Freshwater Lake Treatment: 4–6 Acres
Maintaining good water clarity and water quality is especially important for freshwater lakes used for drinking water, recreation, and other community purposes.
Freshwater systems continuously receive organic material from vegetation, runoff, sediment, and other natural or human-related sources. Over time, this material can accumulate on the lake bottom and contribute to increased nutrient availability.
Seasonal Nutrient Release and Algae Growth
During the spring and fall, changing water temperatures can cause lake turnover and increase the movement of nutrients throughout the water column.
At the same time, decomposition of accumulated organic matter may release additional nutrients from bottom sediments.
These conditions can contribute to:
- Excessive algae growth
- Reduced water clarity
- Increased turbidity
- Organic solids accumulation
- Unpleasant odors
- Lower dissolved oxygen levels
When algae populations grow rapidly and later die, the dead biomass becomes additional organic material that must be decomposed by microorganisms.
How Algae Decomposition Affects Dissolved Oxygen
Heterotrophic microorganisms consume oxygen as they break down dead algae and other organic material.
When large amounts of biomass decompose at the same time, dissolved oxygen (DO) levels can decline significantly.
Surface waters with dissolved oxygen concentrations below approximately 2 milligrams per liter (mg/L) are considered hypoxic. These low-oxygen conditions can stress aquatic organisms and, in severe cases, contribute to fish and other aquatic life mortality.
Low-oxygen conditions can also encourage anaerobic biological activity, which may contribute to unpleasant odors and declining lake water quality.
Managing Organic Solids with Bioaugmentation
Communities managing freshwater lakes for recreation, irrigation, drinking water resources, or aesthetic value may benefit from strategies that address accumulated organic material and nutrient cycling.
Bioaugmentation introduces selected populations of beneficial microorganisms to help support the continuous biological breakdown of organic solids.
Increasing populations of heterotrophic bacteria may help:
- Degrade accumulated organic matter
- Reduce organic bottom solids
- Support nutrient management
- Limit seasonal nutrient releases
- Improve water clarity
- Support healthier biological conditions
Using ProBiotic Scrubber® I for Freshwater Lake Treatment
The following case study describes the use of BioLynceus® ProBiotic Scrubber® I (PBI) in several 4- to 6-acre freshwater lakes.
The treatment program was designed to increase biological decomposition of accumulated organic material, support nutrient management, and improve overall freshwater lake clarity and water quality.
Figure 1. Comparison of one of three case study lakes before PBI treatment (left) and after several months of PBI applications (right).
Freshwater Lake Water Quality Challenges
A small residential community in the Colorado Rocky Mountains relied on a system of three 4- to 6-acre freshwater lakes as part of its drinking water supply.
Each summer, nutrient release from the decomposition of accumulated organic matter contributed to large algal blooms.
As algae and other organic material decomposed, dissolved oxygen levels declined and the lakes periodically developed hypoxic conditions. These low-oxygen conditions contributed to fish kills and strong, unpleasant odors.
Organic Solids Reduce Water Clarity
The lakes also developed poor water clarity as dark organic material accumulated above the sediment.
Because the community relied on these lakes for drinking water and recreation, improving water clarity, odor control, and overall lake conditions became an important management priority.
The President of the community’s Board of Directors contacted BioLynceus® for assistance.
A biological treatment plan was developed with two primary goals:
- Reduce accumulated organic solids and odors
- Improve water clarity for drinking water and recreational use
Using ProBiotic Scrubber® I for Lake Bioaugmentation
BioLynceus® ProBiotic Scrubber® I (PBI) was used to introduce live cultures of heterotrophic bacteria into the lakes.
These microorganisms were added to support the biological breakdown of organic material and improve nutrient cycling.
During the first year of treatment, PBI was applied during the summer after algal blooms had already begun forming.
By winter, algae levels had decreased and odors were reduced.
The dark organic solids at the bottom of the lakes also showed greater decomposition than had been observed in previous untreated years.
Hot, Dry Conditions Increase Algae and Fish Stress
The following spring was unusually hot and dry.
Water levels dropped significantly, while algae growth increased.
Before PBI treatment began that season, approximately 1,000 fish died in the lakes during a period of high water temperatures and low dissolved oxygen.
After the event, ProBiotic Scrubber® I was applied to the lake system to help reduce accumulated organic material and odors.
Earlier Treatment Improves Seasonal Lake Conditions
During the third year, PBI applications began in early spring rather than after algae growth had already intensified.
Starting treatment earlier helped support more gradual biological decomposition of accumulated organic matter throughout the warm season.
This approach also helped moderate seasonal nutrient release and supported microbial activity without allowing dissolved oxygen to decline to the same hypoxic levels observed previously.
Improved Water Clarity and Reduced Odors
During the third treatment year, the community observed:
- Improved water clarity
- Reduced odors
- Greater organic solids decomposition
- More stable seasonal lake conditions
- Improved overall appearance of the lake system
The President of the Board of Directors reported that the final lake in the connected system eventually resembled a clear alpine lake.
In a letter of recommendation, he wrote:
“Rick Allen and BioLynceus® have been instrumental in assisting us with the remediation of our freshwater lake system.”
Supporting Freshwater Lake Clarity with ProBiotic Scrubber® I
BioLynceus® ProBiotic Scrubber® I is designed to support freshwater lake clarity, organic solids reduction, odor control, nutrient management, and healthier biological conditions.
Reference
- Committee on Environment and Natural Resources (CENR). (2000). Integrated Assessment of Hypoxia in the Northern Gulf of Mexico. National Science and Technology Council, Washington, D.C.