INDIAN RIVER COUNTY — A $6.5-million water purification project that will go out to bid in January may help protect southern stretches of the Indian River Lagoon from the kind of environmental disaster taking place north of the 17th Street Bridge.
The PC-South Algal Removal Facility is the swan song of outgoing Utilities Director Erik Olson, who has spearheaded a number of innovative eco-friendly water projects in recent years.
The facility will filter 9 million gallons of polluted water from the south relief canal and 1 million gallons of brine from the south water treatment plant each day, removing thousands of pounds of nitrogen, hydrogen sulfide and other lagoon-toxic substances annually.
Indian River County has about 24 miles of lagoon shoreline.
Seagrass disappeared along three quarters of that reach this year, dooming fish, dolphins and manatees and converting the lower six miles of the county’s estuary into a kind of environmental Dunkirk, the last local stand for hundreds of marine species that make up an ecosystem unique in the world.
“This is important to me,” Olson says of the water project. “It is one arrow in the quiver we can use to help protect the lagoon.”
Olson and Capital Projects Manager Mike Hotchkiss began thinking about a south county water-treatment facility because the Florida Department of Environmental Protection has ordered utilities to stop discharging into the lagoon brine left over when drinking water is purified.
Many counties and municipalities have chosen to dispose of the brine by injecting it into the water table through deep wells, but Olson wanted to maximize environmental benefit while meeting regulatory requirements.
“We try to think creatively, to get outside the box and deliver multiple benefits with one project,” he says. “What we are doing does not cost any more than an injection well that would just get rid of the brine, but it does much more.”
The main facility will be built south of 5th St. SW, between Old Dixie Highway and 20th Avenue, next to the Oslo Road Water Treatment Plant.
A pump station on the bank of the South Relief Canal a mile or so away will pump canal water to the facility where it will pass over a bed of algae that consumes nitrogen and other substances before flowing back into another canal and eventually into the lagoon.
“The algae-scrubber technology is a patented, proven process,” says Olson. “What we had to do to get this permitted with the DEP was fit the system into our site and show that it would work the way we said it would.”
“We built a small pilot project and monitored that for a year to show the DEP how it would work,” says Hotchkiss.
The algae will grow on an inclined concrete slab approximately 350 feet wide by 625 feet long.
Header works will evenly distribute the flow of water over the slab and a settling basin and miniature wetland at the other end will provide additional purification before cleansed water flows back into a lateral canal that connects to the main south canal.
Nitrogen, which comes from fertilizer runoff and other sources, damages the lagoon by feeding the growth of algae that consumes oxygen and makes water murky and slimy, cutting off sunlight to sea grass and starting a domino effect of ecological degradation.
In Olson’s ingenious project, algae consumes the nitrogen before it gets in the lagoon.
“We will have to rake the algae off every few weeks,” says Hotchkiss. “It makes good mulch to feed plants in our parks.”
The process gets rid of the brine problem through dilution. Salt still enters the brackish lagoon, where salt content is about 25 parts per 1000, but not in harmful concentrations.
“We have already purchased the land, so that is done, and we have our permit for industrial waste from DEP,” says Olson. “We are building the project in what was an old citrus grove so it is not an environmentally sensitive area.
“We plan to go out to bid in January and have the facility operational by next summer.”
The county opened two similar water purification projects in 2010 under Olson’s leadership.
The Spoonbill Marsh off of 57th Street mixes lagoon water with brine from the north county treatment plant and then filters the combined water through a natural marsh populated with 1 million oysters.
The Egret Marsh in West County does not deal with brine. Its sole purpose is to clean up canal water by pumping it over an algae bed like the one soon to be built in South County.
“The new project combines features of the Spoonbill and Egret Marshes,” says Olson. “Hopefully, we will be able to think up a nice picturesque name for it.”
Olson will retire at the end of November but says he is confident Hotchkiss and new Utilities Director Vincent Burke, will successfully complete the project and continue the department’s innovative and ecology-minded ways.
Burke comes to the county job from a facilities management position at Harbor Branch Oceanographic Institute, the leading environmental research organization on Florida’s Central Atlantic Coast.
