When the ecological reconditioning of used water falls into step with the natural environment
Situated amid the peripheral marshes around Rochefort, in a formidable green belt of some 400 hectares, and nestled between the river Charente and the town, lies the Impoundment Station – a feature that uses a unique natural water purifying technique known as lagooning and an excellent site for observing aquatic birds.
Nature on the doorstep of town
The technique of lagooning allows the entire volume of wastewater from the town to be eco-purified in vast retention pools (35 hectares in area), by exposing it to the action of sun, wind and micro-organisms.
This eco-friendly technique encourages the growth of plankton, an essential source of food to a host of water birds (160 species are regularly observed). Consequently, thousands of Shoveller ducks, scaup pochards, coots, grebes, terns and Pygmy seagulls …are attracted by the peaceful setting and the abundance of fuel which enables them to stock up for winter or their migratory journeys.
After being processed, the water pumped back into the natural environment is of “bathing water” quality, suitable for activities associated with the Charente estuary.
Reusing silt and harnessing of energy
On arrival at the lagooning station, wastewater undergoes a physical process: screening, degreasing and grit removal. The residual mud is decanted and harvested, then goes through a biogas reactor. Here, chemical reactions ‘mineralise’ this resulting mud into compost from which methane is extracted to be used for driving a co-generator, which produces electricity.