Haleyville sewer system getting a bit of a makeover

HALEYVILLE - A sewer rehabilitation project began in Haleyville last week that is meant to prevent settling of the pavement above sewer lines, among other things.
Requiring no digging, the project will include cleaning and testing certain sewer lines (on 15th Avenue, 25th Street and Highway 13 near the Lion’s Pride service station) for leaks and sealing any that are found.
Waste Water Department Superintendent Drew Thrasher said that most of the above streets would not need to be closed during this project. “Everything will be done out of a truck sitting right over a manhole,” he said, “so traffic flow will be normal,” except at times on 15th Avenue. The width of that street and the proximity of the manholes there to Highway 195 will require the road to be closed at times for the workers’ safety, Thrasher said.
He explained the process: “(A remotely controlled grout injector) will go (to a) joint and pressure test it.” The device uses a burst of air to pressure test the joint, measuring whether any air is able to escape. “If it fails the pressure test, then you inject the grout, seal it and move on to the next joint.”
“The primary reason (for the project) is to stop the infiltration of groundwater (into the waste water system and to stop) road settling,” Thrasher said. He said the project would also save the HWWSB some of the money it is currently spending to treat extra water, both ground water and run off from rainfall, that enters the waste water collection system, though this particular project would only seal the joints of perhaps a tenth of the system, if that much.
“As you drive around town, you see sewer ditch lines falling in. When these pipes were put in starting in the late ’20s, they didn’t have the option of backfilling a trench with stone the way we do today with modern technology,” Thrasher said, explaining how water infiltrates the system and causes road settling. “Over the years, as those joints start separating and the water pressure and ground pressure outside starts feeding into those cracks in that pipe, it’s pulling the sand and the fine materials out of those ditch lines and creating voids in the road.”
The sand and the groundwater enter the pipes because the external pressure on the pipes from the earth above them is greater than their internal pressures, which means that while outside material is forced in, there is little chance of the contents of the pipes leaking out.  
“Then that (sand and water) is being transferred to pump stations and we’re having to remove sand. (It causes) wear and tear on pumps; plus, you get the groundwater that comes to the plant that there’s no revenue to cover the cost of treating,” Thrasher continued. “By doing this project, we’re going to stop that.”
Thrasher provided the following numbers to illustrate how much extra water has to be treated because of water infiltration into the collection system. “(For) daily flow, we average between 450,000-500,000 gallons a day. When we get a heavy rain, our daily flow doubles. In dry seasons, we can see our flow get down to around 380,000-400,000 (gallons) a day.” That would mean that even in moderate conditions—not too dry but without heavy rains—approximately 50,000-120,000 extra gallons of water are having to be treated.
“When you’re dealing with a system that’s nearly a hundred years old (and) it’s old clay pipe, this is the kind of problems you have,” Thrasher noted. “(When) you don’t have a customer base large enough to generate enough revenue to cover repairs on everything there is (to do), you have to do bits and pieces as you can.”