Water Woes Continue to Baffle

By Kim Siebert MacPhail

Bedford’s Pine Hill water tank is expected to be back on line in late August.

After continuous, around the clock monitoring, daily meetings and multiple phone calls with the state’s Department of Environmental Protection, hands-on assistance from the MWRA’s Mobile Disinfection Unit, an extra 36 million gallons of water to flush the system, and depleted overtime accounts for Water and Sewer departments, DPW Director Rich Warrington remains baffled by the persistence of total coliform bacteria in Bedford’s water system.

Warrington stresses that “total coliform bacteria are not harmful.” Instead, the presence of total coliform indicates that conditions are ripe for more dangerous types of bacteria—such as E. coli—to develop.

“Every time we test for total coliform, we also test for E. coli,” said Warrington at the August 20th Selectmen’s meeting. “We’ve never found any.”

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“It’s frustrating,” he said of the ongoing presence of total coliform bacteria.“I’m confident our approach to the problem is sound but nevertheless, the system has been slow to respond to our efforts…. The idea is to get as much chlorine out there, get it out as fast as possible, reduce the age of the water in the system and that should do the trick….We’re continuing to deploy as many different weapons as we have…. We’ve cleared all the sites that were positive but we will be taking another set of town-wide samples on Thursday (August 23rd) and we’ll be anxious to see if they’re all clear.”

To illustrate the course of action taken in response to the positive total coliform tests, Warrington distributed a nine-part, detailed action plan, originally written to the state’s Department of Environmental Protection on August 16th.

According to the memo, the Town has responded to the problem in these ways:

  • Installation of temporary disinfection systems at the four public schools.  Because the water lines to the schools have been largely dormant all summer, the DPW has flushed them and set up disinfection stations. Hypochlorite is being injected into the systems and each system is inspected daily. Testing from the end of last week showed no total coliform, but, as mentioned above, testing will continue this week. It is not Warrington’s intention to maintain the school located disinfection stations after classes begin. We’re preparing all the permits needed to do that but don’t want to go forward unless we have to,” Warrington explained. “Since there’s no health impact now, why introduce something like that? We want to make sure we don’t do harm. It is an option but we’d rather use bottled water ifit came to that…. It would be at four schools, it would have to be monitored all the time, and to build it in a fail safe manner….there’s not a lot of comfort level there.”
  • Continuation of ongoing flushing to reduce water age in the distribution system. In an attempt to draw adequately chloraminated water at a quicker rate through the system, hydrants have been opened to aid in water circulation. This has affected water pressure at the far edges of the town,on streets like Fox Run near the Billerica line. Water age in the pipes is suspected to be a contributing factor in the ongoing total coliform readings. Warrington noted at the Selectmen’s meeting that most of the hydrants have been sealed once more.
  • Supervisory Control And Data Acquisition (SCADA) programming modifications and operational modifications. “Basically,” said Mark Johnson of the MWRA, who was also present at the Selectmen’s meeting, “SCADA is an instrumentation system that allows the control valves to bring the water from Lexington into Bedford and integrates their operation with the water storage tanks.” It is thought that fluctuations in water levels, inside the Pine Hill water tank in particular, may create less favorable conditions for bacteria development.
  • Cleaning and lining the Fletcher Road main. The cast iron pipeline from Great Road to the Pine Hill tank is one of Bedford’s oldest and part of the original water system.
  • Reactivation of the Crosby Drive standpipe (water tank). The tank has been emptied and scrubbed and put it back into service. The water mains leading to Crosby Drive are newer and cement-lined, unlike the cast iron pipes from the original water system. The capacity of the Crosby Drive tank is 1 million gallons and is mainly intended for use infighting fires.
  • Reactivation of the Pine Hill standpipe (water tank).This tank is where the problem of total coliform was first detected. The capacity of the tank is 1 million gallons and, like the tank on Crosby Drive, the water is mainly intended to increase the ability to fight fires. It serves all of West Bedford in this function. Warrington expects Pine Hill to come back on line in late August.
  • Aggressive flushing of selected pipes (mainly through hydrants).When the water enters Bedford at the Lexington line, chlorine in adequate amounts is detected. That chlorine is rapidly lost so that by the time it gets to the center of town, it has all but disappeared.The same problem is also noted at what Warrington called “the fringes of thesystem.”Warrington said that the DPW had run “double water through the system for a couple of weeks,” notingthat this is the standard protocol in the situation.
  • Use of Burlington interconnection to obtain water. “Burlington has supplied us with upwards of 400-500 gallons per minute over in the Network Drive area and that has been very helpful. That’s been very good for our system right now because it is chloraminated water also. But they took a lightning strike a week and a half ago and blew half of their lines out on the wells,” Warrington said.“We have talked to Billerica, too, but we’d need to do some structural work before that connection is possible.”
  • Reactivation of Shawsheen Road wellfield.Work to replace this well is due to be completed in the near future. The DPW does not plan to activate the well until after the reactivation of the Pine Hill tank and the end of the flushing program. The Shawsheen well water is not treated with the same additives as MWRA water and, for the duration of the testing period, it is preferred that only chloraminated water enter the system.

