September 19, 2016 01:58PM
By Andrew Ragali Record-Journal staff
MERIDEN — A floating partition was installed in Bradley-Hubbard Reservoir this summer to prevent algae growth that has caused the city’s drinking water to have a foul odor and taste. The city is also treating the reservoir with copper sulfate to help get rid of the algae.
Public Utilities Director Dennis Waz said algae growth in the reservoir, located in Giuffrida Park, has hurt water quality. Due to high levels of nutrients, such as nitrogen and phosphorus, blue-green algae is thriving. The persistent problem has led the city to seek help from a scientist with expertise in the area.
Waz said there was a “fairly large” bloom in the reservoir about a month ago. Oils released by the algae cannot be removed from drinking water during the treatment process, and cause taste and odor issues that have prompted complaints from residents, he said.
A few months ago, the city installed a floating partition in the reservoir. The partition drops down about 8 feet into the water, but doesn’t reach the bottom of the reservoir, according to Waz. As the water moves south toward the intake to the Bradley-Hubbard water treatment plant, it travels under the partition. This aids in mixing the water and “prevents stratification,” Waz said. Stratification occurs when layers of material, such as algae, form in water and prevent it from mixing. Blending allows for the intake of a more homogeneous water mixture which doesn’t have a foul odor or taste.
“This is one step to improve water quality,” Waz said.
While the partition has never been used at Bradley-Hubbard Reservoir, he said, it has been used with success in Broad Brook Reservoir.
Waz said the water department is also treating the reservoir with copper sulfate to help prevent the growth of algae.
“The whole goal here it take every step we can,” he said, noting the city is looking to use the least amount of chemicals as possible to solve the problem.
The city hasn’t had to use copper sulfate to treat Broad Brook Reservoir, Waz said. To date, the algae problem at Bradley-Hubbard Reservoir has improved since treatment began this summer. Water department employees apply copper sulfate to the algae directly using a boat and agricultural sprayer.
Waz said water utilities across the state and country are dealing with similar issues related to algae. The extended heat wave and lack of rain this summer have likely played a part in causing a larger than average algae bloom, he noted. The nutrients that are promoting the growth of algae are naturally occurring due to the landscape and location of the reservoir, Waz added.
While blue-green algae isn’t uncommon, it can be problematic depending on the size of the bloom, said Chris Bellucci, supervising environmental analyst for the state Department of Energy and Environmental Protection.
Algae blooms cause water to turn a “pea soup color green,” he said. “That happens usually later in the summer, about now into fall. Usually weather conditions can play a part in that.”
The size and regularity of algae blooms also depends on the age of a water body. Just like a forest goes through phases, water bodies can change over time, Bellucci said. Blooms can occur if the water level changes, or if there are a build up of sediments that contain nutrients.
Waz said his department tests Bradley-Hubbard Reservoir weekly to ensure the water is safe. Algae can produce toxins that are harmful to humans, according to Bellucci.