Initiated by the Vientiane municipality, this project to treat sewage sludge with filters planted with reeds was launched in 2015. It is coordinated by the International Association of Francophone Mayors (AIMF) which has been requested by the Vientiane municipality, and which coordinates the project and co-finances it with other financial partners (Seine Normandy Water Agency, SIAAP). The AIMF and the Vientiane municipality have recruited a prime contractor, the WTA (Water Technical Assistance) for the design, construction and commissioning of the treatment plant, as well as the GRET, which is working on the organizational framework and the awareness and communication strategy, which are also essential for the proper functioning of the service.
From a technical point of view, eight beds for drying sewage sludge have been set up, planted with reed plants that act as filters, aerate and reduce humidity. After cleaning the beds, the sludge is stored. Once dry, they can be used for soil fertilization (humus) in agriculture. The idea is to reproduce, and intensify, the mechanism at work in natural rose gardens. The Vientiane plant is capable of treating 36,000 m3 of sludge per year, corresponding to Vientiane's wastewater production, within 15 years.
Finally, household awareness and a good communication strategy are essential for households to understand the importance of treatment for urban hygiene and to properly drain their wastewater.