Like many midsized cities, Haines City, Fla. (population 14,000), must struggle to get the most possible out of a limited budget.
Meanwhile, the city is growing rapidly, with numerous subdivisions planned, and has to be ready for increasing demand on its water and wastewater systems. On the wastewater side, the city meets those challenges by:
• Taking maximum advantage of gravity flow
• Planning ahead with the help of a Capacity, Management, Operation and Maintenance (CMOM) program
• Working collaboratively with consultants
• Implementing new technology slowly and with an eye on budget.
“Economics are a big driver, but we also have to plan for the infinite future,” explains Tim Tippery, superintendent of water distribution and wastewater collection.
Laws of gravity
“When you think of Florida, you think of it as being flat,” says interim public works director Mike Stripling. “But we’re on a ridge and have some issues. We’re probably pumping in some areas where we could use gravity.”
In fact, the collection system is roughly split between 100 miles of force main wastewater collection and 130 miles of gravity collection. The city owns 40 lift stations, mostly duplex and some triplex, for a total of 83 pumps, and maintains another 30 private pumps. In addition to maintenance, the wastewater department pulls some pumps and refurbishes piping. The staff calls in contractors as needed for bigger jobs. All in all, pumping is a significant expense.
To public works employees, it seemed that gravity could be doing more of the work. To investigate this, Haines City is working with a consultant, providing maps of areas where staff intuitively feel that pumping can be reduced.
“There are also areas where we think we can make significant improvement with a relatively short force main, and we have some lift stations that dump directly into manholes, which causes degassing and odor issues,” Stripling says. “We’re kind of a spread-out system, so the more we can do to shorten the trip, the better off we are. We’re always asking how to make the system more efficient.”
On the other hand, there are a few ways that gravity systems cost more. “In a gravity system, you can’t have any curves, and that rules out some methods of pipe installation and replacement,” explains Tippery. For example, Tippery would prefer to use horizontal boring methods to replace or augment lines at road crossings, especially since some of these lines are buried quite deep.
He has used jack-and-bore at times, but more often falls back on open-trench methods, which he regards as “still the standard for gravity systems.” Balancing the pros and cons of gravity systems is one of the more delicate decision-making processes for the utility.
A budget tool
“Our CMOM is basically a budgeting tool at this time,” says Tippery. “For example, if we’re TVing and we see a crack, we may not repair at that time, but we will add the cost of future repair to the budget.”
Before starting to think in terms of a CMOM program, Tippery says, the Haines City Wastewater Depart-ment had been mainly reactive. Now, staff members are trying for a more organized, proactive and coherent approach to maintenance and management, and they are looking farther ahead when it comes to capacity.
“We’ve been talking about this for years, and we’re starting to assemble pieces of the system,” says Tippery. In 1995, the city purchased a refurbished inspection vehicle from CUES Inc. The 1993 GMC van is outfitted with a pan-and-tilt color camera on a Pipe Ranger wheeled transporter. The CCTV unit has allowed the city staff to document system issues.
But Haines City is also finding ways to work with pieces of the system before they are a system in the truest sense. The CCTV unit, for instance, is not being used full-time. Rather, the repair crew gets it out when time permits between other jobs. Tippery estimates that televising the whole system would take five years in ideal conditions, and a part-time crew is obviously not ideal. To maximize the time that is spent on CCTV, crews work first on known trouble areas, and parts of the system that are still in clay pipe.
Making predictions
To address capacity, the department is working with consultants to project demand based on models, and on predictions of future developments. “The capacity part of CMOM is accounting for new buildings and new subdivisions,” says Tippery. “We’re trying to estimate our ability to handle new demand. Right now we’re working with consultants and spending about $75,000 to develop a model.”
To get the most from consultant time, Haines City does much of the data gathering. The public works department has its own GPS equipment and has located most of the features in areas of concern. Consultants then added detail as needed — for example, gathering inverts.
The city staff has also gathered flow data, but Tippery applies a rule of thumb to flow that means more to him than specific flow rates. “For gravity wastewater collection, I like to see a pipe that’s half full at capacity,” he says. “We collect flow data, but we also look at how full the pipe gets, which to me is more meaningful. Once we have that information, we look at what is more economical: parallel lines or replacement, rerouting, or adding lift stations and moving flow to a new gravity line.”
Based on the consultant’s work, Haines City is already starting to make decisions about new lines and upsized lines. One complication is the nature of Florida Department of Transportation (FDOT) rights-of-way.
“FDOT rights-of-way are very crowded, so sometimes we have to find a back door of some kind because there’s just no free space, even for an upsize,” explains Tippery. But that is something of an advantage, because Tippery has a distinct preference for multiple and parallel lines, rather than big single lines.
“I hate having all my eggs in one basket,” he says. “I prefer multiple routes over one big line, because I like options. When you have one big line, and it fails, then it’s a big deal. I often choose parallel lines to avoid this.”
Dealing with the old
As is often the case, new lines to serve new development aren’t the problem. In the Haines City region, orange groves keep turning into houses. New lines are sized to accommodate up to 20 years projected expansion and are relatively cheap and easy to install.
But upgrading old lines is another story. For one thing, they’re often in backyards. “During the 1950s, it was common practice to run utilities in backyards,” Tippery says. “That’s where we get most of our root problems now, and it makes it harder to maintain and improve lines.” The city uses a Vactor 2110-44 combination truck to clear the laterals, then adds RootX chemical root treatment. Specific areas, usually backyards with gravity systems, are treated once per year. All other RootX applications are random.
The CMOM program is also helping Haines City to deal with grease, a recurring issue. “Our oil and grease program is really reducing issues,” Stripling says. “We’re getting the word out to businesses in town. We’ve established collection points for residents to dispose of grease, and we’re getting information out to commercial areas, making sure that they’re doing their due diligence and cleaning traps and such. That program is going well.”
A key feature of the grease and oil program is getting mobile home parks involved. “We’ve collected hundreds of pounds from parks,” Stripling says.
Dealing with a variety of issues proactively is the essence of CMOM. Haines City is demonstrating a little CMOM is a good thing, and that thinking with a future orientation is a good idea, even on a small scale. The program offers returns even at beginning stages.
