Duckweed
Identification
- Small light green, floating plant
- Can occasionally have visible roots
- Has waxy surface
- Typically measures between .5cm – 1cm
Why Do I Have It?
- Found in polishing lagoons with low surface water movement and low flow
- High inorganic nutrients in water column
Associated Lagoon (Pond) Conditions
Duckweed can cause drains and pipes to clog in some systems as well as increase sludge volume. It may depend on the permit, but in some cases, excessive duckweed can cause high effluent TSS. Duckweed can form a thick mat that prevents light penetration which could result in increased E. coli. While some operators might like it for the way it reduces light penetration and algae, in some cases it can cause problems.
Treatment
Duckweed can be controlled by applications of Duckweed Complete followed about two weeks later by spraying PondZilla Pro to degrade the dead duckweed. However, chemical treatment is not always recommended as a small skimmer can block duckweed from exiting the lagoon. This floating plant is a symptom of high levels of sludge buildup and internal nutrient recycling. Sludge can be physically removed by dredging or a non-disruptive option: Sludge Rx. This can aid in sludge reduction and prevent resuspension of nutrients such as nitrogen and phosphorus.
If you’re concerned about excessive growths in your lagoon or pond, we recommend taking a few photos and sending them to your rep or info@teamaquafix.com. Our lab will look over the photos and advise on further steps.
Under the Microscope and in Your Plant
Duckweed is a small, light green, floating plant with occasionally visible roots. Duckweed is not a type of algae, but can be mistaken as such. This plant is often found in polishing lagoons with low surface water movement and low flow. Common duckweed has a very waxy surface or cuticle, that combined with the curve of its 1-3 leaves allows any liquid with the surface tension of water to roll off. This floating plant reproduces rapidly and is commonly found growing in dense colonies. These colonies can also offer a habitat for watermeal to grow. Duckweed can also cause drains and pipes to clog in some systems as well as increase sludge volume. However, duckweed can be beneficial as it reduces soluble inorganic nutrient levels and shades out the growth of other aquatic weeds and algae.