Waldo, who hails from Jabbeke near Bruges, is studying in Kortrijk, the West Flemish student capital. On Tuesday night he drove his bike to meet up with friends, but no trace of him has been seen since.
Alain Remue of the Missing Persons Unit: "We've now carried out an aerial search using visual images and an infrared camera. We can't rule anything out. We also got divers from the fire brigade to search waterways in the vicinity of Kortrijk University."
No trace of the youngster was found.
Alain Remue: "This is very worrying as time is not on our side. I've learned never to give up hope, but at this moment things do not look good."
Waldo Van Raemdonck is of slender build and 1.85 m tall. At the time of his disappearance he was wearing dark jeans, a brown jumper, a brown rain coat and a scarf.