Bar screen, hand cleaned type. (A) wastewater stream,
(B) screen chamber, (C) bar screen, and (D) drainage platform.
(2) Screen cleaning. Screenings should be raked off the screen and onto a
drainage platform. As soon as most of the water has drained, screenings should be
placed in a receptacle (such as a trashcan) and covered to await disposal. The screen
chamber and screen should be flushed frequently to remove grease and accumulated
solids from walls and bars. Fine screens require scrubbing or brushing. Greasy tools
may be cleaned with kerosene.
(3) Disposal of screenings. Screenings contain putrescible material and
must be disposed of daily in a sanitary manner. At small installations, screenings are
commonly buried. Use of the sanitary fill is appropriate for this purpose. At large
installations, they may be incinerated with sludge gas from the secondary treatment
processes being utilized as fuel. An alternative is to grind the screenings and pass
them into primary sedimentation units where they settle and are later digested with