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Waste Water Treatment Experimental Plot
Trials for improving the water quality in Leiden
A test site has been organized at the Leiden-Zuidwest Waste Water Treatment Plant for carrying out demonstration trials. The objective of these practical tests is to remove even more substances from waste water and further improve the quality of the water. The study started in November 2006 and will go on until the end of 2008. This website provides more information on the trials, the background, the planning and the processes. As soon as the results of the research are known, they will be published on this site.
The Water Framework Directive
In its Water Management Plan 2006 the hoogheemraadschap van Rijnland (Rijnland District Water 
Control Board) has stated that it wishes to realise filtration units at various water treatment plants by the year 2015. This to ensure clean water in the future, particularly with a view to the European Water Framework Directive. The Water Framework Directive provides for the cleanest possible water throughout the whole of Europe. The standards for the water quality in Europe will be announced in 2009. Rijnland draws up its standards on the basis of the European framework.We are currently carrying out tests in order to improve waste water treatment plants so that we are well prepared in 2009. These tests will enable us to choose the right technology and introduce it in Rijnland without delays when the time comes. Click here for more information on the European Water Framework Directive.
Water treatment then, now and in the future
Then:Waste water treatment plants first came into use at the beginning of the 20th century. The waste water was stored in a special tank. Heavier particles sank to the bottom and the relatively clean water flowed over the edge and was discharged into the surface water. The smell was dreadful and the ‘treated’ water was still polluted.
Now:These days there are modern units at waste treatment plants. The waste water first goes through a coarse sieve that removes the larger particles. It is subsequently subjected to biological treatment, or treatment by bacteria, and now and then chemicals are added. In this way a lot of the pollutants are removed from the water, but the water – which already meets the strictest standards – is not as clean as it might be.
In the future:At the trial plant we are investigating new supplementary treatments to remove even more substances from waste water and further improve the quality of the water. Various methods, including sand filters, are used to purify the water still more.
STOWA
The STOWA (the Foundation for Applied Water Research) is participating in the demonstration 
project. The project is geared to STOWA’s objectives to carry out research into the improvement of water management. The STOWA follows the study through a supervisory committee. This supervisory committee is composed of professionals from other water boards who think along with us and advise where possible.
The European Union is supporting this research. We will choose the right technology for all our treatment plants on the basis of the results of the trial. Other water treatment plants in the Netherlands and Europe will also use the results to produce even cleaner water.
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More information
If you would like more information about the trials at Leiden-Zuidwest Waste Water Treatment Plant, please contact Wouter Dijksma: Wouter.Dijksma@rijnland.net.
