Wastewater Utility Accommodates Community Growth

Small Texas community’s collections system expansion stays ahead of rapidly rising population.

Wastewater Utility Accommodates Community Growth

Wastewater technician Bryce Skotnicki (left) and crew lead Leston Dhane log the condition and cleanliness of a sewer main prior to cleaning. This is the department’s policy every time a manhole cover is opened.

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To say that Princeton, Texas, is growing is something of an understatement.

The city’s population is on track to top 16,500 people by 2020 — 2 1/2 times the 2010 census count of 6,800. And the trend shows no sign of ending soon.

Princeton’s population explosion has been putting pressure on the community’s infrastructure and its utilities. Nowhere is that more evident than in the city’s Sewer Division.

And the city has stepped up to the challenge, says Tommy Mapp, Public Works director. Princeton is undertaking a long-term plan to replace old lines while it also installs new lines to meet the continued expansion. It has shifted from reactive maintenance to a new preventive maintenance schedule. And it’s preparing to implement a new asset management program next year.

Instituting CMOM

Princeton is located in north-central Texas about 33 miles northeast of Dallas. The community’s growth has been driven largely by an influx of new residents, many of them commuters working in Dallas and other nearby communities. In addition, commercial growth to serve the burgeoning market has added to the expanded population, Mapp says.

Princeton doesn’t treat its own wastewater but instead conveys it via a lift station to the North Texas Municipal Water District, which supplies water and also provides wastewater treatment to several cities in the region. The lift station currently has a capacity of 4 mgd but is undergoing an expansion that will initially double its capacity, with room to grow in the future.

Several years ago, the U.S. Environmental Protection Agency inspected the municipal water district, then followed up with inspections of the individual member municipalities’ operations. One result was an administrative order requiring several cities, including Princeton, to establish capacity, management, operation and maintenance programs.

Scheduled maintenance

Princeton’s city management and Public Works engineers responded with a plan for inspecting the system.

“That also changed the way we focused our efforts in preventive maintenance,” Mapp says. Princeton officials carved the city into four quadrants and divided in two the quadrant with the heaviest concentration of lines and other infrastructure — creating a total of five sectors. Then it put the inspection and cleaning on a five-year cycle, working through one sector — 20% of the system — per year.

“If we have a problem area, we can put it on a monthly or weekly cleaning schedule, depending on what the issue is, until we get the pipe replaced.”

The department also instituted a five-year capital improvement project plan. “Every year we reevaluate and reassess which portions of that CIP project are the highest priority,” Mapp says. “Things can change from year to year so that something we were going to do in year five is all of a sudden something we’re going to have to do in year one.”

When more immediate problems arise, the city’s response “really depends on the severity of the issue,” he adds. Some can be prioritized into the regular five-year plan, he explains. “But if an emergency comes up — a collapsed sewer main or something like that — we have funds set aside for emergency repairs.”

Except for regular flow studies on the system, which are conducted by an outside contractor, the inspection and maintenance program is largely handled in-house. Princeton has acquired two cameras: a push camera from PipeHunter and a Prowler tractor camera from UEMSI/HTV. The sewer division’s three crew members conduct the camera inspections between their normal service assignments.

Focusing on inflow and infiltration

The oldest portion of the wastewater collections system dates back to the early 1940s and was built with clay tile pipe. Where the system is growing to accommodate new construction, PVC is being used.

So far, the city has not tried any trenchless repairs, although it is studying the possibility. But because the old lines are mainly getting upsized when they’re replaced, neither pipe bursting nor lining would be satisfactory, Mapp says. “It’s usually cheaper to just go ahead and replace them with the larger pipe to accommodate future growth that we’re going to have anyway than it is to have to replace it twice.”

In the process of rethinking its approach to inspection and maintenance, Princeton also became more systematic in its approach to I&I.

The city has two kinds of I&I problems, Mapp says.

Some of them are in the clay tile pipe serving older residential portions of the city, including some mobile home parks. About 25% of the clay tile has been replaced with larger PVC pipe so far; the city’s long-range plans call for replacing all of the clay eventually.

But the other I&I problem has been cropping up in new construction.

As new residential areas are developed, water and wastewater utilities go in first, he explains. Subsequently, electrical, telephone and natural gas service are put in, and that’s where the trouble has occurred.

Installers of the other services had been breaking off sewer clean-outs by accident while doing their work, Mapp says. “Those clean-outs became a source of I&I.”

To resolve the broken clean-out problem, “We really have to stay on top of the developers,” he adds. “As soon as we notice one is broken or damaged, we repair it.”

Beyond that, the city has implemented a new procedure for additional — and immediate — inspections: first after the city sewer and water utilities are installed and then after the other services are installed. “That way we can hold accountable those who have caused the damages.”

Keeping pace

Princeton recently contracted to implement the Incode asset management platform from Tyler Technologies, with the enterprise system expected to go online sometime next year, Mapp says. The platform includes integration with the city’s GIS maps.

“That’s really going to help us utilize the employees’ time more efficiently out in the field,” he points out. Among other things, the system will allow the utility to assign new service orders to employees when they’re still out in the field on an earlier job, enabling them to go straight to the next order rather than driving back to the office and then driving back out again.

Another feature will allow city residents to report Public Works problems of any kind — not just the wastewater collections system — using their smartphone.

“The software also includes a preventive maintenance schedule, so like for our lift station, we can say every three months to go out and replace the oil in the pumps and it will automatically generate a service order to the department.”

Future growth remains “kind of tricky to calculate,” Mapp says. A 20-year outlook forecasts 13.6% annual growth for Princeton, “and last year we grew 30%,” he observes.

But for now, the sewer division has managed to keep pace with the growth, and Mapp doesn’t seem worried that it will get too far ahead of the operation.

Along the way, the entire department has worked to improve its reputation in customer service.

Princeton did that “through coaching on our side and really encouraging our employees,” Mapp says. Special training classes have helped department employees understand the importance of good customer service.

“It’s a slow process,” Mapp says. “But it’s working.”

Getting through the FOG

Like many municipal sewer utilities, the city of Princeton, Texas, continues to struggle with FOG — fats, oils and grease.

And as in many locations, the culprit is in part the local restaurant industry, where grease traps left unattended can result in the buildup of FOG in sewer pipes.

But Princeton doesn’t just target restaurants. The city is also working to enlist homeowners to help combat their own contribution to the FOG mess.

The Princeton Public Works Department includes an environmental education coordinator whose job is to help the public understand not just that problem, but others such as inflow and infiltration as well, says Tommy Mapp, the department’s director.

The city employs a variety of channels, including bill stuffers, classes and social media to get the word out. A mock-up of a grease-clogged pipe to show the public exactly what FOG does is another tool, Mapp says.

Classes on FOG convey the message: Don’t let FOG go down the drain. Wipe out pans with paper towels, and filter cooking oil to reuse it if you can.

The Public Works Department — which is also responsible for solid waste collection working with a private contractor — has established a drop-off point at its offices where consumers can leave their accumulated grease. Residents can also call for pickup, Mapp says.

So far, the classes have mostly drawn residents, rather than restaurant owners and other operators of businesses that tend to generate FOG problems.

“So we’re going to try to alter the way we communicate with those businesses,” Mapp says — perhaps with on-site training at restaurants to persuade the operators to take a more proactive approach to the problem and maintain their grease traps regularly, “and not just when they have to.”


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