Out With Waste

A Massachusetts water district earns accolades for energy and water conservation, while plant operators learn new technologies and skills.
Out With Waste
Todd Melanson at the Crooked Spring plant’s solar array, which supplies the facility with a majority of its electricity.

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An impressive solar panel array sits in the field behind the Crooked Spring Water Treatment Plant, one of three plants owned by the Chelmsford (Mass.) Water District. The solar panels, installed in 2010, save some $154,000 a year on electricity.

That’s just one example of energy and cost savings the district has achieved. Other measures include energy efficient lighting with timers that shut the lights off when a room is vacated, a hybrid vehicle and infrared heating to replace direct hot air heating in the district garage.

Water conservation is another initiative. “When I started at the district in 2007, we didn’t meet the water conservation rule restrictions,” says Todd Melanson, environmental compliance manager. “We now meet or exceed the 65 gallons per capita per day Water Management Act goal, set by the state. We were averaging 69 gpd, and now we’re averaging a steady 62.”

The district is working with the Town of Chelmsford to retrofit municipal buildings with water conservation devices. The district also purchased leak detection equipment.

Chelmsford Water was recognized for its water and energy conservation with awards in 2012 from the Massachusetts Department of Environmental Protection. The district also won the Massachusetts DEP Public Water System Award in 2010 and 2013, and the Drinking Water State Revolving Fund Award and a Governor’s Citation in 2010.

Plant operators do their part for conservation. “Any time you can save on energy, it’s a fabulous thing,” says Bill McCarthy Sr., senior water quality manager. “We track the solar array efficiency every day with the computer, and if there is a problem, it trips an alarm.” Melanson jokes, “We watch the environment more than the environmentalists.”

Serving the town

The Chelmsford Water District serves 85 percent of the town, providing water to more than 25,000 residents. The district maintains 19 wells, 140 miles of water mains and 1,498 fire hydrants. Eighty-two percent of connections are residential, 17 percent are commercial and industrial, and the rest are municipal.

Water withdrawn from the wells comes from both the Merrimack and Concord River basins, and above-ground water reservoirs hold one of the state’s largest capacities at 15.3 million gallons. Water from 19 gravel-packed wells is piped to the Crooked Spring, Riverneck and Smith Street plants, where it is treated and tested. Potassium permanganate and sodium hypochlorite are added during treatment, and potassium hydroxide is added after treatment as a corrosion inhibitor.

The district organization is divided into treatment, distribution and administration. Personnel in the departments are cross-trained and work cooperatively. The Crooked Spring and Riverneck plants run year-round, and the Smith Street plant runs during the peak season (May through October) and when one of the other plants is shut down for maintenance.

Four treatment operators staff the plants on a rotating basis, and the team also includes nine distribution and six management and administrative staff. The operators are all certified, as are most of the distribution and administrative staff.

Modern plants

“When I started with the district in 1973 at the Smith Street plant, the treatment process was diatomaceous earth,” says McCarthy. “We’ve come a long way since then.” Built in 1964, the 1 mgd Smith Street plant was upgraded to an Aria (Pall Corporation) membrane filtration system in 2012. “The membrane system is more efficient than the old diatomaceous earth process and was able to fit in the existing building, which was a key requirement because of the plant’s location,” explains Melanson. The 3 mgd Riverneck plant, built in 2000, and 4 mgd Crooked Spring plant (2007) use aeration and greensand filtration.

“Before the Riverneck and Crooked Spring plants went online, we had a problem with manganese and iron precipitating out and staining the fixtures,” says Melanson. “It was more of an aesthetic issue, but we installed the treatment plants to solve that problem.”

Besides starting the process of removing manganese and iron, the aeration towers at each plant remove odors and dissolved carbon dioxide and help adjust the pH before the actual filtration process. The aeration towers have reduced the plants’ use of potassium hydroxide chemical by 30 to 40 percent. “With the cost of drinking-water-quality potassium hydroxide increasing by as much as 200 percent a year, the savings have quickly added up,” says Melanson.

“The district operates in an environment with a high chance of volatile organic compound (VOC) contamination, so the aeration towers help protect the water by completely air stripping out any possible contamination, should it occur,” says Melanson.

