Lake St Charles CDD has been awarded a $586,550 grant from the Florida Department of Environmental Protection for Innovative Algae Control and Phosphorus Abatement in Lake St Charles.

Lake St Charles CDD has been awarded a $586,550 grant from the Florida Department of Environmental Protection for Innovative Algae Control and Phosphorus Abatement in Lake St Charles.

The grant fully funds many state of the art and groundbreaking technologies that will dramatically increase the water quality in the the big lake. The grant / study period began July 1, 2021 and will conclude October 1, 2022. At the conclusion of the grant, the equipment and installations will remain and continue to be operational. 

 The Project’s innovative combination of green technologies was selected for treatment durability and cost effectiveness in contrast with dredging the lake. This “green” approach is designed to be less disruptive to the ecosystem and prevent the detrimental environmental effects of long-term traditional algae treatments which can result in copper build-up in the sediments leading to a sterile lake bottom. A sterile lake bottom will lead to a lack of beneficial bacteria and cause among other things, high algae blooms. Lake St Charles is a hypereutrophic headwater for the Archie Creek (WBID 1628) and Archie Creek (Tidal) (WBID 1628A) watersheds, finally connecting to Tampa Bay. The State of Florida has made significant investments to restore Tampa Bay. In aggregate, those investments will be defended in similar headwaters across the Tampa Bay Watershed, many of which face similar issues of harmful algae blooms, low dissolved oxygen, and high nutrient loading. 

The lake is the namesake and a significant amenity of the community. Strategically, Lake St Charles CDD seeks to develop a strong model for community water quality management by using innovative technologies, the broad application of which will benefit all Floridians.

There are four technology  components to the project that will be sequentially introduced approximately  every 3 months.

These technologies include LG Sonic’s MPC-Buoy, MPC-NanoBubble, Phos-Out Mat and Vertex's bottom diffused aeration.

The first implementation are the two LG Sonic solar powered buoys that are now positioned on the lake. This technology comes from the Netherlands and is used around the world to chemically free control algae in water bodies used for human consumption. This is only the second use of this technology in the state of Florida. The buoys are outfitted with 360 degree directional ultrasound devices and an extensive array of water quality testing instruments that continuously monitor nitrogen, phosphorus, turbidity, water temperature, dissolved oxygen, pH, green algae and blue-green algae. The real time data is transmitted to a central office every 10 minutes where analyzing algorithms can predict an algae bloom and engage immobilizing ultra sound treatment a few days before its emergence. The ultrasound creates a sound layer in the top layer of the water. The sound layer prevents the algae from rising to the surface to get sunlight, the algae will sink to the bottom of the lake and are degraded by the bacteria present.

The ultrasound wave is not harmful to any aquatic life other than algae.

The next technology to be implemented is Vertex's bottom diffused aeration that uses the rising force of millions of air bubbles to transport lake bottom water to the surface, allowing oxygen to be absorbed and circulating the entire water column. There will be 30 air diffusing stations dispersed throughout the lake circulating  an estimated 152,263,853 gallons of lake water.

This system is expected to reduce nutrient levels and associated algae growth, reduce bottom muck and reduce aquatic midge and mosquito insect hatches. 

The third component will be the introduction of LG Sonic's MPC-NanoBubble technoogy. This infuses infinitesimally small bubbles of pure oxygen into the water increasing the dissolved oxygen levels. The bubbles are so small that they remain in the water for week or even months until they are used up by aquatic life or sink to the bottom and bind with sediment phosphorus molecules rendering them inert. Thus decreasing the "fertilizer" that fuels algae growth.

Finally, Phos-Out Mats consisting of a combination of synthetic fabric and open structure – activated carbon PE foam will be installed. The foam mats are installed just above the sediment and can float up like a seaweed due to the use of buoyant materials. This unique design can successfully adsorb phosphorus because dissolved oxygen levels above the sediment are higher and the mats provide a large contact surface but do not cover the sediment itself. The foam mats have been designed to quickly adsorb available phosphorus from the sediment but continue to be effective even after the initial binding capacity has saturated. 

As a requirement of the grant, a public presentation  will be conducted via zoom where these technologies and the anticipated results of their implementation will be discussed. There will be a live question and answer component with the experts at the end of the presentation.  It is anticipated that this will take place in the second week of August. An announcement and a link to log into the live zoom meeting will be posted on the  Lake St Charles App and the LakeStCharles.org website in the next few weeks.

 

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