News

August 3, 2004

Repairing and upgrading the county's sanitary sewer system in Brandywine Hundred has turned out to be a "bigger, more complex and more technically challenging" job than the much-talked-about extension of the system to the area south of the Chesapeake & Delaware Canal, according to David Hofer, assistant county engineer.

And it will be considerably more expensive.

The tentative price tag is $190 million. Actual cost over the next six years is likely to range somewhere between $170 million and $220 million. And that is in '2004 dollars', unadjusted for inflation.

Hofer said he cannot equate what that with what it will mean in increased sewer fees which every householder in the county pays because County Council has not yet determined how to finance the overall job.

By way of comparison, however, the estimated cost of extending sewers to about a third of the southern area is about $80 million. That will be paid by property owners, developers and eventually

score has about tripled since the project was conceived in 2000, Hofer said.

At least 30% of the piping system is "in need of [rehabilitation] due to excessive leakage or structural failure" during the next six years, according to the presentation the officials gave to Council. An additional 20% will require such work in five to 20 years. Moreover, as many as one in every 10 houses

have illegal sump pumps attached to the sanitary system and one in 20 have 'French drains'; that is, basement drains illegally tapping into the system,

There are 2.2 million feet of sanitary sewer in Brandywine Hundred and another 500,000 feet connecting individual houses to the system.

The first major projects will begin with advertising for bids on one by the end of August and the second before the end of the year. Considered demonstration projects, these are centered on Brandywood and developments around the Silverside-Shipley Roads intersection.

In all, 40 'first priority projects' have been identified in the part of the system that parallels Naamans Creek and 30 in the part paralleling Shellpot Creek. They make up the first phase of the overall project, which has a $110 million price tag and a 2010 target for completion.

In addition to having committed to correcting problems which are said to have resulted, in large part, from lack of adequate maintenance over the years, the county also agreed last October with the state secretary of natural resources to do away with the two remaining combined sewer overflows. Those are pipes at the mouths of Naamans and Shellpot Creeks which carry both storm and sanitary sewage into the Delaware River when the flow exceeds capacity to handle and treat it. There originally were six overflows, but four were removed in the mid-1970s.

The agreement is the subject of a 'conciliation order' by the secretary to eliminate the remaining overflows and to spend at least $9 million by December, 2005, to rebuild the pump station at Stoney Creek, repair manholes and undertake other projects required to prevent any raw sewage from entering the river.

The county voluntarily brought the situation to the attention of the Department of Natural Resources & Environmental Control, Hofer said. "We are trying to be proactive and solve problems. ... You don't ignore something that affects the environment," he said.

Environmental regulation contributed to one of the top-priority projects on the list. Concrete pipe which makes up a major interceptor line along the river is heavily corroded and expected to fail within five years. Hofer explained that the pipe has been eaten away by sulfur, which is a significant component of residential sewage. Federal environmental legislation several years ago required industrial plants to eliminate metal salts from their discharges. In the past, those salts reacted chemically with the sulfur, which eliminated the corrosive agent.

That pipe, he said, "should have lasted 50 to 100 years, but is [now] expected to fail after about 30."

If the county has been willing to 'fess up, with the state, it expects homeowners to do the same with the county. Those who voluntarily come forward and admit to having illegal connections to sanitary sewers will qualify to either have them removed at county expense or be given an 'amnesty letter' which will excuse them from having to remove them before the house could be sold.

About 400 property owners have done so since the amnesty was announced two years ago. Hofer said there is as yet no end date for participating and it will be widely publicized in community meetings and the like in neighborhoods where there are rehabilitation projects.

Hofer said it has not yet been determined what the cost of doing the replacement work will be. A pilot program to remove illegal connections or redirect their flow into the storm sewer will involve about two dozen houses in Beacon Hill. The intent, he said, is to come up with a standard cost-benefit assessment to determine which pumps and drains are worth removing and which will be allowed to remain with the property owner absolved from future liability.

On the other hand, the cleaning out and repairing of pipes during the various projects will include, where necessary, lateral pipes which connect individual houses with the system. Normally that is considered a property owner's responsibility. Again, Hofer said, he is not able to give a cost estimate since the work will be included as part of the overall rehabilitation contract. But, he added, a plumber would charge about $3,000 for a typical lateral replacement.

The sewer system consists of four components. Hofer's explanation: The lateral line of 4 in. to 6 in. diameter pipe is equivalent to a driveway. The 8 in. development sewer would be the equivalent of a community street. Next come trunk lines, with pipes ranging from 10 in. to 18 in., which compare with highways. Finally there are interceptors ranging from 24 in. up to 72 in. in diameter, which are the 'interstate highways' of the system.

While the situation could be characterized as alarming, Hofer said there are some upbeat aspects.

The exploratory work found that about half of the Brandywine Hundred system -- parts of which date back to the 1940s -- is functioning without need for rehabilitation. Interestingly enough, it would appear from a map of the primary- and secondary-priority projects that the older suburbs in the southeast quadrant of the hundred are in relatively better shape.

Then, too, present-day technology makes it possible for much of the remedial work to be done rather unobtrusively. No longer, in most instances, is it necessary to dig long trenches to remove old pipe and install new, Hofer said. Instead, new high-density polyethylene pipe can be threaded as an impervious liner into existing damaged and leaking pipes. In instances where the damage is severe, a fiberglass liner with uncured resin can be inserted. When the resin is heated, the liner inflates and bursts the old pipe, which still retains some of its structural support.

Hofer said the new piping will be considerably more enduring than its clay and concrete ancestors. "We expect it to last a minimum of 50 years without any corrosion or much damage," he said.

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