Deb LaVergne grew up just a stone’s throw away from the Blackstone River in Massachusetts. And she’s spent her career helping to clean it up.
As laboratory and pretreatment manager for
the Upper Blackstone Water Pollution Abatement District, she makes sure the effluent from the district’s wastewater treatment facility meets strict discharge requirements. It’s a critical job because, as she says, “Where we’re located, our effluent makes up most of the river’s flow.” In other words, the performance of the plant has had everything to do with improving water quality in the river.
“When I was little, we’d go down to the river and it would be red or blue or green, depending on the dye the local textile mills were using,” LaVergne recalls. “It was dead. There wasn’t anything living in it at all.” Today, she says proudly, the river supports populations of fish, muskrat, and crayfish.
For her efforts, LaVergne was honored with the 2008 Laboratory Proficiency Award, given by the Massachusetts Water Pollution Control Association to someone who exemplifies “outstanding dedication and integrity in laboratory analysis, reporting and follow-through.”
Her nominator, colleague Sharon Lawson, says LaVergne really cares about the quality of the water in the river: “She’s a lifer for the environment.”
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The laboratory LaVergne manages has a full-time staff of four, plus up to three part-timers, and operates seven days a week. It’s big and busy because the Upper Blackstone Wastewater Treatment Facility is, too. The district it serves includes Auburn, the Cherry Valley Sewer District, Holden, Millbury, Rutland, West Boylston, and the city of Worcester. The district also serves portions of Oxford, Paxton, Shrewsbury, and Sutton and treats septage and sludge from numerous other communities.
The current treatment plant replaced an old trickling filter plant and went into operation in 1976. It is now an advanced treatment facility, providing phosphorous and nitrogen control, with an average flow of 45 mgd.
The district recently completed a $140 million improvement that modernized air pollution controls, constructed a new landfill, updated the laboratory, and improved stormwater management, wastewater treatment, odor control, and plant instrumentation. Later phases of the project will provide more efficient solids management and expand treatment plant capacity.
As it is, however, the plant has done an excellent job fulfilling its mission of improving the water quality in the river and protecting its headwaters from contamination. “We’re actually achieving a higher standard of performance than was envisioned when the plant was designed and constructed, but we must achieve even more stringent standards in the future,” says plant manager Paul Caron.
Flow first passes through screens and aerated grit chambers to remove debris and grit and freshen the wastewater. Wastewater then passes through a Parshall flume and into primary clarifiers. In the activated sludge basins, BOD, phosphorus and nitrogen are treated. Effluent is chlorinated, dechlorinated with sodium bisulfite, and discharged directly to the Blackstone.
Waste activated sludge thickens in dissolved air flotation thickeners, aided by polymer addition. A sludge holding tank blends thickened WAS, primary sludge, scum and imported solids. Komline-Sanderson belt filter presses produce a 20-25 percent solids cake that is burned in the plant’s multiple hearth furnaces. Excess heat from the combustion process heats the plant’s buildings. The inert ash is transported to the plant’s onsite landfill.
A state-of-the-art air pollution control system removes and thermally destroys particulate matter, acid gases, metals, and volatile organic compounds (VOCs) in the exhaust from the furnaces.
The system’s technologies include a Venturi scrubber that removes contaminants via liquid contact and condensation, a spray scrubber system to remove acid gases and additional metals, a wet electrostatic precipitator (Western Pneumatics), and a regenerative thermal oxidizer for thermal conversion of VOCs to carbon dioxide by combustion of gases at 1,500 degrees F. A 125-foot-high exhaust stack assures adequate dispersion of off-gases.
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The lab scene
This elaborate process, and the wide range of performance requirements the plant must meet, are tested, verified, and reported by LaVergne’s laboratory. LaVergne and her full-time crew of Sharon Lawson, Cindy D’Alessandro, and Denise Prouty run grab and composite samples on primary influent, primary effluent, aeration, and final effluent seven days a week.
They also test plant recycle streams and industrial samples required by the pretreatment program. In addition to the normal laboratory procedures for dissolved oxygen, BOD, TSS and pH, the lab group regularly tests for metals, COD, ammonia, total Kjeldahl phosphorus, total Kjeldahl nitrogen, nitrates and nitrites, ortho P, and total chlorine residual.
Quick turnaround and on-site results enable plant operators to tweak processes to make sure all phases of the plant are operating efficiently and effectively. On weekends, a recently retired lab employee, Ann Cohen, conducts tests required for the district’s permit. Only one category of samples is sent out for testing — the toxicity bioassay, which goes to Aquatec Biological Sciences, a commercial laboratory in Vermont.
“Some days the work load seems insurmountable,” LaVergne says, but she admits she loves her job and attacks it with zest: “I’m here bright and early, before 6:30 in the morning.
“Sometimes I’m the manager, sometimes I’m the lab rat. Usually I’m occupied with a little bit of everything. With samples, and paperwork, and testing and reports, I often go home exhausted.”
Still, she manages the milieu with professionalism and compassion. “She’s a very fair boss,” says Lawson. “She understands people and makes allowances for the things that come up in our lives. And she helps us better ourselves by sending us to classes and workshops. It’s a big department, with lots of people and tasks, but she always makes it work.”
Among her many noteworthy achievements, LaVergne is the district representative on the Black-stone River Team project on environmental issues. She also managed the hazardous waste recycling center for the City of Worcester, sets
up all treatment plant tours, and designed a more modern and updated laboratory during the district’s most recent upgrade project.
The lab modernization project included a new ventilation system, cabinetry, bench tops, and other laboratory fixtures. LaVergne’s emphasis on quality and accuracy, together with the EPA’s stringent effluent standards, prompted her search for new analytical equipment.
She acquired an atomic absorption (AA) system (PerkinElmer) for metals, and the EasyChem (Systea Scientific LLC) discrete analyzer for nutrient analysis. The EasyChem and the AA help eliminate delays associated with using outside labs. That allows LaVergne’s staff to perform analyses faster and run tests when needed, especially important with unexpected or non-routine samples. This has greatly improved laboratory efficiency.
“We’re a municipality using taxpayer money, so the first consideration in acquiring new equipment is initial cost and the cost of supplies and maintenance,” she says. “Ease of use and diversity — can it do more than one test? — and life expectancy are also important.”
Glad to be there
LaVergne gladly shares credit for her accomplishments with her co-workers. “I’m part of a great team here,” she observes. “We have employees who give 100 percent, and that’s the key to our success.”
LaVergne earned a bachelor’s degree in biology from Worcester State College. She started as a lab technician for the District in 1978, just two years after the new treatment plant opened its influent gates. She has taken several professional development classes since and has attained the New England Water Environment Association Wastewater Laboratory Analyst Certificate and a Massachusetts Grade 7 Oper-ator’s License.
When LaVergne does manage to get away for a few days or weeks, she loves to travel. “If you ask if I want to go, I’ll say ‘when do I pack?’” she says. Most recently, she cruised the eastern Mediterranean, visiting Turkey, Greece, and the Greek islands.
All things considered, however, she finds her return to Upper Blackstone just as rewarding. “I love my work,” she says. “I always wanted to work in the environmental field, protecting water quality and wild-life. I was really fortunate to get this position. I don’t know what else I would want to do. It’s really the only job for me.”