There is disclosed a solids collection and removal system for a settling tank. It is particularly designed for installation in generally rectangular, in-ground settling tanks such as is commonly used for water treatment. The collection device includes a plurality of bottom-travelling collectors which have elongated, open-bottomed channel housings, each with a scraper blade pivotally supported by a pin-in-slot attachment to provide a modified pendulum suspension. The collectors, which span the width of the tank, are mounted on a track or other suitable mechanical linkage for oscillatory travel across preselected portions of the bottom of the settling tank. Each collector is divided by a longitudinal baffle into a lowermost collection chamber and an upper evacuation chamber. The latter is connected through a conduit to a vacuum system for the evacuation of the solids from the collectors.