GB489452A - Method of and apparatus for collecting and conveying sludge in connection with sewage plant - Google Patents

Abstract

489,452. Gravity-separation apparatus. MILLS & CO. (ENGINEERS), Ltd., J., and BOLTON, J. F. April 2, 1937, No. 9369. [Class 111] In apparatus for collecting sludge for reintroducing into aeration tanks in connection with sewage plant using the activated-sludge system, the sludge deposited on the floor of a settling tank is gathered by scoops or scrapers carried by a rotatable bridge and is removed by siphon pipes associated with the scrapers, the sludge being then passed into a trough from which it is drawn off by a siphon and delivered into a well provided with an outlet for returning the sludge to the aeration tanks or elsewhere. As shown, a settling tank A has an outer and an inner circular wall provided with rails a, a<2> to support'the wheels of a rotatable bridge B. The bridge is adapted to rotate about a shaft b<3> mounted in a central sludge well A<8> which is positioned within the inner circular wall A<4>. Liquid from the aeration tank passes through an inlet pipe A<6> and through an annular grille A<7> on the wall A<4> into the settling tank. The bridge B supports a number of pivotallymounted siphon pipes c each of which is secured to a V-shaped scoop or scraper d. Each pipe can be raised, for examination, by a winch. With each pipe c is a bent portion Cx dipping into a vessel e adapted to communicate with a trough f. The inner end of the trough leads to a well f<1> into which one limb of a main siphon pipe g dips. The other limb dips into an annular trough connected by outlets h<2> to the central sludge well A<8>. An outlet pipe A9 from the well A<8> leads to a chamber A <10> having a valve-controlled outlet leading to a pump for conveying away the sludge. Priming connections and valves are provided for putting the apparatus into condition for raising the sludge from the settling tank.