Duckweed refers to a family of floating aquatic plants with the scientific name Lemnaceae.The  Lemnaceae    are    monocots   ( like  grasses  and  palms )   and   are   divided   into   5 genera: Lemna, Spirodela, Wolffia, Landoltia andWolffiella. Of these 5 genera Spirodela is the largest and Wolffiella is the smallest.

Duckweed normally reproduces by budding (a form of a sexual reproduction)although it is capable of sexual reproduction as well. Duckweed may be the most promising plant for the twenty-first century for the following reasons:

• Duckweed produces more protein per square meter than soybeans.
• Duckweed can be used to feed fish,shrimp, poultry and cattle.
• Duckweed can purify and concentrate nutrients from wastewater (sewage effluent).
• Duckweed provides food for wildlife, especially waterfowl.

The Lemna Technologies of St. Paul, Minnesota has patented a new form of wastewater treatment. This technology combines conventional wastewater treatment lagoons with a pond covered by duckweed. This floating mat of duckweed effectively reduces the growth of phytoplankton (algae) and submerged aquatic plants by competing for nutrients dissolved in the wastewater and creating shade, which also prevents the growth of these plants. Furthermore this duckweed can be harvested and used as food for ducks and fish. This technology has the potential for recycling nutrients and producing useful products as well. Widespread use of this and similar technologies can kill 2 birds with one stone: treat wastewater and produce high protein feed materials. This technology should be particularly useful for developing countries. My interest in this technology was sparked by the abundance of life I found growing in and among the floating layer of duckweed. I was also excited by the potential duckweed has for wastewater treatment, an urgent concern all over the world.

Microbes found in both Sunset and St. Martinville treatment ponds:

Protozoa - Paramecium, Stentor, Colpidium, and Spirostomum

Bacteria - Gram negative rods