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Water treatment PAAS plant on lookout for algae toxins

2014-08-06 10:55:54

 The algae-induced toxin scare that forced Toledo residents to turn off their water taps on the weekend has prompted the Union Water System to sample the water it gets from Lake Erie much more frequently.

“Because of the concerns of what’s been happening in the southern end of the lake, we’ve decided to ramp that up,” the system’s general manager Rodney Bouchard said Tuesday, adding that so far this year there have been no algae issues whatsoever for Union Water, which serves 56,000 residents in the Kingsville-Leamington area.
The wind has historically been Union Water’s friend, keeping the blue-green algae blooms that often originate in the southwestern corner of the lake away from its intake pipes west of Point Pelee, Bouchard said. On a weekly basis, Union Water sends samples to a lab to test for the toxins associated with blue-green algae, including the microcystin whose high levels prompted the Toledo shutdown.
Because of what’s happened in Toledo, Bouchard said he’d like to send samples to the lab every day, or at least three to five times a week, “to get an idea of what’s going on and if (the algae bloom) does start coming our way it will give us a bit of a heads up.”
The highest reading locally for these microtoxins in untreated water has been 1.7 micrograms of microtoxins per litre, which happened only once a couple of years ago, said Katie Stammler, a water quality scientist with the Essex Region Conservation Authority.  The level of concern, as far as the Ontario government is concerned, is 1.5.
“And our drinking water systems are completely capable of handling what we’ve already seen,” she said. “When water comes out of our drinking water plants, it’s below detection for microcystin.”
The water warning was issued in Toledo Saturday following sample readings at Toledo treatment plant showed the presence of microcystin, causing concerns about possible liver and kidney damage. After multiple tests on the weekend showed the levels had dropped to safe levels following intensive treatment, Toledo’s mayor declared the water safe and took a  ceremonial sip.
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“The levels of microcystin that they were seeing in Toledo, we haven’t seen anywhere close to that, so there’s not a need to raise alarm bells or anything,” Stammler said.
Windsor has not had any issues with blue-green algae entering its water system, according to Garry Rossi, director of water production for the Windsor Utilities Commission. WUC, which also provides water to Tecumseh and LaSalle, gets its water from the bottom of the Detroit River — deep in the shipping channel —  where algae blooms do not happen.
“To date, we have no indications of any issues with microcystin in the water,” Rossi said.
While algae blooms occur “minimally” in Lake St. Clair, the big concern is in the western basin of Lake Erie, according to ERCA’s Stammler. The local water systems that get their water from Lake Erie include Wheatley, Pelee Island, Union Water and the Colchester-Harrow system, which is currently shut down for repairs and is getting its water from Union Water.
The blooms are principally the result of high phosphorus levels in the lake. Those high phosphorus levels come from agricultural fields (fertilizer) and urban sources such as sewage treatment plant discharges, lawn fertilizer runoff and detergent draining into storm sewers, Stammler said. And when there is  more phosphorus than the system can handle, it feeds the algae and the algae produces these toxins.
The problem is more acute in the Toledo area because the Maumee River that runs through Toledo and empties into Lake Erie is a primary source of phosphorus.
“We have a smaller output of phosphorus and we have smaller algae blooms here and a lot of what we see is blown over from the Maumee as well,” said Stammler.
What happened in Toledo should serve as a “teachable moment” for the policy makers around the Great Lakes, said Derek Coronado of the Citizens Environment Alliance. The solution is to focus on pollution prevention, he said.
“We’re collectively the source of the problem.”
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Union Water’s Rodney Bouchard said when there is algae in the water, there’s a visible green tinge in the raw water as it enters the treatment plant. “We really haven’t seen that this year,” he said.
He said the system is involved in a three-year study that uses an instrument to continually monitor the water for 13 different properties, including blue-green algae, serving as an early warning system for any problems. He said special measures are taken long before the readings hit 1.5 micrograms per litre.
The protocol involves sending more samples to the lab to differentiate what types of microcystin they’re dealing with, stopping a pre-chlorination step used to deal with zebra mussels that helps release algae toxins, ramping up a coagulation process that captures and settles algae cells, and turning up the powdered activated carbon system that captures a lot of organic toxins.
“We ramp all these up to higher levels and then we follow with a full sampling program to make sure nothing gets through into the finished water,” Bouchard said.
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