Sewage treatment system

Claim 1

A sludge concentrator system for solid material in a liquid carrier, comprising: a. drum means rotatable about a horizontal axis b. endless filter media screen means having a length substantially greater than the circumference of said drum means, c. said screen means being trained around said drum means and idle roller means horizontally displaced from said drum means so that a generally horizontal upper reach of said screen means is defined therebetween, wherein said upper reach of said screen means is inclined slightly upwardly in the direction of said drum means, d. baffle means bracketing said upper reach adjacent said idle roller means so as to contain said liquid laden sludge on said upper reach. e. means for feeding liquid laden sludge onto said upper reach adjacent said idle roller means, f. said drum means being rotatable in a direction to draw the screen means from said idle roller means toward said drum means, g. whereby gravity de-watering of the sludge through the upper reacH of the screen means takes place as the screen means moves toward said drum, and h. said drum having vacuum means therein for drawing additional water from the partially de-watered sludge as it passes over said drum wherein said vacuum means includes valve means associated with said drum for causing a vacuum to be effective on the surface of the drum only in a fixed arcuate segment of the drum''s rotational cycle and wherein said fixed arcuate segment includes a greater arc span of said drum than the first quadrant of said drum, measuring from the top of the drum in the direction of its rotation but less than the first and second quadrants together.