All the district’s plants meet the 4-log reduction Groundwater Rule, which means the district can prove on a daily basis that it removes 99.99 percent of all potential bacterial contamination. “We increased the chlorine level before the rule went into effect, but with the intention of meeting the 4-log requirement,” says Melanson. “The increased chlorine dose also helps remove iron and manganese. The processes we have work great and produce excellent quality water.”

Going green

Soon after hiring Melanson, district leaders asked him to evaluate energy consumption and efficiency. He’s also in charge of emergency response, community outreach, training and making sure sampling and water restriction requirements are met.

“The district wanted to lower its energy costs, so I started looking at ways we could do that,” Melanson says. “Because our facilities were all pretty new, there wasn’t much we could do at that level, so we started looking at renewable energy sources.” In 2008, he attended an energy roundtable with state DEP, the U.S. EPA and the University of Massachusetts–Lowell, where he got advice on renewable energy options.

He settled on solar and connected with a solar engineering graduate student at UMass-Lowell, who performed a feasibility study. Using federal stimulus funds, the district built the $2.8 million solar array at the Crooked Spring plant.

Commissioned in fall 2010, the array was one of the largest ground-mounted systems in New England. It includes 2,310 solar panels, each with a capacity of 205 watts, or about 550,000 kWh per year. Besides the energy savings, the plant earns a renewable energy credit for every 1,000 kWh generated, for an annual savings of $30,000, in addition to the 54 percent reduction in electricity use. Operators have taught themselves how to use software that tracks the solar array’s efficiency.

Good communication

The operators also work efficiently to run the three plants, relying on good communication. The operators and distribution group work together. “They’re all one unit, and they have to plan out the schedule to make sure everything is covered,” says McCarthy. “The distribution staff lets us know when they’re going to test the hydrants, since that influences the plants’ flows.”

The state requires each plant to be staffed for four hours a day. SCADA system alarms let operators know of any problems during unstaffed periods. “Operators are cross-trained on all three plants and can step up to fill another’s shoes,” says Bob Hayes, chief plant operator.

McCarthy holds Level 3 water treatment and water distribution (3T/3D) certification, and has been with the district for 40 years. Hayes (17 years) holds 3T/2D certification. Plant operators are Steve Pynn (3T/2D, 12 years) and Bill McCarthy Jr. (2T/2D, 6 years). The operators handle maintenance, grounds work and plant upkeep, and order and track supplies, such as chemicals. Benchtop testing is done at each plant, and samples are sent to a state certified laboratory to meet state testing criteria.

Compliance with the 4-log rule means keeping meticulous records of plant flows, chlorine dose and chlorine contact time. “Starting the first of every year, we record the flows and chemicals, and the state goes through the books every three years to make sure we’re doing what we say we’re doing,” says McCarthy.

Self-sufficient

The Crooked Spring plant is designed to be self-sustaining in case of emergencies. “This started after 9/11, so that if the plant had to be secured and locked down, it could still operate,” says McCarthy. The plant has a full kitchen, generators and a fuel supply, and two radio frequencies for line of sight. “We did that so the lines wouldn’t cross,” McCarthy says. “It used to take two and a half minutes to get information from the SCADA, and now it takes six seconds.”

The district belongs to the state’s water and wastewater response network, which allows utilities to respond cooperatively to statewide emergencies with personnel or equipment.

Melanson conducts regular safety and emergency response training with the staff. The operators also attend water association tabletop exercises and seminars.

Operators rely on each other to solve problems. If for example they visit a well site and find something that needs fixing, or if they are having difficulty with chlorine levels, Hayes asks the team to look at the situation and come up with an answer.

“The operations team is the strongest and most conscientious I have seen in my career,” says Melanson. “They all grew up in this town, have worked in the district for a long time and have been through a lot together. If there is a problem at a plant, they are ready to handle it, even if it’s at two a.m.”

McCarthy adds, “I consider myself an equal to the operators. No one is above the other. Every day, they are meeting challenges, and every time they open that door they might be faced with a situation.”

Melanson adds, “The operators treat the entire water system as if it’s alive, because you can’t do something to one part without it affecting the others. The plant is the heart and the distribution system is the veins and arteries. The system operates continuously and if something happens to one portion, it can affect the entire community.”



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