CLEANING SYSTEM FOR SAND FILTRATION LAYER

To reduce the size, scale of construction, and running cost of an apparatus for cleaning a sand filtration layer. A cleaning system which removes clogging sediments from a sand filtration layer 2, used with an apparatus for an infiltration intake of seawater which performs a seawater intake, by means of a water intake pipe 4 buried in the supporting gravel layer 3, after the seawater has been infiltrated through the sand filtration layer 2 and a supporting gravel layer 3 on an ocean floor. This cleaning system is provided with a diffuser pipe 7 having blow holes 6, and which is buried in the supporting gravel layer 3, as well as a compressed air delivery device 8 for feeding an air into the diffuser pipe 7. The system operates by blowing the air from the blow holes 6 to agitate the filtration sand of the sand filtration layer 2, to remove the sediments which have become trapped in or accumulated on the sand filtration layer 2. The system can achieve a smaller size, a smaller scale of construction, and a lower running cost than a conventional system which injects fresh water or seawater into the sand filtration layer.