WASTEWATER TREATMENT PROCESS — CLICK ANY STEP TO EXPLORE
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STEP 1Bar Screens, Fine Screens, Grit Chamber
Screening & Grit Removal
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Interactive Diagram
Click the labelled buttons on the diagram to learn about each component
🧪 WATER QUALITY AT THIS STAGE
BOD
200–300 mg/L
TSS
200–350 mg/L
Odour
Strong H₂S
Appearance
Dark grey/brown
WHAT HAPPENS HERE
Raw wastewater (sewage) enters the plant through the headworks. Coarse bar screens remove large solids — rags, wipes, plastics — that would damage downstream equipment. Fine screens follow, then grit chambers slow the flow so sand, gravel, and coffee grounds settle out by gravity.
⚡ KEY EXAM POINTS
1
Bar screens: openings 6–150 mm; protect pumps and pipes
2
Fine screens: 1–6 mm; remove smaller fibrous material
3
Grit chambers sized for 2–5 min detention time at peak flow
4
Grit removal prevents abrasion of pumps and accumulation in clarifiers
📋 ONTARIO REGULATION
O. Reg. 129/04 requires headworks screening to protect downstream equipment. Screenings and grit must be disposed of in accordance with the Environmental Protection Act.