Collection Systems for Community Wastewater Systems

Collection Systems for Community Wastewater Systems

CAWPCA Spring MeetingApril 26, 2013Dave Prickett, PE

OVERVIEW• Wastewater Management• Community Systems Plans• Collection Systems Alternatives• System Selection Considerations• Examples

Wastewater Management Alternatives

Community Systems (> 25 homes)

Work Backwards from Here

Collection System Alternatives

Why Is Sewer Selection Important?

Gravity & STEG Sewers

Gravity STEG

Treatment Peak flows from I/I

Peak flows from I/I;May minimize treatment requirements

Disposal/Reuse Potential salinity in coastal areas

Potential salinity in coastal areas

ConstructionDepth and dewatering concerns; conflicts with other utilities

Depth and dewatering concerns; conflicts with other utilities

Private Property Minimal post-construction access needs

Septage management required

O&M Facilitates access for routine maintenance

Slightly lower mainline pipe O&M needs than conventional gravity

Emergency Readiness

Self sufficient during outages if pump stations have generators

Self sufficient during outages if pump stations have generators

Low Pressure, Vacuum & STEP Sewers

Low Pressure Vacuum STEP

Treatment

Lowest I/I & high flow potential; pre-treatment

Relatively low I/I potential

Condition of existing septic tanks impacts I/I

Disposal/Reuse Minimal salinity

impactsSlightly higher salinity impacts

May minimize treatment requirements

Construction Shallow construction minimizes duration

Moderate construction impacts; need to site vacuum station

Shallow construction minimizes duration

Private Property

Significant access needs

Moderate access needs

Significant access needs

O&MOdor control needs Odor control needs

Odor control needs; septage management

Emergency Readiness

Significant concerns during power outages

Moderate concerns during power outages

Significant concerns during power outages

Example

Example (continued)

QUESTIONS & ANSWERS