The Passamaquoddy Water District (PWD) is upgrading its water treatment plant in Perry in order to improve the drinking water quality. The project, which costs almost three-quarters of a million dollars, will be mostly completed by the end of May.
PWD Superintendent Nancy Seeley says, "It should be a good filtering system. Our only problem is the source of water. If we can keep the color under control, we should stay in compliance" with drinking water regulations.
According to Mark Deden of A.E. Hodsdon Engineers of Waterville, which is the design and consulting firm for the project, the sand and gravel media in the filtration system are being replaced, which will help with the filtering of the water and with keeping the water turbidity levels lower. In recent years the PWD has violated the federal drinking water regulation on turbidity levels a number of times. Turbidity, or the presence of suspended particles in the water, can interfere with chlorine disinfection and provide a medium for microbial growth.
Also, the plant's outside roughing filter is being upgraded with new valves for each chamber, so that they can be flushed more efficiently. The pre-treatment roughing filter removes about 80% of the water's turbidity, Deden notes. Also, the inside and outside of the filters are being rehabilitated, which will help maintain the metal.
The plant will have new instrumentation for monitoring the water for pH, turbidity and chlorine levels, which will help employees determine what adjustments need to be made to improve the water quality.
Deden comments, "The water chemistry is always changing," with the summer, spring and fall all being challenging times. Because so much surface water is coming into the plant, heavy rainstorms that wash organic matter into the water can lead to the plant exceeding turbidity limits. He notes that the water, after leaving the outlet at Boyden's Lake, runs through swamps and beaver flowages, which increase the levels of organic matter and the water's cloudiness. In 2011 a nearby landowner had opened up a beaver dam, which, along with heavy rains, led to the plant's gravel filter becoming plugged and the issuance of two boil orders for PWD customers.
To also help with the turbidity levels, a chemical consultant with Viking Technologies Inc. has been conducting tests using different chemicals that act as coagulants to help remove organic matter in the water. "It may help when the water's really turbid after a rain," Deden says. "Our goal is to minimize any violations."
In addition, mixers will be installed this summer in the standpipes at Eastport and Pleasant Point in order to lower the chlorine levels in the water. Deden explains that the water in the storage tanks goes in and out at the bottom, and warmer water at the top of the tanks does not get turned over as well. The mixers should help reduce chlorine consumption in the water. Chlorine can combine with organic matter in the water to form trihalomethanes (THMs), which can be carcinogenic. However, the PWD has not had any issues in recent years in complying with maximum allowable levels for THMs.
Upgrades also will improve the energy efficiency of the plant, with new lighting, a more efficient boiler and new main pumps that are smaller. Deden notes that the plant no longer has to pump as much water as it used to, since the water mains in Eastport have been replaced, reducing leakage. While the plant formerly pumped as much as 500,000 to 600,000 gallons a day, now the amount is under 200,000 gallons a day.
Much of the work is being done by Ron Morgan of Pembroke. The project was funded through the State Revolving Fund program, with a total project cost of $730,000. The PWD had received just over $1.5 million in funding in 2013, with the remainder used for water main replacement in Eastport.
Replacement of mains
In addition to the water treatment plant upgrades, the PWD's ongoing water main replacement project in Eastport will continue again this year. The water district has received approval for $1,031,940 in State Revolving Fund monies, with 75% as a grant and a loan balance of $257,985, which will be a 30-year loan at no more than 1% interest.
The project will go out to bid in May. Plans call for replacing 3,700 feet of deteriorated mains on the following streets: Dana, Green, Spear, Prince, Burns, Sullivan, Boynton and Woodman. Work also will include replacing hydrants on most of these streets and installing an 8" valve on Staniels Road.
Once the project has been completed, the water district will have replaced 99% of the mains in the city. "That's quite an accomplishment for us," says Seeley. "We are quite pleased with what we're accomplishing in both places."