Can nitrate filters help mitigate nitrate pressure in surface water?

03 May 2023 - Published by Charlotte Boeckaert
Even when farmers fertilize according to plant needs, this does not guarantee that nitrate pressure in surface water remains below EU targets. Inagro (Belgium) tested filter systems on pilot plots and can confirm that these filters are a part of the solution. Dominique Huits from Inagro shares her considerations and insights.

From nitrate to nitrogen gas

When you put nitrate (in water) in contact with a carbon source, the conversion of nitrate to nitrogen gas occurs, the so-called denitrification. In fact, this is a process that is also used in conventional wastewater treatment. It is a well-known way to remove nitrates from water. Simple, right? Whereas in a conventional wastewater treatment plant all parameters can be controlled (flow rate, water quality fairly stable, operator present, ...) this is completely different for drainage water:

-        The amount of drainage water is highly dependent on the amount of rainfall

-        Nitrate concentrations are unpredictable


In addition, there are also some additional challenges

-        Filters must be robust without an operator having to look after it

-        The water temperature can be quite low. This is an additional challenge for the conversion of nitrate to nitrogen gas

-        The filter must be affordable

-        Tile-drains occur in remote locations with limited or no access to electricity

At Inagro, we are testing three nutrient removal filters for their robustness to remove nitrate from drainage water. Read more about the field test results.