High-value crops can be irrigated with recycled water, thus saving valuable potable drinking water. Photo: Janne Hansen

Important knowledge about water and soil from the Faculty of Agricultural Sciences, Aarhus University, is being put to work in southern Europe and other areas with insufficient potable drinking water.

2009.04.22

Clean water to drink is in short supply in many places around the world. Global climate change is making a bad situation even worse. With intelligent water recycling for crop irrigation, life-saving drops of the precious liquid can be saved. Scientists from the Faculty of Agricultural Sciences, Aarhus University, are contributing knowledge and solutions to the problem in the EU project SAFIR.

Up to 80 percent of water consumption in southern European countries such as Spain, Italy and Greece is spent on irrigating agricultural crops. Demand placed on the all-important potable water is increasing as potable water becomes in short supply in these areas. What to do? Should the crops thirst? Or should people thirst?

Neither crops nor people need to go without water if the water resources available are used sensibly. In the comprehensive EU project SAFIR scientists from several countries are investigating how this most valuable resource can be used optimally.

Soils rinse water

One of the methods is to recycle grey water and use it to irrigate high-value agricultural crops – typically vegetables. Scientists from the Faculty of Agricultural Sciences are on the bandwagon in this regard with their knowledge of how soil rinses water for bacteria and other pathogens. This knowledge is being used in another work package of SAFIR, in which the company Grundfos Biobooster A/S is helping to develop advanced, compact biological-mechanical technology for local treatment of municipal wastewater.

Recycled (grey) water typically contains pathogens, including bacteria. When the water percolates through the soil, some of the pathogens are held back. How clean the water becomes after its journey through the soil depends on how many pathogens the grey water contains and on soil type, managements and inherent soil properties.

Scientists from the Faculty of Agricultural Sciences at Aarhus University and from the University of Copenhagen have quantified these processes. They have poured water infected with various concentrations of pathogens, including E. coli bacteria, on different soil types in a so-called semi-field facility. This is a facility in which you can roll the ”sky” back and forth and thus prevent uncontrolled natural precipitation on the plants and soil. The facility also enables scientists to study subsoil conditions, such as plant root development, without having to dig in the soil.

Healthy food with recycled water

The results from the studies indicate how contaminated the water may be, before it is applied to various soil types under various conditions. This knowledge is used by Grundfos Biobooster A/S in their development of a water treatment facility to evaluate how thoroughly the water needs to be treated before being used under given conditions.

The aim is to recycle water from towns in local communities for use in crops grown close to the towns – which would typically be the case for vegetables that can be sold at a relatively high price.

Besides investigating what happens to the water in different soil types, the Faculty of Agricultural Sciences participates in other parts of the project and acts as a liaison for the collaboration between international scientific institutes and other partners and also helps in the testing of the various versions of the new water treatment plant in China, Serbia, Crete and Italy.

For more information please contact: Senior scientist Finn Plauborg, Department of Agroecology and Environment, Faculty of Agricultural Sciences, Aarhus University, telephone: +45 8999 1809, mobile: +45 2218 1809, e-mail: Finn.Plauborg@agrsci.dk

Facts about SAFIR:

- A total of 7.1 million EUR, including 4.7 million EUR from the EU, has been granted to the project.

- Participating in the project are 17 partners from 10 different countries, including EU countries, China and Israel.

- The Faculty of Agricultural Sciences is the coordinator of the project.

- SAFIR is the acronym of the project and stands for “Safe and High Quality Food Production using Low Quality Waters and Improved Irrigation Systems and Management”

- You can read more about the SAFIR project at www.safir4eu.org.

Text: Janne Hansen