Persistence Pays

An aggressive and steadily expanding preventive maintenance program in the North Carolina capital reduces SSOs to keep sewer lines in optimal condition

Determined to reduce sanitary sewer overflows (SSOs) and make its collection system perform at optimal levels, the City of Raleigh Public Utilities Department has built a comprehensive cleaning, root control and inspection program that achieves solid results on a consistent basis.

The preventive maintenance program didn’t just happen. Over the last 10 years, the utilities department in North Carolina’s capital has steadily and consistently added equipment and personnel, building a fleet and team considered large for the city’s size.

­Raleigh’s aggressive plan incorporates three key components:

• Regular and concentrated cleaning, which has reduced emergency calls and improved system function.

• CCTV inspection, which helps monitor system health and measures the effectiveness of the cleaning crews.

• Community outreach through “billboards.”

All these have helped the city bring the system’s number of SSO incidents down to fewer than one-third the national average of systems of comparable size.

Making the case

To develop the program and build the required fleet and team, sewer collections superintendent Hunter Stanley knew he had to convince the city council and department management. “There’s an old saying that I put to our city and the agency management,” he says. “‘You can pay me now or you can pay me later.’

“We can either budget now to get the equipment we need to stay ahead, or later on the federal government could come in here and tell us we’re going to get the equipment and put us on a mandatory program. If we don’t have the tools and means to clean the lines, we are going to have a lot of SSOs, and that’s not where we want to be.”

Heeding Stanley’s advice, the council and his superiors agreed that over time, Stanley would procure equipment and hire personnel to build an aggressive and proactive preventive maintenance program for the region’s 2,300-mile collection system.

Beginning in 1997 and every year until 2008, Stanley acquired new combination sewer cleaning vehicles, mechanical rodders, small flush trucks, bucket machines and CCTV inspection vehicles. The fleet now includes 16 flush trucks from Vacall Industries Inc. The largest ones carry 1,500-gallon tanks and pumps that deliver up to 80 gpm, and the smaller units have 900-gallon tanks and 60-gpm pumps.

Other equipment includes a 4x4 combination unit from Vactor Manufacturing (40 gpm), four mainline CCTV rigs from Aries Industries Inc., mechanical rodders and bucket machines from Sewer Equipment Company of America, and an easement machine that Stanley and his team designed and built from various components.

Using the tools

In this day of technology and computerized systems, the utilities crew still relies on what Stanley affectionately calls “an ol’ country boy work system.” Scheduling and management is handled through an organized, manual map method. Stanley uses a map book, extracting each page, which in turn is copied and becomes an assigned work zone for a specific crew. The crew is charged with cleaning every line in the area on the map. When they finish, they return the map to Stanley, who has a duplicate copy on the office wall, which then is marked as complete.

The crew’s completed map page is then filed in a book that indicates the crew members’ names, the date the area was assigned and the date it was completed. “Many cities I speak to are sending their crews out to ‘fight fires’ and are working in different areas instead of concentrating efforts,” Stanley says.

“We have found that by keeping our PM crews focused on one area until it is complete, we are able to stay ahead. When you jump around, it is almost impossible to ever catch up on the work that needs to be done.” Between its in-house crews and an outside contractor, Raleigh consistently cleans 300,000 or more feet of sewer main per month.

­The city contracts its chemical root-removal program to Duke’s Root Control Inc., and contracts planned maintenance for its sewer mains to Hydrostructures in nearby Pittsboro. “Both do an outstanding job and are very professional and honest,” Stanley says.

The system includes primarily 6- to 12-inch mains made of VCP, concrete, ductile iron and PVC. Roots have been a challenge of late because of the severe drought conditions in the Southeast. A large share of the system is VCP, which is particularly susceptible to root intrusion. As a standard practice, when crews clean the lines, Stanley has them run a cutting saw through at least once after standard high-pressure waterjet cleaning is complete. This helps ensure that all roots and debris have been cleared.

For larger lines, the crews sometimes opt for bucket-machine cleaning. “Although a lot of cities don’t like to do this anymore, we still do,” Stanley says. “On large lines that may be filled with a buildup of sand and gravel, a flush truck could clean the line, but it takes a lot longer and sometimes it just can’t get everything.”

