There are disclosed herein equipment and methods for screening and concentrating waste water overflow from combined sewer systems. Exemplary equipment includes a separator employing a substantially cylindrical rotating screen. Influent is piped upwardly into the equipment and deflected outwardly toward the inner surface of the screen in a manner to achieve a desired flow rate and flow pattern of the influent onto the screen. Means are provided for controlling the flow rate and for suitably directing the influent in a plurality of substantially discrete inclined streams toward the inner surface of the rotating screen. The screen is rotated at a speed to achieve a desired centrifugal force. Effluent passes through the screen to an outlet and the remaining concentrate passes to an outlet. A certain amount of the influent splashes from the inner surface to the screen, and is received by a backsplash pan and may be recirculated and rescreened. The screen is in the form of a screen cage having a plurality of removable screen panels for facilitating replacement of damaged screens or changing of screen type or mesh size. Cleaning means is provided for directing a cleaning fluid periodically at the screen. The methods disclosed involve the manner in which the influent, effluent, concentrate and backsplash are handled, and the manner in which the influent is screened to achieve a fluid concentrate which is pumpable to other treatment equipment for ultimate disposal. Additionally, a sequence of influent food and screen cleaning is described.
A device is disclosed herein for distributing solids-containing liquids from a central inlet to a rotating screen cage used as a centrifugal separator. The device includes a first distributor for directing the influent radially outward against the rotating screen cage. A second distributor is located below the first distributor and is caused to rotate with the screen cage. This second distributor is designed to receive influent which has rebounded from the rotating screen cage and return that rebounded influent to a lower portion of the screen cage by centrifugal action. Vertical plates radially disposed about a distributor body and a horizontal circular plate located beneath the vertical plates act to receive and return rebounded influent. Notches are provided in the vertical plates to prevent return of rebounded influent to solid portions of the screen cage.
