Articles 6 Dec, 2021

Algae-Free in Four Weeks: How the City of Archie Stopped Algae Blooms

An unexpected bloom

This year, Rick Blundell, Water Superintendent for the City of Archie, installed one of our ultrasonic systems in his 5.5-foot surface-acre reservoir located in Missouri. Back in the winter, the City of Archie experienced a hard freeze that lasted for about two and a half weeks. When ice formed over the reservoir, Rick thought: “We’re going to have some really nice water this year.”

What he didn’t realize was that there was an algae bloom occurring at that time. As soon as the ice melted away, within only two weeks, the water went from clear up top to extremely cloudy, to the point that you couldn’t see clearly within a foot into the water.

That’s the moment the City of Archie decided to purchase an MPC-Buoy. On August 3rd, after they’ve already had a couple of treatments with copper sulfate and didn’t see the results they were expecting, they finally deployed the Buoy. Within only four weeks, their turbidity levels coming into the water plant improved.

History of turbidity in the lake

When the algae bloom occurred, turbidity levels in the water plant’s primary settling basin reached 1.3 NTU (Nephelometric Turbidity Unit). This was hard for the filters because they were already over-burdened with their rapid gravity and sand filters. Their filter turbidities went from 0.05 to almost 0.2 and, from time to time, slightly above it.

Four weeks after the MPC-Buoy was installed, Rick’s operator told him that the turbidity levels going into the water plant went down from about 1.3 to about 0.04, which was really good.

Turbidity levels going out of the treatment plant dropped significantly below 0.1. A couple of weeks later, turbidity levels in the water returned to their normal levels of 0.2 to 0.25, which they normally get at the beginning of spring.

Seeing clearly for the first time 

When this occurred, Rick noticed that he could see clearly through the water anywhere between 3 and 5 feet, depending on whether the wind was blowing or not. Not only that, but the moss that was growing on the rocks at the edge of the lake was also dying off. This encouraged the City of Archie to allow fishing in the lake.

At this point, the daily usage of water had gone up, on average, to about 10,000 gallons a day. In the past, they used to run between 75,000 to 100,000 gallons a day. Rick says, even if they’re not saving money on chemicals, they’re gaining money on sales: “I don’t know what else to say other than the fact that I am happy. The state is happy.”

After hearing about the MPC-Buoy technology and the positive results, at the end of August, the city sent one of their field managers and one upper-level manager to the lake:

“As he looked at the lake, he was literally dumbfounded. He said: ‘You’re telling me this lake has been looking like this since you’ve installed that?’” To which Rick replied, “Yes. If you would’ve been here four weeks ago, you wouldn’t be able to see a foot in the water because the algae were so thick.”

In the past, Rick and his team tried adding carbon and potassium permanganate, but they couldn’t get rid of the algae in order to bring their turbidity levels down. Once the MPC-Buoy was installed, the carbon and the permanganate were “pretty useless,” Rick recalls. They were still adding them but would eventually take them offline, except for the carbon.

What caused the algae blooms?

Oftentimes, algae blooms are a result of nutrients like phosphorus and nitrogen coming from fertilizer runoff. These nutrients enter an aquatic ecosystem and fuel the growth of algae. Add sunlight and stagnant water into the mix, and you get a harmful algal bloom.

“One thing I do want to point out is this: we over here in Archie, for the last 30-40 years, have been struggling with our disinfection byproducts because of the amount of organic matter that gets into our basins […] We have to treat out the Grand River, which is where we pull our water from; is the line for the next 30-40 miles with crop fields. And every spring, they spray chemicals on their plants. When we get rain, it washes into the Grand River. So, the River, at times, is so green that you’d think somebody painted the water. It’s so nutrient-rich and we pull that water and put it in our impoundment.”

By controlling algal growth, the MPC-Buoy improves the overall water quality, allowing for safe and clean water to be drawn from it.

“Because of this technology, we’re finally going to be able to do something that hasn’t been done in 40 years and that is get these DPBS (disinfection byproducts) under such control that the state has been wondering if I’m cheating on my lab tests, which we are not […] and it seems like finally, Missouri DNR (Dept. of Natural Resources) is actually happy with the City of Archie, so I’m kind of excited about that.”