Combining Adaptive Management with Alum and Phoslock, the Long Lake Story

Today started the first phase of the Long Lake Adaptive Management Program to help correct years of toxic algae blooms.  The lake is a 330 acre water body in Thurston County Washington.  It has experienced closures for toxic algae blooms over the year including recent summer seasons.  They were looking for a solution that would help mitigate the problems that cyanobacteria cause including lake closure.

Phosphorus is a key driver of cyanobacteria blooms.  When levels are high, these species have a competitive advantage over beneficial algae species because they can fix nitrogen from the atmosphere.  Removing phosphorus as a source in the water column limits the carrying capacity of the lake to produce these blooms.

There has been a school of thought over the years that expensive studies are necessary to come up with plans to fix these problems.  These generally result in costs that would often go a long way toward actually mitigating the problem.  After the study is performed, work proceeds to implement the recommendation of the studies and these often claim they will last for years.

Recent examples are aluminum sulfate treatments designed to “reset” the lake and cap lake sediments, a primary source of phosphorus loading in many lake systems.  These are also generally expensive ventures and while they are “designed” to correct problems for decades, they generally last well short of the lifespan assumed in the study.

Adaptive management is a concept that can be implemented at a much lower cost.  Initial data collection and stakeholder input is reviewed.  If there are data gaps, then those are identified and additional sampling occurs.  With that information, a prescription is developed to alleviate the problem, the prescription is implemented and follow-on monitoring tracks results.  As results are known, additional follow-on work can be suggested and implemented.

The Long Lake prescription was designed to utilize two different phosphorus sequestering technologies.  The first application is happening this week.

Our biologists are using Aluminum Sulfate to target and sequester the phosphorus available in the lake water column.  This will remove much of the P load that would fuel algae growth in the early and mid-summer months.   A video of the alum floc forming behind the application vessel can be viewed here: https://youtu.be/FFMACktYu4M

A second application will be made this coming week with Phoslock.  Phoslock is a phosphorus sequestering technology that was developed by the Australia Government to combat Harmful Algae Blooms (HAB) and reduce the threat of waterborne toxins to pets, wildlife and human health.  This technology is different that aluminum sulfate.  The Phoslock captures free reactive phosphorus present in the water column and converts it to a mineral that will remain inert.  Phoslock also caps the lake sediments effectively.

In this case the Phoslock application will target the lake sediments below the thermocline where during the summer months anoxic conditions can lead to sediment phosphorus release.

Ongoing monitoring will adjust the program as necessary over the coming years.

The result of this program is forecast to be significantly less than many similar projects in the Pacific Northwest.

Is “Bio-Dredging” a thing? Yes it can be

Lakes and ponds are the lowest point in the watershed and over time can fill in with deposits of rich organic sediments.  Over time, these sediments are an accumulation of dead aquatic weed and algae growth, fish and other organisms and become a sink for nutrients that can cycle back to the water column and fuel additional growth degrading water quality.

Removing this organic build up is often required to restore water quality and to add depth to the pond.  Conventional dredging can be problematic in urban settings.  There often is not room to pump dredge spoils in a HOA or golf course pond environment.

Our mapping systems can determine lake sediment composition, the lighter colored areas show organic sediment accumulation

One solution is to enhance the natural processes to digest this organic matter and increase water depth.  This can be accomplished by our biologists using a combination of Nanobubble Technology and the addition of Probiotic natural bacteria cultures.

A nanobubble generator deployed to lake to increase sediment oxygen levels

Dissolved oxygen levels in organic lake sediments is generally very low to zero.  Dissolved Oxygen is key to the success of aerobic digestion of these organic sediments.

Nanobubble generators deliver high levels of dissolved oxygen right to the sediment interface and the interstitial waters within the sediments.  These generators pump water from the lake though the nanobubble generator and inject nanobubble rich water back into the lake.  Nanobubbles are very small, on the molecular level, and they are negatively buoyant and sink to and into the sediment layer throughout the lake.  They then attach and burst delivering dissolved oxygen right into the sediments.

Sediment oxygen levels rise dramatically after installation of nanobubble generator and increase digestion of organic sediments

We install either a temporary or permanent Nanobubble Generator at the lake sized to the volume of the lake

We then apply Naturalake BioSciences MuckBiotics pellets evenly across the targeted area monthly.  MuckBiotics pellets saturate the sediment layer with rare earth stimulants and a broad spectrum of natural aerobic bacterial cultures.  This accelerates the digestion of organic matter

MuckBiotics pellets are then applied monthly to increase the speed of sediment digestion.

