SSF-800For skimming of slow sand filters Skimming of slow sand filters without emptying has long been a request from the water market. Weda is now launching a remote controlled robot that can run on the sand bed and remove the so called schmutzdecke and pump it to the desired landfill. The machine sucks in 1 3 cm of schmutzdecke and the sand that is pumped out of the slow filter. The method also works on facilities with infiltration ponds. The estimated