Standing on the shoreline of the L-shaped “makeup water pond” at Stanton Energy Center, Tom Gaboian looks out over the body of water OUC’s power generation units rely on for coolant. Out in the distance, two small flags rising above pond waters are barely visible on the tranquil surface.
However, to Gaboian, SEC Power Plant Engineer, what is clearly noticeable is what’s not floating on the 93-acre, 500 million-gallon pond – algae. Gaboian is hopeful he has seen the last of algae blooms on the pond since working with Charles Linder, Supervisor of SEC’s Water Lab, on a proposal to deploy a device that fights algae with ultrasonic soundwaves.
Algae has been an unrelenting nuisance in the power plant’s cooling system since the facility opened in 1987. Containing high levels of total suspended solids, algae can diminish heat transfer as pond water — about 8 million gallons a day on average — flows through condenser tubes and condenses turbine exhaust steam. Simply put, the aquatic weed can gum up the works at Stanton.
Hanging a foot underwater from floats that would be all but invisible if not for the small flags marking their anchored locations, two DB-Quattro units, each about the size of a bread box, wage subsurface electronic warfare on two species of algae. The devices’ ultrasonic soundwaves zap the buoyance out of blue-green and green algae within 400- and 150-meter radiuses, respectively, without harming other marine life.
“The ultrasonic soundwaves destroy gas vesicles in algae, keeping it from floating to the top,” said Gaboian. “If algae can’t get to the surface, it can’t photosynthesize and thrive.”
Each device is powered by 60 watt solar panels mounted on the water’s edges. During daylight hours, the solar systems also charge batteries to keep the algae-killing machines working in darkness.
With the introduction of the DB-Quattro units made by Hydro-BioScience®, OUC may be able to reduce or eliminate the use of algaecides on the pond. The annual cost of chemical treatments runs more than $14,000.
“If we’re able to eliminate algaecides altogether, these devices could pay for themselves in a little over a year,” Gaboian said, adding the entire project cost about $20,000.
The Stanton pond is supplied with reclaimed water drawn from Orange County’s Eastern Wastewater Treatment plant, reducing OUC’s demand on groundwater supplies. As a zero liquid discharge facility, Stanton uses and re-uses wastewater that could otherwise end up in the Econlockhatchee River.
Daniel Haddad, Manager of Power Plant Engineering at SEC, commended Linder and Gaboian for identifying a low-cost solution to a chronic problem.
“These devices have been around for a while, but I don’t know if other utilities have used them to combat algae in their makeup water ponds,” said Haddad. “Tom and Charles did the homework on them and we decided to give them a try because their cost wasn’t prohibitive. So far this project is working out quite well.”