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Plugging sewer leaks a big task in Niskayuna

Sunday, September 30, 2012
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Niskayuna Water and Sewer Maintenance worker, Kevin Hart, gets ready to set up camera that will travel through sewer pipes on Hexam Rd. If there is a needed repair, the black metal container in the foreground injects a gel grout to fill cracks and holes.
Photographer: Marc Schultz
Niskayuna Water and Sewer Maintenance worker, Kevin Hart, gets ready to set up camera that will travel through sewer pipes on Hexam Rd. If there is a needed repair, the black metal container in the foreground injects a gel grout to fill cracks and holes.

— As the state Department of Transportation began work recently to resurface a section of Balltown Road, town Water and Sewer Superintendent Rich Pollock saw an opportunity to fix up four deteriorated manholes along that stretch, manholes that weren’t necessarily a hazard to traffic, but a hazard to the town’s sewer system.

Those manholes, along with countless other cracks and seams throughout the system, can let rainwater into a system that should be entirely self-contained.

The effort became part of the town’s larger effort to stem the flow — and sometimes the wave — of water into one of the town’s two sewer systems.

It’s a problem the town has battled for years, and one that two years ago resulted in the Department of Environmental Conservation imposing a building moratorium on the town until improvements are made. The plan is to bring the flows down to desired levels by 2015.

That moratorium hasn’t had material impact yet, town officials say. Projects that were already in the pipeline when the moratorium went into effect were grandfathered in. But future projects could be hampered.

To ensure that doesn’t happen, the town’s Water and Sewer Department has been working to find as many areas of “inflow and infiltration,” referred to as I & I, into the system as they can, then plug them and seal them.

The DEC has been pushing the town to fix the problem since a 2003 DEC order. In 2010, the DEC found the town in violation, leading to the agreed upon moratorium on new sewer hookups. That means no new building projects that require a hookup can be approved.

The town now provides regular updates to the DEC, charting progress its made and the techniques used. The most recent update was due Friday.

The problems come in with years of deteriorating infrastructure, incorrectly connected sump pumps and a general lack of attention to detail when the sewer pipes were initially laid years ago.

One method used to fix the problem is a grout truck, equipped with a movable camera and sealing system, called vehicles, that can move through the town’s sewer pipes allowing workers to find and seal cracks. The method allows workers to inspect pipes and seal cracks without digging or interrupting service. The town bought the truck for $400,000 in 2007.

Workers using that truck have been slowly going through the sewer district’s estimated 115 miles of sewer main, focusing first on older main made of terra cotta found generally in areas built before 1970.

The older main has joints that the sealing vehicle can pressure test. The vehicle is pulled down the sewer line. Areas that need to be sealed are then injected with a liquid sealant that hardens in seconds, essentially sealing the crack from the outside. The sealant is pushed through the cracks, staying liquid long enough to set up inside the crack and outside the pipe. If the repair passes another pressure test, the workers move on.

On one recent morning, the truck set up along Hexam Road, with workers inspecting and sealing the lines there. It’s an immense task.

“Each joint is 3 feet apart,” maintenance worker Kevin Hart said. “That’s a lot of joints.”

What has the DEC concerned is the high volumes of water sent to the town’s District 6 sewer plant, particularly after storms. The plant is built for 3 million gallons, but flow can swell to 9 million gallons on rainy days, town officials have said. While the water is always treated, Pollock notes, volume means the town can’t meet level of material removal that the DEC wants.

In a perfect system, Pollock said, a rainstorm should have no impact on the sanitary sewer flows.

The easiest approach to the problem, or at least the least publicly painful, has been to simply go through the system and plug up the holes and cracks, all the while providing the DEC with regular status updates.

“My take is, let’s focus as much effort as we can to eliminate the I & I in the collection system,” Pollock said.

It’s hard to gauge how much the effort is costing the town, officials said. The water and sewer problem has more workers than 10 years ago. They also have more equipment, like the grout truck purchased in 2007.

“We’ve got more people and more equipment that we’re throwing at the problem,” Pollock said. “Is that enough to fix it in five years?”

Pollock’s not sure it is. The town is also looking at improvements to the sewer plant infrastructure, namely adding a large tank or tanks to hold excess flows from storm events until the peak passes.

The tank approach was one of the recommendations from a consulting firm the town hired to look at the problem. The town voted to spend up to $50,000 on engineering and design work on that proposal this past spring.

There are other problems with the system, like some residential sump pumps that were inadvertently directed into the sanitary sewer system when the homes were built. But town officials have instead focused on the town lines.

The town has made moves to go after larger users, such as apartment complexes, if extra water is detected coming in from them.

Mapping the exact problem, though, has proved to be difficult. Newer pump stations, stations that help move the flow to the sewer plant, have meters to monitor how much is going through.

Older ones don’t have those, Pollock said. For those areas, the town has purchased portable flow meters. It is new meter data that the DEC sought in its report that was due Friday, according to DEC spokesman Rick Georgeson.

The overall goal of the department’s push, Georgeson said in a statement, is a simple one.

“DEC’s goal is to meet the requirements of the Clean Water Act so that the people of New York can enjoy our rivers and streams and take advantage of recreational opportunities across the entire state,” Georgeson said. “We will continue to work with municipalities to help them achieve these legal requirements.”

Gauging the problem caused by storms, and the spikes caused as a result, has proved difficult, Pollock said, especially with this past summer that was generally dry. If it doesn’t rain, the town can’t really get an indication on whether they’re making progress or not.

Even with rain, though, Pollock said, comparing different storms can be tough.

Flow data, with an accurate indication of how far the town has come, will become more important as new projects want to get approvals.

In those cases, the town would have to prove four gallons of wastewater were removed from the system for every one gallon they want to have allowed.

Pollock hasn’t been complaining so much with the lack of rain, though. With more rain, the water table gets higher and there’s more chance of water seeping into the system through those cracks. With that, the town hasn’t had the problem of the plant exceeding its capacity.

A storm did come on a Tuesday night earlier this month. That gave them some indication of where they stand, Pollock said. The flow spiked up, then quickly dropped off.

“If it had gone up more slowly, that would have told me that, OK, infiltration is a big issue,” Pollock said. “But if you see a really quick spike up and drop off, that’s telling me there’s more of an inflow issue. Somewhere, water is quickly getting in the system. When the rain stops, it drops right off and the problem goes away.”

Workers have targeted other manholes around town, especially those that run in low-lying areas, including a line that runs in a swampy area behind the Jewish Community Center. With those manholes, the workers have been putting special caps on them or, in the case of a line behind the JCC, building those manholes up so water can’t flow in.

Then there are the small cracks and breaks.

“We’re not finding huge leaks everywhere,” water and sewer engineer Matthew Yetto said as the workers worked on Hexam Road. “We’re just finding a lot of small ones.”

 
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