Tough to reach

To perform maintenance in hard-to-access areas, Stanley developed his own easement machine, using a John Deere tractor, a detachable hose reel with a three-point hitch, and 600 feet of hose. When it isn’t required for cleaning lines, the crews can easily disconnect the reel and use the tractor for other tasks, like easement clearing.

Grease is a persistent problem in some areas of Raleigh where the population and usage are dense. Here, an effective tool is Bison chemical grease removal and control agent. Always looking for better ways to maintain the system, Stanley and his crews developed a cost-saving method for dispersing the Bison agent in place of the traditional method of loading 10 gallons of concentrate per 1,000 gallons of water directly into the flush truck tank.

The crews created a special container with a controlled-release switch that is attached to each of the cleaning trucks. The chemical is now dispersed only when needed in lines with heavy grease buildup and where the treatment will help reduce the return of buildup once the cleaning is finished. This one small innovation on the cleaning trucks is greatly reducing treatment costs and unnecessary use of the chemical.

Quality control

In addition to its own preventive maintenance and emergency response duties, Raleigh’s CCTV inspection crews perform quality-control checks on cleaning crews and help monitor the overall health of the system. Periodically, the city creates a work order for one of the CCTV crews to perform a spot check on a line recently indicated as cleaned.

“With a workload as big as ours, we just can’t take a crew’s word for it,” Stanley says. “We TV behind the cleaning crews to make sure they are doing their job. If I send a truck out there and that line has not been cleaned, and they came in with their paperwork saying that it was, somebody’s going home for a couple of days. Once you get it across to your crews that you are going to check behind them, and that not doing their job will result in disciplinary action, they’ll be sure to perform to the best of their ability.”

Stanley is quick to give credit to assistant superintendents Tom Johnson and Phillip Maddox. “We’re all on the same page when it comes to preventing SSOs,” he says. “We also have excellent supervisors and crew members in this department. Supervisor Alexander Rogers has been here for 31 years and knows the system like the back of his hand. His father retired from here with 30 years of service.”

Crew performance is critical, but equally vital is equipment maintenance and reliability. To help the crews stay on target, a full-time garage with two mechanics is dedicated to the maintenance and repair of sewer-related equipment.

Consolidation of vendors also helps. For example, all Raleigh CCTV equipment is made by one vendor (Aries). By narrowing the makes and models of equipment or brands, Stanley can more easily keep sufficient spare parts on hand for repairs to be handled by in-house staff. That reduces downtime. Larry Murrin, supervisor II, is in charge of the TV crews, who repair cameras in-house and so save the city money.

Community on board

As the crews make their rounds section by section throughout the system, Stanley sees an opportunity to educate residents in a unique way.

Using large laminated wrap graphics, similar to those that display advertising on public transit vehicles, Raleigh has applied “billboard” messages to its cleaning trucks. They educate people about the proper disposal of grease and other ways they can help prevent SSOs and improve the health of the sewer system. When the trucks are deployed in a concentrated area in a neighborhood over several days, the hope is that most area residents will notice them and read the messages.

The city’s multipronged effort against SSOs seems to be working. A study by the National Association of Clean Water Agencies shows that an average of 140 SSOs occur annually per 1,000 miles in a metropolitan sewer system.

As a result of its commitment to preventive maintenance, Raleigh experienced just 48 SSOs in 2007 that reached the threshold that the state Division of Water Quality defines as requiring the city to notify the public by issuing a press release (21 of those were caused by grease in the lines). That places the city considerably better than the national average. The goal is to bring SSOs even lower as the program progresses.

“We couldn’t have done it without the support of our city and management and their permission to get the equipment and personnel we needed to do the job right,” says Stanley. “I have had the backing of my superiors since I have been the superintendent, and we have had the money we need to do our job. Also, everyone in Public Utilities works very well together.

“You cannot keep a large system like ours clean and performing well with a handful of trucks and people,” he says. “You’ve got to have the right number of units and personnel. That’s the secret to controlling SSOs and staying ahead of potential problems.”



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