Wastewater Engineering Lecturer:
Tower 1/ Aras
Ext. Sewage Treatment DA/RH
Learning Outcome At the end of Week 5 students should be able to - describe preliminary treatment - apply knowledge related to preliminary treatment
Screening, Pumping Station, Grit and Grease Removal
Remove larger particles, which can
interfere with subsequent equipment or processes.
Screening devices can be broadly classified as coarse or fine.
Smaller sized openings generate more screenings and more contaminants on screenings.
Need to handle, store, dispose of screenings. Often have screenings of decreasing openings.
Need to work at low and high flows.
Bar spacing, materials of construction and dimensions.
Channel depth, width and approach velocity. Headloss through the screens (hL = 1(V2-v2/2g) C Discharge height to accommodate screenings conveying equipment.
Angle of screen. Materials of construction and coatings for overall unit.
Screen cover to block wind and improve aesthetics and reduce odor.
Drive unit service factor.
Drive motor size and enclosure (for example; totally enclose fan cooled)
Spare parts. Provision of redundant screen or bypass screen.