Filtration at moderate rates on upward-facing horizontal surfaces is accomp
anied by sedimentation. Kynch theorems developed for sedimentation in the n
oncompression range can be adapted to explaine the evolution of the cake su
rface and the filtrate volume with time. The different relationships obtain
ed have been tested with filtration + sedimentation runs and filtration wit
hout sedimentation runs carried out with calcium carbonate suspensions at m
oderate pressure differences from 17 to 97 mmHg. The differences between th
e average specific resistance observed at the different runs can be satisfa
ctorily explained by the fundamentals of the theory.