Unit 3: Nutrient Pollution - Sewage Treatment
- Created by: rosieevie
- Created on: 08-04-15 16:27
View mindmap
- Sewage Treatment
- Pre-Treatment (solid objects)
- Screens trap floating suspended items
- Incinerated to kill pathogens and reduce volume then put in landfill
- Grit traps collect stones/road grit at the bottom of the water
- Comminutors chop up faecal solids - increase surface area
- Incinerated to kill pathogens and reduce volume then put in landfill
- Grit traps collect stones/road grit at the bottom of the water
- Comminutors chop up faecal solids - increase surface area
- Primary Treatment (organic solids)
- Effluent allowed to stand and settle - faecal solids sink and are removed
- Sludge Disposal (pathogens and foul smells)
- Digested by anaerobic bacteria for 4 weeks
- Remaining solids settle
- Produces methane and CO2 - fuel
- Remaining sludge disposed of in landfill (cheap), sea (banned), incinerated (expensive), fertiliser (difficult to apply)
- Secondary Treatment (organic matter and bacteria)
- Aerobic bacteria and large volumes of air mixed in to make process occur at constant rate
- Bacteria allowed to settle and collected as activated sludge
- Effluent usually discharged here
- Tertiary Treatment (for sensitive or important areas)
- Phosphates removed with iron sulfate
- Bacteria removed using micro-strainers or chlorine
- Tertiary Treatment (for sensitive or important areas)
- Screens trap floating suspended items
- Pre-Treatment (solid objects)
Comments
No comments have yet been made