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Friday, May 10, 2019

Portland Water District’s support of national drinking water week offers tour of facility

By Craig Bailey

On Tuesday, May 7, over 20 people from the community attended a tour of Portland Water District’s (PWD) Sebago Lake Water Treatment Facility. The tour was offered in support of National Drinking Water Week to call the public’s attention to water quality and PWD’s approach to protection, treatment and testing of the water supply to 15% of Maine’s population.

The tour was kicked off by Kirsten Ness, PWD’s Water Resource Specialist, reinforcing her role in protecting Sebago Lake, the number of customers served, the reasons why the lake water is of such high quality and related challenges.

Ness began by stating, “PWD serves approximately 200,000 people across 11 communities. As such, Sebago Lake water quality is of utmost importance.”

https://www.egcu.org/homeNess further shared, “The lake is over 300 feet deep and contains almost 1 trillion gallons of water, which is considered of excellent quality. The lake contains so much water you could fill enough Poland Springs tanker trucks to get to the moon and back - twice!”

The source of water in Sebago Lake comes from the Sebago Lake Watershed, which is more than 50 miles long, stretching from Bethel to Standish and includes parts of 24 towns including the towns of Windham and Raymond. As such, whatever happens in the watershed ultimately impacts Sebago Lake.

Ness reinforced, “One of the reasons for such high water-quality is the watershed is 84% forested, serving as a natural filter. The result: the lake water is clean enough to be exempt from the expensive filtration process required of most surface water sources.”

A key challenge to maintaining water quality is only 10% of the lake is restricted. This results from a law passed in 1913 prohibiting bodily contact within two miles of the intakes and prohibiting trespassing on District lands acquired "for the purpose of protecting the purity of the waters." Later amendments prohibit trespassing within 3000 feet of the intakes.

One of the visitors asked what Ness confirmed was a common question, “Why can we boat within the two-mile zone but not swim?” Ness responded by sharing, “Petroleum products ‘mainly’ evaporate off the surface and our water intakes are deep in the lake. The PWD is more concerned with what we humans carry and excrete.”

Ness further shared, “We have a beach monitoring program and have consistently found that E. coli levels are much lower within the two-mile limit than at swimmable beaches.”

Dave Herzig, PWD’s Plant Systems Foreman then shared an overview of his role in operating the treatment facility as well as additional factors contributing to the quality of water. Herzig mentions, “When we meet with people from other water-treatment facilities we hear common challenges including: shallow lakes, shallow water intakes, algae blooms and rapid changes in river flow. We simply don’t face any of these challenges. In fact, Sebago is protected thermally (via stratification or layers of varying temperatures and densities) nine months of the year. As such, high wind events, pollen bloom and other natural events don’t affect the lake as it does others.”

cstlouis@spurwink.orgDuring the tour of the treatment plant Herzig shared, “In the peak of summer PWD treats approximately 30 million gallons of water per day and during winter around 19 million gallons per day. Treatment occurs in three ways: ozone, ultra violet light (UV), and chloramines.”
Further, Herzig reinforced, “Because our water is so ridiculously clean our treatment facility is a bit over-sized. As a result, we are prepared to effectively handle decreases in water quality should that occur.” The visitors agreed this is a good position to be in!

Mike Koza, PWD’s Lab Manager, shared an overview of his role and led a tour of the lab. Koza reinforced, “PWD tests and monitors the quality of water in the Sebago Lake Watershed, the output of the treatment system as well as numerous sampling sites within the distribution system, containing 1,000 miles of pipe supplying customers.”

Automatic instrumentation is in place which is monitored by lab technicians who also perform lab testing to confirm meter readings. In addition, there are over 45 sampling sites including: fire stations, convenience stores, town halls, post offices, and other readily accessible establishments.
A primary focus of distribution system monitoring is Coliform which, if found, can be an indicator of other bacteria. The good news is that, as Koza states, “we haven’t found any in years.”

Koza responded to questions related to emerging risks that residents along the watershed should be aware of. This includes micro plastics and pharmaceuticals, which can leech into the lake as a result of doing laundry (traces of microfleece have been found in fish from other bodies of water) and flushing (trace amounts of Advil have been found in Sebago).

PWD’s highly qualified lab technicians use leading-edge technology (some of which is locally sourced from IDEXX).

In addition to the tour, PWD is offering a Brewery Collaborative where the public can learn about the connection between forests, water, and beer. Visit pwd.org for a full schedule of offerings and participating breweries.

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