Home - Vision- The specific aims of ONEMA


  • The issues involved in reusing wastewater

      Given the decrease in water resources, reuse of wastewater following treatment may be a suitable solution to meet part of the growing needs of populations and industry. Even though it is very common around the world, particularly in the countries where water resources are the most limited, reuse of wastewater is very rare in France. Water reserves in France are considerable, but consumption is also very high. Reuse of treated wastewater could be a means to reduce draw-offs and to preserve the quality of aquatic environments by limiting the release of effluents from treatment plants. The water could be used in particular for irrigation of crops and watering of parks and recreational installations in cities.

ONEMA and the "Grenelle de l'environnement" commitments

Prevention of chemical pollution | Management of water resources | The blue corridor

2) Management of water resources

Commitment 111 I Detect water leaks in water networks and schedule the necessary work

     An observatory on the performance of public water and water-treatment services in France will be created. In France today, there are almost 30.000 public water and water-treatment services under the direct responsibility of the towns. They operate under very different conditions in terms of the local geography, economy and water quality. Their management systems are also highly diverse. Onema is currently setting up a national observatory to evaluate the performance of these services and report to the public and elected officials. It is the result of wide-ranging discussions with all stakeholders in the water field. The observatory will go on-line at the end of 2009 and will provide information notably on water leaks in networks.

Maintenance and rehabilitation of water networks

Important topics for study include the improvement of our knowledge on the physical phenomena leading to leaks, the compared profitability of different leak detection and reduction techniques, and the creation of performance indicators. Onema has requested from Cemagref an evaluation of the physical installations in French distribution networks and of the economic consequences of strategies for their preventive maintenance and rehabilitation.

Commitment 118 I Develop new systems to recover and reuse rainwater and wastewater

Use of rainwater in cities and homes

     The International office for water (IOWater) prepared for Onema a summary on current technologies used worldwide and case studies on the management of rainwater in cities.

Four approaches with different goals for rainwater management stood out, namely
1) management of water and pollutant flows,
2) landscape improvement of urban areas,
3) the resource itself,
4) temperature regulation in collective housing and in the city itself.

A panorama of current regulations and aids in the Netherlands and Germany concerning the use of rainwater in homes was drawn up in a second study conferred by Onema to IOWater. Following an evaluation of the action taken, the study proposes guidelines taking into account the experience acquired by these two countries that have innovated in the use of rainwater. In the Netherlands, the ministry ran a study on six test projects using water for washing in homes.

Reuse of treated wastewater

The reuse of treated wastewater raises the issue of health risks and the treatment required to eliminate any pollutants and contaminants. A study funded by Onema and run by Cemagref revealed the components representing the greatest risks for human health and the environment, namely micro-organisms, organic (detergents, pesticides, solvents) and inorganic (trace metals) micropollutants, and dissolved salts. Thanks to this study, the treatment techniques capable of reducing or even eliminating risks for human health and the environment were identified. For example, disinfection techniques are often the means to avoid risks due to micro-organisms and membrane technologies are effective against dissolved and/or residual pollutions. In France, waste-stabilisation ponds, landfills using membranes and activated sludge installations coupled with disinfection, filtering and waste-stabilisation ponds would appear to be the technologies best suited to the required level of quality.

Onema also commissioned a study on experiments reusing wastewater in Mediterranean countries, a part of the world where water resources are particularly limited and where reuse of wastewater is the most common.

Commitment 179 I National solidarity with overseas territories

Onema solidarity programme

     In 2008, Onema set up its solidarity programme, representing 14 M€ for overseas territories. More than 12 M€ will contribute to ten wastewater-treatment plants and the corresponding networks in Réunion, French Guiana, Martinique, Mayotte and New Caledonia. And approximately 2 M€ will be devoted to specific studies dealing with the consequences for aquatic environments of water contamination by chlordecone in Martinique and Guadeloupe, and by gold washing in French Guiana. These studies are being carried out in a partnership, notably with the Water agencies.