Practical Duckweed:
Application Areas and Sponsors
Bioremediation
Aquaculture & Mixed -Use
Animal Feed Supplement
Environmental Testing & Research
Automated environmental test
Pharmaceuticals
Patents and Inventions
US Government Research
Companies Putting Duckweed to Work
Bioremediation

Fueling the rapid growth of duckweeds requires substantial amounts of nutrients.  Thus duckweeds have evolved the ability to rapidly remove minerals necessary for their growth from the water on which they float.  When present, duckweeds also can remove many organic nutrients.  These mineral and organic nutrients are converted into the substance of the plants, that is, their biomass.  Research has shown that duckweeds are especially adept at removal of phosphates and nitrogen, particularly ammonia.

The treatment of sewage and wastewater from agricultural operations requires the removal of great amounts of nitrogen and phosphate.  These wastes are a growing problem around the world because of population growth and the trend of modern farming operations to concentrate livestock in small areas.

The duckweed biomass that results from water treatment operations must itself be removed from the water.  This can be done by skimming it off.  Duckweed grown on sewage or animal wastes normally does not contain toxic pollutants and can be fed to fish or to livestock, or spread on farmland as a fertilizer.  If the duckweed is to be fed to animals, a retention period in clean water will be necessary to ensure that the biomass is free of water-borne pathogens.

The links on this page illustrate both potential and proven duckweed applications.

Above:  Video, Duckweed as a Renewable and Sustainable Biofuel Feedstock by Philomena Chu, Rutgers University.
Below left:  swine in North Carolina Below right:  a duckweed treatment lagoon inside a plastic greenhouse. 
swine in North
              Carolina Duckweed
              treatment lagoon inside a plastic greenhouse.
Photos courtesy of Paul Skillikorn.
Smith, Ryan Andrew. Harvesting Duckweed By Skimming, M.S. Thesis, North Carolina State University, Biological and Agricultural Engineering, Raleigh, NC, 2003, 153 pp. [ link to download site ]
  1. Landesman L, Parker N C, Fedler C B and Konikoff M (2005) Modeling duckweed growth in wastewater treatment systems. Livestock Research for Rural Development. Vol. 17, Art. #61. Retrieved October 30, 2005.
  2. Nutritional value of wastewater grown duckweed for fish and shrimp feed.
  3. Effects of Herbivory and Competition on Growth of Lemnaceae in Systems for Wastewater Treatment and Livestock Feed Production(A).
  4. Effects of Herbivory and Competition on Growth of Lemnaceae in Systems for Wastewater Treatment and Livestock Feed Production (B).


Aquaculture

"The Mirzapur Shobuj Shona project, inaugurated in 1989 was the first flow-through wastewater treatment system in the world to cover capital and O&M costs while also making a healthy profit on operation of the system itself."

Duckweed Aquaculture, Paul Skillicorn, William Spira & William Journey. A New Aquatic Farming System for Developing Countries. (1993) The World Bank, 76 pp.  Available from The World Bank Group, World Development Sources in printed copy.
Shobuj Shona Evaluation,  Bangladesh, (1993) Enterprise, Asset Accumulation and Income Generation in Bangladesh: A New Model for Women in Development, Rebecca Torres, University of California, Davis  (428k)

Mixed-Use




 

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Revised:  February 22, 2014