Kent plans array of sewer system projects in 2018

DOVER — Heading into 2018 the Kent County sewer system will leave a troublesome year behind it.

Twice this year, DNREC had to suspend shellfish harvest in the Delaware Bay and inland rivers because of unacceptable releases from the sewer system — one resulting from a spill of raw sewage in Dover and the other from a treatment plant malfunction expelling “undertreated” wastewater.

The two incidents aside, the county’s sewer system is pitted against rising wastewater volume and an aging — and crumbling in some areas — infrastructure.

Both issues have since been addressed and the county’s public works department is currently meeting its DNREC-set obligations.

Acting director of the public works department, Diana Golt, stepped up a few months ago to replace former director Andrew Jakubowitch who accepted a new position at Century Engineering Inc. in Dover.

Although Ms. Golt recently stepped into the position, the Delaware native is no stranger to the county’s sewer operation. She’s been with the department for about 19 years, even serving a brief stint as acting director once before back in the early 2000s.

Despite the challenges ahead, Ms. Golt points to a dizzying array of projects in progress and soon-to-start that she believes will not only address potential problem areas, but update infrastructure and prepare the county’s system for the future.

Spill at Legislative Hall

In early February, complications associated with emergency repair work on a broken 30-inch concrete sewer line caused an estimated 300,000 gallons of raw sewage to be spilled into the Saint Jones River in Dover. The leak took place at the county’s pump station #3, located on Water Street just south of Legislative Hall.

At the time, a reader of this paper comically noted that “sewage spewing from Leg Hall is business as usual.” However, the spill was serious enough that DNREC issued an emergency order that suspended commercial and recreational shellfish harvest of oysters, clams and mussels in the Delaware Bay. The harvest closure was in effect for about 21 days.

At the time, Michael Bott, an environmental scientist with DNREC, said that this is the federal standard suspension, but considering the amount of “flow” the Saint Jones River and Delaware Bay saw from the spill, it’s a generous amount of time.

“In systems like the Delaware Bay and the Saint Jones River, raw sewage is going to dilute and flush out fairly quickly,” he said. “A week or two afterward you won’t detect it in the water column. There aren’t any long term affects to the wildlife in the area and the Delaware Bay that are anticipated.”

He said suspending “filter feeder” harvest for that duration of time is important though because they can “bioaccumulate” hazardous material found in the water column for certain periods of time.

The spill was indicative of a more widespread aging infrastructure issue the county’s sewer system is facing, as it came while the public works department was in the middle of trying to repair a leaky line. Work crews were in the process of addressing an emergency transmission line break near Postlethwait Middle School. Since the line was underneath a road, the county determined that the best way to repair it was using a method called slip-lining. With this repair, a smaller pipe is slipped inside the damaged pipe to block the break. The repair is considered a “long-term” fix.

During the process of this particular repair, public works needed to interrupt the sewage flow through the line at certain points to continue work. This was done by closing several valves at their upstream pump stations. As a result of closing the valve at pump station #3, there were “operational issues” that ultimately cause the sewage spill.

Ms. Golt said that many of the transmission line in this part of Dover are concrete pipes that date back to the 1970s. Although this doesn’t automatically mean that they need replacement, some may be nearing an unacceptable level of deterioration.

“It depends on what sort of wastewater has been going through the pipe and whether or not the release valves have been maintained over the years to relieve gases that build up that can speed deterioration,” said Ms. Golt. “You may also have soil conditions around the outside of the pipe that affect its rate of aging.”

Because they can’t be sure which pipe may need urgent attention, the public works department is nearing the action phase of a system-wide assessment project.

“We’ve completed interviews and will make a selection this month for engineering services on our pipeline condition assessment project,” said Ms. Golt. “We’ll focus on our gravity and force main systems. It’ll be a desktop analysis trying to identify low hanging fruit type projects we can address immediately. We’ll also be looking at how to address the issues. Just because you find a problem area doesn’t mean it’s going to be easy to fix. Some pipes can be slip-lined, but for others it may be best to run a parallel pipe if there is room.”

U.S. 13 sewer main project

One such notoriously hard-to-reach sewer line is the concrete force main that lies underneath the median of Rt. 13 running through Dover. The line developed a crack several years ago to the extent that a portion of the county’s sewage had to be diverted through the city of Dover’s sewer infrastructure to avoid continuous spilling.

“It’s been diverted already since at least the fall of 2014,” said Ms. Golt. “We found that there was some damage to the top of the pipe and at the time there was a release of wastewater at U.S. 13. A temporary repair was put in place, but the long-term fix will be slip-lining the entire thing to restore it’s integrity.”

The project laid out to address the issue calls for slip-lining the entire — roughly 3 mile length — of force mail from the area of Delaware Technical Community College’s Terry Campus south to Garden Lane by the Capital Commons shopping area.

Since the project is in such a high-traffic area, the planning stage has taken a long time. However, Ms. Golt estimates that work will begin shortly and will be complete in the next 12 to 18 months.

