 |
| A free virtual tour of the Sebago Lake Water Treatment Facility in Standish will be conducted from 5:30 to 6:30 p.m. Tuesday, May 4 on Zoom. Registration is required. SUBMITTED PHOTO |
The Portland Water
District is a century-old company, rich in history and experience. That
tradition forms a solid foundation for delivering quality products, while
forward thinking provides innovative approaches to combat emerging issues
within the industry. It is an independent quasi-municipality, serving nearly
200,000 people – 50,000 customers – in 11 Greater Portland communities. PWD
delivers water service to Falmouth, Raymond, Scarborough, South Portland,
Standish, and Windham, and provide both water and wastewater service to Cape
Elizabeth, Cumberland, Gorham, Portland and Westbrook.
The virtual tour of the Sebago Lake Water Treatment Facility runs from 5:30 to 6:30 p.m. Tuesday, May 4 on Zoom. To register, sign up at pwd.org or call 207-774-5961 ext. 3336 by May 3.
During the virtual tour, visitors will learn about the treatment and laboratory processes used to transform Sebago Lake’s water into the high quality, safe drinking water you enjoy at the tap. The tour will include live discussions with PWD staff and is geared toward an adult audience. Registration is required and a Zoom link will be emailed to registrants.
Also in May, starting on Sunday, May 2, visitors to www.pwd.org will be able to explore the district’s “Forever Forests for Sebago Lake project” online.
For more than a decade,
PWD has supported the purchase of forested land in the Sebago Lake Watershed.
These forests filter your drinking water while also providing other benefits we
can all enjoy, like hiking, birding, kayaking, and hunting. Explore conserved
properties through the link online to “Forever Forests for Sebago Lake” Story
Map!
The Sebago Lake Water Treatment Facility is located on a
10-acre site near the intersection of Route 35 and Route 237 in Standish. This
facility began treating water in February 1994 using ozone, a powerful
disinfectant that kills potentially harmful microorganisms and is 99.99 percent
effective against viruses and Giardia.
Treatment includes screening, ozonation, UV light treatment,
chloramination, and corrosion control. Also as a result of a citizen
referendum, fluoride is added to the water at the plant to promote dental
health.
The federal Safe Drinking Water Act was amended in 1986 in
response to concerns about drinking water quality throughout the country. The act
required that drinking water from all surface water supplies be filtered. PWD applied
for and obtained a waiver from this filtration requirement because of the
exceptional water quality of Sebago Lake and the district's comprehensive
watershed protection program. This saved customers about $20 million to $50
million in capital costs required to construct a filtration plant.
Many other aspects of drinking water quality were addressed by the Safe Drinking Water Act amendments including new standards for disinfection. Disinfection is the destruction of disease which causes organisms such as bacteria, viruses, and Giardia.
The District chose to switch from chlorine to ozone for
primary disinfection to meet these requirements. Ozone works in much less time
than required with chlorine. Using chlorine alone to meet the new disinfection
requirements would have increased the formulation of chlorinated by-products
which at high amounts are potential health threats to water consumers.
The Sebago Lake Water Treatment facility was the first
free-standing ozonation plant to be built in New England and the first in the
country to meet the disinfection requirement of the Surface Water Treatment
Rule with ozone alone. A state-of-the-art laboratory is on site and conducts
water quality testing for the lake, treatment process, and distribution
systems.
A $12-million project to update the ozone disinfection process
and install a new UV water treatment system was completed in 2014. This
sustainable, forward-thinking process design incorporated a new UV system into
the existing plant, allowing the district to receive a $300,000 competitive
grant from the Efficiency Maine Trust Competitive Program. As a result of these
energy efficient upgrades, an annual electricity cost savings of $150,000 is
expected.
During the UV water purification process, water is sent
through units equipped with UV lamps. As the water is exposed to the UV light,
molecular bonds in the DNA of viruses and bacteria are broken down, rendering
the bacteria harmless and unable to reproduce. Chloramines are added in the
pipeline after UV treatment to provide long lasting disinfection in the water mains.
Other additives are also used to help reduce corrosion. Treated water flows
from the clear well into the transmission mains.
To avoid adding ozone pollution to the lower atmosphere,
blowers draw air out of the enclosed contact tanks through special equipment
which converts any leftover ozone back to oxygen. The "ozone-free"
air is then discharged to the atmosphere.
UV disinfection is a purely physical process which is proven
to be more effective, reliable and environmentally friendly than chemical disinfection.
Large electrical generators are located at the facility so that pumping and treatment can continue even when the power fails. <
No comments:
Post a Comment