CLEANING OF PONDS (LAGOONS, REEDS…)
Wastewater treatment ponds, phyto-purification systems with reeds are equipment that produce sludge in a “punctual” manner. Periodically, (every 5 to 15 years), the sludge must be extracted before saturation. This operation requires experience, equipment and skill.
■ Wastewater treatment pond with geomembrane :
The sludge is extracted in liquid form by a submerged pump supported by a raft. The operation of the lagooning system is not altered during the construction process.
■ Wastewater treatment pond in other cases :
The supply to a lagoon is cut off by a by-pass which passes the effluent and the supernatant to
another lagoon to allow the sludge to dry out. The pasty or solid sludge is extracted by a mechanical shovel equipped with a cleaning bucket. A tracked vehicle enters the basin to push the sludge towards the extraction point.
■ Filters planted with reeds and drying beds planted with reeds : The feeding of a pond is suspended while the sludge contained in it thickens. Shortly before dewatering, the reeds are mowed and drained. The sludge is extracted using a mechanical shovel equipped with a dredging bucket.