We measure the reduction in sediment depths over time to document the recovery of the lake from the impact of accumulated sediments.  This process will not reduce deposition of sand or soils, but can greatly benefit the lake and avoid having to physically dredge organic sediments to restore water depth and lake health.

Our biologists can design a program that meets your needs.  Please reach out if your pond needs remediation of organic sediments.

We also work with conventional dredging equipment when this approach isn’t suitable for your situation.

Nanobubbles for Lake Restoration and Algae Management

For decades we have known that providing dissolved oxygen to the lower layer of lakes can improve water quality.  Lakes can stratify thermally in the spring and summer months isolating the lower layer from the atmosphere.  When that happens, aerobic bacteria can consume the dissolved oxygen that is trapped there in short order and that causes a number of chemical and biological changes to occur.  The primary method of solving this problem has been aeration.

In the last year Nanobubble generators have burst onto the scene.  These systems pump water from the lake into the generator and return water laced with Nanobubbles to the lake.  Nanobubbles are extremely small and negatively buoyant.  About 2,000 of them are smaller than a grain of sand.  These bubbles disperse through the lake.  As they “bump” into organic material, they attach and burst delivering oxygen.  This action will also cause a hydroxyl radical to form and that chemistry can oxidize algae cells and the toxins they may produce.  This can provide 24/7 algae control and over time supplement other lake management activities.

Nanobubble Algae Management Study at ASU

Another unique feature of this type of control is that you can oxygenate the lower portion of the water column without disrupting the thermal stratification that is occurring.  This can provide refuge for fish in the cooler deeper waters.

Aquatechnex can provide a Nanobubble system sized to your lake.  These can be sold directly to your orgainzation, or they can be part of an overall lake management program we perform for you with a set monthly fee.  For more information please get in touch at [email protected]

New HAB/Toxic Algae Monitoring and Response System

This buoy measures chlorophyll a and the pigment that is unique to HAB Blue Green Algae and uploads to the Cloud every 15 minutes. We can monitor your lake from our computer or phone and respond

Aquatechnex biologists have deployed the first of many algae monitoring buoys for our clients in Southern California.  This system measures a number of water quality parameters and reports via onboard cellular system every 15 minutes.  Two of the key parameters measured are Chlorophyll a with provides a measure of algae biomass and Phycocyanin which is a pigment that is unique to Blue Green Algae species.  Blue green algae or cyanobacteria are toxin producers that cause significant problems in our nations lakes and reservoirs.

Every day we examine conditions in these lakes remotely.  When we see Chlorophyll a or Phycocyanin levels increase, we mobilize treatment teams to target and control that growth before it becomes a full blown bloom or toxin producing event.  This allows us to be more proactive and responsive in our mission to keep your lakes free from toxin producing conditions.

To sign up for this service please fill out our contact form and we will get with you shortly.

Good Article on our work at Ketchum Lake

Ketchum Lake has been one of the more prolific algae toxin producing lakes in the state of Washington.  Aquatechnex biologists were brought in to implement an ALUM treatment program that focused on sequestering phosphorus.  This project has been very successful.  For additional information on this project and results go to the County Web Site at http://snohomishcountywa.gov/2451/Lake-Ketchum-Restoration

Gene Williams also presented this work at the Washington Lakes Protective Association meeting in Walla Walla this week with his paper titled “A new life for Lake Ketchum, Restoration of a hyper-Eutrophic Lake”

 

Phoslock Work Continues to Impress

Free Reactive Phosphorus drops to near below detection

Aquatechnex pioneered the use of Phoslock technology to improve water quality in Western US Lake Systems starting in 2010.  We have treated over 20 water bodies with similar results, a dramatic reduction in Phosphorus available in the water column to sustain toxic algae populations.

The latest project in Southern California continues this trend.  Our team has been combating cyanobacteria blooms in this lake for a number of years using conventional treatment technology.  While applying US EPA registered algaecides provided relief, this was more of a reactionary approach to the situation.  The team had to monitor algae levels and target the lake for treatment when cell count and/or species shifts to blue greens indicated the lake was beyond management thresholds.

This May Phoslock was applied following a management plan developed for the lake.  The application took approximately four days to complete.

Sampling results in the months since look extremely promising.  We have noted no problem algae blooms and the algae that is present is beneficial.  Transparency has improved dramatically.  Total phosphorus levels have dropped dramatically and continue to trend down.  The ortho or free reactive phosphorus has seen a dramatic drop.

We will continue to monitor and report on this project as time goes on.