Apparatus and method for separation of solids from liquid

摘要

Method and apparatus are provided for separating coarse and ultrafine solids from a liquid stream to produce a substantially dry solids discharge and a clarified liquid. Apparatus is provided comprising a combination of a settling tank, a plurality of filter screens spaced along an endless link-chain conveyor, a screen vibrator and directed air streams. In operation, coarse solids settle preferentially to the tank bottom. Ultrafines solids remain in suspension. Relatively coarse filter screens are conveyed from a point outside the tank to traverse a prolonged path through the liquid. Ultrafine solids are captured on the screens, by filtering the liquid through an ever finer build-up of filter cake. The relatively large number of passes of the screens through the liquid provides effective filtering of suspended solids. Further, the screens dredge settled solids from the tank bottom. After exiting the liquid, collected coarse and ultrafine solids are dewatered by vibration of the screens and directed blasts of air. Dewatered solids are dumped external to the tank and clarified water is recovered from the tank. Enhanced polymer flocculation may be practised to form flocs from ultrafine solids, after which flocs may be collected (filtered/dredged), dewatered and dumped using the invention. Dewatered solids can further be subjected to compression and decompression cycles to separate even more water from the solids.