Loveland hopes to mitigate algae blooms in water supply

Green Ridge Glade Reservoir

From The Loveland Reporter-Herald (Craig Young):

Employees of the city department that fielded 600 complaint calls last fall about the smell and taste of Loveland’s tap water told the City Council on Tuesday what they have done to avoid a repeat this year.

The unpleasant “earthy, musty flavor,” which was caused by a bloom of a particular algae in Green Ridge Glade Reservoir, was particularly bad in 2015 and 2016, city water quality analyst Tim Bohling told the council during its study session.

Hot weather at the end of the summer helps the anabaena microorganism grow profusely, he said, and Loveland Water and Power wasn’t able to use the copper sulfate algaecide it formerly used because of new water-quality standards from the state health department.

The hydrogen peroxide-based powdered algaecide the department threw at the anabaena in the place of the copper sulfate seemed to work at first, Bohling said, but it eventually turned out to be ineffective.

“As we know and experienced, anabaena is a very, very extreme odor and taste producer,” he said.

Bohling said the city hired a consultant to look at the problem from a number of angles.

The potential fixes included using sound waves to kill the algae and send it to the bottom of the reservoir and adding oxygen to the water, but the staff settled on buying simple solar-powered devices that mix up the water to disrupt the growth of the algae.

The anabaena is unusual in that it can adjust its depth in a lake to a level that is ideal for its growth, he said, and using the Medora SolarBee mixers defeats that ability.

For $202,000, the department bought four of the mixers, which should just handle the 160 surface acres of the reservoir when it’s full, Bohling said.

Among its other strategies to fight the problem, Loveland Water and Power will look at adjusting the level from which it pulls water from the reservoir to find the sweetest-tasting spot, he said.

The department also will conduct a $30,000 study in August, when algae start to bloom, on the best way to use powdered activated carbon in the water treatment plant to fight the smell and taste problems on that end, he said.

Several council members thanked the Water and Power staffers for their presentation and for their approach to dealing with a problem that has caused so much public concern.

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