The duckweed solution

Challenge: Duckweed kills plants and fish. The weeds grow exponentially over the summer. How can we limit the growth of duckweeds and maybe even deploy the weeds for something useful?

Current situation

The Delfland Water Board (Hoogheemraadschap van Delfland) is a water quality manager. They can also control water flows somewhat with inlets and water pumping stations. Duckweed is high in protein and compostable but contains many other contaminants, such as litter and especially plastic. At the moment, Omnigroen keeps some of the ditches duckweed free by working with people who have a distance to the labor market. However, this is not a real solution.


What are we looking for?

For this project, we are looking for ways to limit and/or remove duckweed growth, and (in addition) methods to use duckweed.


What are we not looking for?

Ways to remove duckweed that harm the environment.


What is the impact?

A healthier ecological climate for the city’s ditches, in line with the current coalition agreement for ecological management and quality of outdoor space. With the right solution, ditches will never be covered with more than 40% duckweed and the surplus can be re-used in a useful way.

Almost 6% of the city consists of water including at least 300 kilometers of ditches. About a quarter of the ditches have problematic duckweed growth in July and August. By reducing the duckweed there will be more oxygen for plants and fish, less stinking water, and less visible litter.

In addition, a successful initiative can later be scaled up to other places and municipalities that face similar problems.


What can you win?

  • The opportunity to realize a prototype/pilot;
  • An extensive program with training;
  • Possible follow-up project or sustainable cooperation after a successful pilot;
  • Access to finance for the development of your prototype/pilot