Those 'Dig We Must' signs with which Con Edison used to vex New Yorkers won't be showing up around here although New Castle County is about to spend the next five to seven years rehabilitating the entire 1,500-mile sanitary sewer system. New technology will enable workers to both inspect and repair the pipes without pockmarking the landscape.

A wide area of northeastern Brandywine Hundred, served by what are known as the Delaware and the Naamans sewer lines, has been designated as the initial phase of the project. The territory drained by the lines forms an inverted 'L' along the Delaware River between Edgemoor and Claymont and west along Naamans Creek to roughly Shipley Road.

A web of terra cotta pipe, with diameters ranging from eight inches in the farthest reaches and growing to 30 inches,

carries between 10 million and 11 million gallons of effluent a day to the city of Wilmington's sewage treatment plant along the river just north of the city. That plant handles all sewage generated north of the Chesapeake & Delaware Canal.

Some work already is underway, according to project manager Ted DeBoda, but a concerted and focused effort to remedy many years of deferred maintenance was approved by County Council as part of the capital budget enacted this spring. In all, some $7 million will be spent over the past, present and next fiscal years.

A public meeting to detail what is about to happen will be held on July 19, beginning at 7:30 p.m., in Brandywine High School. The session will be jointly sponsored by the county, the Council of Civic Organizations of Brandywine Hundred, the Claymont Community Coalition and the Fox Point Association.

Ted DeBoda (right) points to the areas of Brandywine Hundred -- shaded in green and yellow -- where initial sewer rehabilitation will occur.

County workers Joe Paoli and Ken Miller (below) prepare a remote-controlled camera for insertion into a sewer line. Paoli (below, right) follows its progress through the line with a television monitor.

While county officials emphasize that the project will result in a minimum of disruption, that is not to say that residents won't notice that something is going on. Sure to attract attention will be the technique of pumping white smoke into the sewers to locate problems. If the smoke comes out at places where it is not supposed to be able to escape, that will indicate a break or a crack. It works pretty much the same way as immersing a flat tire into a tub of water and looking for bubbles.

But, according to DeBoda, county officials are at pains to assure the citizenry there is no cause for alarm. Chemicals in the smoke are certified non-toxic and dissipate quickly, he said. Even if the vapors come out inside houses, there will be no ill effect and their presence will alert the householder to the need to fix something -- like a faulty trap in a drain pipe.

For some folks, there will be a bit of a down side to the smoke's tell-tale function, however. When coupled with flow meters, it not only will detect flaws but also help locate clandestine hookups. It has long been known that sump pumps, so-called French drains and even downspouts from roofs have been improperly -- and illegally -- connected to sanitary sewers. That flow is supposed to go into the separate storm sewer system.

DeBoda said no one can estimate how much 'unauthorized diversion' is happening, but those in the business have reason to believe such practice is widespread. "A lot of people don't even realize it's illegal" and it is believed that a majority of the connections were made by original owners and even builders, he said.

At this point, he added, there has been no decision about what is going to happen when the connections are discovered. Purpose of the project is to upgrade the sewer system and catch up on the effects of many years of deferred maintenance and being able to spot encroachment is secondary to that. Chances are there will be an amnesty with ample time to voluntarily remedy the specific situations.

"A big part of what we hope to do is informational," De Boda said. Although sewers are literally a part of daily life, they understandably are taken for granted. Unless something goes wrong -- backups of raw sewage into homes during a storm, for instance -- few people realize that collective misuse can produce widespread consequences.

Besides the smoke, the job of finding and fixing flaws is accomplished by the use of remote-controlled television cameras. They move through the pipes on dollies beaming back a running picture to a console in a truck parked between manholes. When cracks are located, they are sealed by pumping grout into them, using the same dollies. More extensive breaks are repaired by threading a plastic liner through the pipe. In the event of severe damage, the ultimate solution is a liner which can be inflated to a point where it bursts the pipe and becomes the new pipe.

Also by remote control, the pipes can be cleaned. That, DeBoda explained, is a major goal of the project because, as would be expected, it increases the capacity of the system without having to lay bigger pipe. A recently completed cleaning under the development of Rolling Hills reduced flow levels from between 20 and 30 inches to less than 10 inches, That is equivalent to increasing capacity by more than double.

Posted on July 4, 2001

2001. All rights reserved.

Get more information about this topic

Read previous story: Aged and broken sewers to be fixed.
Go to the Office of Wastewater Management Web site





get this gear!