Wastewater Collection Systems Flashcards
sewage
(or wastewater) the liquid containing contaminants that is generated by toilets, showers, sins and industrial processes
sewerage
the whole system of sewers and pump stations which convey sewage to a treatment plant
sewer
the pipeline which conveys sewage, normally by gravity flow
pressure main
(or rising main) a pipeline conveying pumped flow
STP
Sewage Treatment Plant
- where sewage is treated to the standard required for discharge to land or receiving waters
Effluent
normally refers to the partially or fully treated sewage from septic tanks or a STP
Influent
normally refers to the sewage entering a STP or partially treated sewage entering subsequent treatment process
Types of Wastewater Collection Systems
- Conventional Gravity Sewerage (CGS)
- Common Effluent Disposal (CED)
- Variable Grade Sewers (VSG)
- Septic Tank Effluent Pumping (STEP)
- Grinder Pumps (GP) (and pressure mains)
- Vacuum System (VS)
CGS
Conventional Gravity System
Advantages of Conventional Gravity System
- low operations and maintenance cost
- no equipment at house
- all sewage removed from site
Disadvantages of Conventional Gravity System
- higher capital cost
- greater disruption during construction
CED
Common Effluent Disposal
Advantages of Common Effluent Disposal
- smaller pipes, flatter grades
- reduced organic load at WWTP
- reduced peaking factors
Disadvantages of Common Effluent Disposal
- septic tanks must be maintained
- requires septage facility
VSG
Variable Grade Sewer
Advantages of Variable Grade Sewers
- smaller, shallower pipes
- reduced organic load at WWTP
- reduced peaking factors
Disadvantages of Variable Grade Sewers
- may need higher maintenance
- pump and check valves required at low properties
- septic tanks must be maintained
- requires septage facility
STEP
Septic Tank Effluent Pumping
Advantages of Septic Tank Effluent Pumping
- smaller, shallower pipes
- reduced organic load at WWTP
- reduced peaking factors
- reduced infiltration
Disadvantages of Septic Tank Effluent Pumping
- septic tanks must be maintained
- require septage facility
- large number of pumps to run and maintain
- potential odour and corrosion issues
GP
Grinder Pumps
Advantages of Grinder Pumps
- smaller, shallower pipes
- reduced infiltration
- all sewage removed from site
Disadvantages of Grinder Pumps
- large number of pumps to run and maintain
- septic effluent
- potential odour and corrosion issues
VS
Vacuum System
Advantages of Vacuum System
- smaller, shallower pipes
- reduced infiltration
- all sewage removed from site
Disadvantages of Vacuum System
- unfamiliar technology
- vacuum pump discharge odour
- potential odour problem due to seasonal loading
