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Grinder pumps offer cost-effective solution for Virginia town
Mary Ball Washington, the mother of the U.S.’s first president, was born in the parish of St. Mary’s in Lancaster County at the southern tip of Virginia’s Northern Neck Peninsula. Although her son’s portrait resides on the $1 bill, Lancaster County—like counties and municipalities throughout the United States—has lacked funding earmarked for capital improvements. As a result, their utility infrastructures are small in scope and widely spread.
The town of Kilmarnock, the county’s largest (population: about 1,200), is the only area that provides water and sewer service to its residents, according to the Lancaster County Profile, while the smaller towns of Irvington and White Stone provide only water service. “Elsewhere, on-site septic systems and wells treat wastewater and supply water,” the Profile says.
For some low- to moderate-income residents in Lancaster County’s Greentown, even those rudimentary onsite systems have been scarce—and what was present was lacking.
The county made its first attempt to remedy fragments of its infrastructure problems in 1998 with the establishment of an Indoor Plumbing/Rehabilitation Program. Around 2005, the county’s housing director began seeking outside funding to introduce a modern infrastructure to about 50 homes dispersed over 160 acres in unincorporated Greentown, many residents of which are seasonal workers or employed at the Tides Inn, a nearby luxury resort. Also in close proximity are high-value homes built by empty nesters lured to the still-affordable waterfront property Lancaster County offers along the Rappahannock River and Chesapeake Bay.
But even fiscal com-plications for the project in Greentown initially had to take a back seat until the county could resolve other essential issues.
“There was no county or resident experience with public sewer utilities,” said W. Ben Burton, P.E., of Bay Design Group in Glenns, Va. “No available treatment facility. A general lack of local funding. A need for the easiest long-term operations and very low maintenance requirements,” he added.
“The greatest obstacle was where to put a wastewater treatment plant and what type of plant could be used,” said former county administrator Bill Pennell, who retired in 2011. “Lancaster County believed that some sort of pump system would have to be used if the processing plant was located in Kilmarnock, at the Tides Inn or elsewhere. Lancaster County tried to attach to the Kilmarnock wastewater treatment infrastructure, but town officials would not approve this strategy,” Pennell said.
“When we learned of the possibility of putting a wastewater treatment plant on an abandoned piece of land in the neighborhood, the county condemned the property—it was in an estate and the original owner had been deceased for 50-plus years—and paid the heirs their portion of the appraised value of the land,” Pennell added. (The wastewater treatment plant was funded separately from the ensuing sewer project.)
Furthermore, “there was an anti-growth citizen organization that created numerous roadblocks to the county’s original plan, but a later modification to the county’s comprehensive plan overcame that obstacle,” Pennell said.
The area’s landscape proved another formidable challenge for engineers and the job’s budget. Original designs called for a hybrid system, primarily gravity with some minor perimeter low-pressure sewer installations to handle extremes. Although soil conditions are rich for Lancaster’s notable agricultural sector, they and Greentown’s high water table also are not conducive to the installation of gravity sewers.
“Vacuum was also considered, but it is more maintenance- and operations-intensive than the county could absorb,” Burton said.
Then came the sticker shock for the gravity-LPS hybrid: “A single 2014 bid was received at $3.5 million, which significantly exceeded available funding,” Burton said. The price tag represented more than 10% of the county’s FY2015 total revenue of $28.5 million and exceeded the U.S. Department of Agriculture (USDA) grant and loan for which it had applied.
Burton, as project engineer, said Greentown was “redesigned as a total low-pressure sewer system with an acceptable $1.1 million sewer system budget, exclusive of design, administrative and legal fees. Multiple bids were received and the final project [$847,980 for construction] was awarded to Franklin Mechanical Contractors Inc. of Kilmarnock in late summer 2015.”
Frank A. Pleva, the current county administrator, told Lancaster County’s Board of Supervisors at the time that the final construction amount “is 25% less than the project’s construction cost estimate in the engineer report.”
While the original hybrid system only called for nine grinder pump stations, the revamp would total more than four dozen. The inclusion of grinder pumps manufactured by Environment One Corp. (E/One) of Niskayuna, N.Y., was a decisive factor in the design because of their “performance and long-term reliability,” Burton said.
The grinder pump is the heart of the All-Terrain Sewer low pressure system from E/One used daily by more than one million end-users worldwide. The ATS begins with a tank about the size of a dishwasher that is buried in the ground. Interior components include a 1-hp, semi-positive pump that grinds waste into fine slurry. Its robust torque can propel the liquid through the inflow- and infiltration-free pressurized 2- to 4-in. pipe for a distance of two or more miles—even uphill—to a force main or treatment plant.
Fifty E/One grinder pumps were installed in Green-town “with the ability to add more,” Burton said. “They connect to 2-in., 3-in. and 4-in. low-pressure mains on public and private roads and discharge to the new wastewater treatment plant.”
Greentown’s system is county-owned and will be maintained by a third party wastewater treatment plant and system operator, Burton said. If service is required, the pump can be extracted and replaced quickly, meaning minimal maintenance costs and inconvenience for the homeowner. E/One’s average residential user can expect a span of eight to 10 years before the first service call.
The county’s direct funding proportion of the project—part of a multi-year capital improvement plan—was slightly offset by a $4,500 connection fee, which was waived for low- and moderate-income residents, Burton said. Each homeowner pays a $35 to $38 monthly home fee and supplies the electrical service for the energy-efficient (less than 10 kWh per month) grinder pumps.
Most of the project, however, was financed by a USDA rural development grant and loan. The county received $511,000 in grant money from the USDA and issued a revenue bond of $170,000 to be sold to USDA with a two-percent interest rate over 40 years.
USDA loans—$299 million for 88 projects was announced in November 2015 as part of its Water and Waste Disposal Loan and Grant Program—are vital to the communities eligible to receive them, but nearly impossible to obtain without experienced personnel to navigate the application process.
An Affordable Option
Even with USDA assistance, the project’s budget would have been woefully short if gravity had remained the only option. Without the sewer, Burton said, price would have “postponed the project indefinitely.”
“Greentown would not have had access to a public sewer system,” said Les Thorpe, a sales engineer for Commonwealth Engineering & Sales, the local E/One distributor. “The funding was not in place to provide gravity sewer service to everyone, and this community would have been faced with continuing to use straight pipe discharge or failing septic tanks. Because of the All-Terrain Sewer, the engineer was able to design a reliable sewer system, giving the residents a connection to a public sewer system and put to use their brand new wastewater treatment plant which also will help to keep their properties and the local waterways clean.”
“All of this provided every resident with a connection to a public sewer and came in under budget by utilizing ATS technology. And the community was saved over $2 million,” added Joe Clark, a regional manager for E/One.