The city of Alma, after nearly a decade of unsuccessfully fighting an algae problem at its wastewater treatment facility, found the perfect non-chemical produced elixir when it adopted a lagoon cover system earlier this year.
Tiles—hundreds of thousands of 22-millimeter hexagonal pieces of high-density polyethylene—are designed to fill with water and float at the top of 9 acres of lagoons that feed into the wastewater management facility, controlling algae growth by blocking sunlight, the energy source for algae.
It takes 2.6 tiles to create 1 square foot of coverage.
The algae problem has been a persistent one for Alma, putting the city squarely in the crosshairs of the Arkansas Department of Environmental Quality on and off since 2013.
Several other algae mitigation systems were researched as a solution, Mayor Jerry Martin said, but none of them provided the certainty of success and the affordability of the tile system.
The tiles, made from recycled material, require no chemicals and Martin has estimated that the city of Alma will save $1.5 million over the next 20 years, or $75,000 per year for a city with fewer than 6,000 residents.
“These tiles are environmentally friendly, they are made with recycled material. It cuts down the costs of chemicals, and also we’re not dumping chemicals into the river now,” Martin said in a television interview.
Floating baffles are being used to keep the tiles in the desired areas, and floating aerators were installed in areas that needed to maintain a required oxygen level.
Previously, the Alma Wastewater Treatment Facility, a series of aerated and facultative lagoons that treat wastewater, required long detention times in shallow water, creating the perfect but undesireable formula for algae growth.
The Alma treatment center implemented several control measures using chemicals over the years, but all were too costly and none were able to satisfy the ADEQ.
Finally, it was determined that a system of covering the lagoons with floating tiles was the only solution.
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