During Warrington’s presentation, Selectman Bill Moonan asked if the summer’s high temperatures had played a role.

“We do suspect it would go away on its own if we did nothing—probably by December the system would adjust itself. We know that temperature is one of the elements that’s causing this to happen. Biofilms can develop and harbor bacteria,”Warrington responded.

Selectman Margot Fleischman added, “We are one of the three towns in the [MWRA] system to experience this problem and the only one that was actionable. It struck me that a lot of other towns must have similar infrastructure to ours and I wonder what might be different about Bedford? Or is there something different about Bedford’s infrastructure? Is our infrastructure older than our neighboring towns? Because obviously it’s hot everywhere. Why are we the only one of all these communities that’s having a problem?”

“That’s probably the million dollar question,” replied Warrington. “There are other towns, very similar, at the fringe of the system. The water is coming in very warm—72 degrees…. When you think about it, that water originates at Quabbin Reservoir, enters into Wachusett Reservoir after going through a very deep tunnel and enters another very deep aqueduct with a ground temperature of high 40’s/low 50’s. The only time it gets exposed is when it hits the MWRA Walnut Hill tank in Waltham or the Turkey Hill tank in Arlington. Then it gets back in the pipes and comes to Bedford. Somehow it gets up to 72 degrees.”

MWRA’s Mark Johnson added, “Temperature is playing a very big role and we’re seeing it in all our tanks across the system. The heat wave this summer has been really extraordinary. It’s been the hottest July on record. The other common denominators are the unlined cast iron pipe and the lack of circulation in some of the pipes. It becomes an ideal condition for potential bacteria growth.”

Chairman Cathy Cordes asked Warrington to give the Selectmen an early estimate of how much it has cost, so far, to address the problem.

“In terms of water, we’ve put approximately 36 million extra gallons of water through the system at just under $3,000/million gallons. We’ve also taken about 18 million gallons from Burlington and they generally charge us about what Lexington charges.  So we’ve got about $45,000 worth of water there. The overall budget for water…we’ve been running a surplus. Last year, we turned back about $60–$70,000. Taking that into account and depending on how kind the rest of the year is to us, we could possibly come in within the budget, assuming no more heavy, constant flushing.”

As for department overtime expenses, the water division’s budget has been depleted for the year. Warrington hopes that with some creative scheduling and use of cross-trained staff from other departments, things might work out. “But if another Halloween storm or another Hurricane Irene happens, all bets are off,” he cautioned. “I hope to absorb it, but I just can’t guarantee [that].”

Warrington also itemized other long-term actions that might be taken to address the potential for recurring problems. They include:

  • Lining the approximately 36% of piping that is not currently lined. After the Fletcher Road and Great Road pipe lining projects are completed, about 34% of Bedford’s pipes will still be unlined. Page Road is slated for lining next after the Great Roadproject is completed.
  • Installing mixing mechanisms in the water tanks to keep a water current moving so that bacteria has less of a chance of forming. Mixing apparatus could be solar-powered.The cost estimate is $40,000 per tank, and other towns, like Burlington and Lexington, have been installing them.

In the meantime, Warrington continues to work with what he called “three or four of the country’s best water minds” to solve the problem.

“It sounds like we’re doing everything we can think of,” said Selectman Moonan.

“We appreciate all the work that’s gone into this,” said Cordes. “It’s an unfortunate situation, but the water is still safe to drink.”

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Alethea Yates
August 22, 2012 6:34 pm

An excellent article! Most informative.

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