“We have the a preliminary engineer and our engineering report is complete, once we finish our design plan, the project can be bid out and then constructed,” she said. “It will be complicated because of maintenance of traffic, so a lot of the work will likely be done at night to be less invasive. With the way slip-lining works, we can dig pits every so many feet and slip and fuse the pieces of pipe together in either direction, so a lot of work can be done from inside the median. There will be different spots thought that will probably have lane closures because of the proximity of equipment. We need to protect motorists and the workers on the site.”

It’s thought that once the project is complete, the unpleasant odor coming from the pump station just north of the Dover Home Depot’s parking lot on Rt. 13 and Leipsic Road will go away.

Earlier this year Dover public works director Sharon Duca and Mr. Jakubowitch noted that the odor was likely a result of the increased wastewater flow that was diverted through the city’s pump station to prepare for the replacement of Rt. 13 force main.

Pump stations, also called lift stations, move wastewater to higher elevations to allow transport by gravity flow. Wastewater is fed into and stored in a sealed underground pit known as a wet well.

Once the Rt. 13 force main is repaired, wastewater can once again flow down it. Public works believes this will reduce the combined Dover and County wastewater flow currently being transmitted through that pump station thereby reducing the odor.

Ms. Golt also notes that the county and city are still working on short term measures to address the odor in the interim.

“We’ll be meeting again with the city in the next week or so to address this,” she said. “A vent fan was installed, but there is an additional carbon unit that we can use to help control the odor that we haven’t installed yet. We have to make a few valve adjustments so we can make that installation.”

Wastewater treatment plant plans

In early July, the wastewater treatment plant started discharging “undertreated” wastewater due to operational issues. In an ordinary day, the plant expels about 10 million gallons of fully treated wastewater subject to several different standards concerning nutrient, bacteria and suspended solid limits.

One bacteria they screen for, enterococcus, was significantly elevated. The plant’s permit limit for enterococcus colonies is 33 per 100 mL, but that number rocketed up to hundreds at some times to thousands per mL for several weeks. Once again, DNREC had to put a shellfish harvest restriction in place and recommended not swimming in nearby streams.

The issue began with a mechanical malfunction in one of the county’s wastewater plant’s 10 million gallon aeration basins — large holding or treatment ponds which promote the biological oxidation of wastewater.

The plant has two of these basins, but the north basin was in the process of being repaired when the south basin’s lining developed a hole. According to the public works department, it’s not uncommon for liners to fail, but to have it happen while the other basin was being repaired — thus unable to pick up the slack — caused the issue to snowball.

Repair work was finished on the north basin and it was brought back on line and treatment levels returned to the plant’s standard shortly thereafter. The shellfish harvest restrictions were lifted since then as well. However, the liner replacement process on the south basin is a process that’s taken months. The recent approval of spending on the new liner moved that project to the next stage in mid-November when Kent County Levy Court approved a bid for the basin liner and repair for $397,828.

Ms. Golt says the plant can meet it’s DNREC permit with only the north basin operational as the south remains down for liner replacement, but public work’s ideal is to have both up and running. This project is expected to be complete in the coming months as well.

After that’s complete, Ms. Golt says they’ll begin budget for a full liner replacement of the north basin as well.

“They were both aging, so it’s time to start budgeting for the north one as well so we don’t run into another situation like we had in July,” she said.

Levy Court commissioners also just approved a new position at the plant that Ms. Golt requested in November. A wastewater operations engineer — a position that would pay a salary starting at $73,908 — would help accommodate an increasing workload at the plant noted county personnel director Allan Kujala.

Ms. Golt said the county would select an applicant with a technical expertise in wastewater processing.

“This is not just a short term position, we’re looking at ongoing work in pipeline condition assessment, maintenance procedures and asset management work that needs to be done,” she said. “We have aging infrastructure and we need make sure that we’re addressing that in our pipelines and at the facility.”

Several other projects to update the plant and country infrastructure are also in various stages of completion, noted Ms. Golt.

“We connecting several communities to county sewer that have failing septic systems, we have a project to replace the plant’s blower, generator and some other outdated infrastructure — even though much of the plant has been updated, several crucial pieces of equipment also date back to the 1970s,” she said. “At the same time, we’re updating some pump stations, moving pipes to accommodate DelDOT work on the overpasses around Little Heaven and looking into “bio-solid dryers” at the plant.”

The public works department always has to keep one eye on the future as it works to maintain the existing sewer system, Ms. Golt noted. To this end, she said staff is always trying to find new ways to stay at peak efficiency to control electrical costs. The plant is already home to a large photovoltaic array to produce a significant portion of its own power. They’ve recently entertained the idea of installing an industrial digester that would enable the plant to produce power from the wastewater at the plant. Ms. Golt said they don’t have any plans to move forward with it currently though.

“We did an energy efficiency study with Honeywell and it appeared to be extremely costly,” she said. “The price tag for that project would be $34 million and would likely take over 20 years to pay for itself. There was an uncertainty factor about that payback too. In terms of whatever projects we move forward with, they have to be feasible, provide an overall benefit and be affordable.”

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