cost $1,790,544, according to Reho. The authority received $2,204,000 in grants and a loan of $4,304,300 for the project. The loan will run for 40 years.
Users pay a $900 tap-in fee and $38 monthly once the project is operational. 'People are concerned about the cost, but the Rural Utility Service (a division of the USDA) set up the numbers and in Dunbar, houses are far apart and there are lots of state roads, which adds to the cost of laying pipe. The borough was notified years ago that they've got to clean up the environment. If this project had gone in 40 years ago, it'd be paid for,' said Eby.
'There's only so much grant money. They give you what they can. I am really amazed at the number of people who support the project. About 63 percent of the residents have paid their tap-in fee. I think we've got it geared to hold the line on taps and monthly rates. I'm concerned with getting this project up and running and serving the customers,' said Anthony Tristani, authority chairman.
'We have tried to do more for the borough than just bring sewage,' said Eby. 'We've put curbs in and inlets for drainage on borough roads to help with street drainage problems. Some of the roads hadn't been paved in years. People have been pretty patient considering the size of the project. We're not done working or reconstructing yet.'
An additional benefit may appear as the creek recovers from years of illegal sewage discharge.
'It will take years to get the existing raw sewage flushed out of Dunbar Creek, but as that happens, the creek may become the kind of trout stream it used to be,' said Tristani. 'I remember when the state police had to come to keep the roads clear on the first day of trout season. It could happen again.'