Private Sewage Disposal System

Flashcards of Sanitary Science for the upcoming exam

Percolation Test

A test to determine water absorption rates in soil

Ground water level

Basis of location and soil porosity

Private sewage disposal system

Consists of a septic tank with effluent discharging into a subsurface disposal field, into one or more seepage pits or into a combination of subsurface disposal field & seepage pits

Maximum absorption capacity

Not more than 5.12 gal/ft2 (208.6 L/m²) of leaching area per 24 hours

Residential Occupancy

Determined by the (1) number of bedrooms or apartment units in dwelling occupancies and (2) the estimated waste/sewage design flow rate

Wastesewage Bow, up to 1500 gallons/day (5677.5 L/day)

Flow x 1.5 +septic tanks

Waste/sewage Bow, over 1500 gal/day (5677.5 L/day)

Flow x 0.75 + 1125 septic tank size

Disposal system requirement

Minimum of 14m2 of trench bottom shall be provided for each system

Inlet & outlet pipe

Extend 102 mm above & at least 305mm below the water surface

Inlet compartment of any septic tank

Not be less than 2/3 of the total capacity of the tank nor less than 500 gallons (1.9 m3)

0.9mx1.5m

Min. dimension (3ft width x 5ft length) for inlet compartment

Depth of earth cover lines

Minimum of 18 inches (457 mm)

Filter material under drain lines

12 inches (305mm)

100 feet (30.5 m)

Streams

Water supply wells

Minimum Horizontal Distance of 50 feet (15240 mm)

Gutter

Usually located along the entire perimeter of roof

Strainers or Roof drain

Drain designed to receive water collecting on the surface of a roof and to discharge it into a downspout. Designed to prevent clogging

Downspout

Located every 8 to 10 meters & at every corner of the roof (but, to avoid clogging of pipes, it is best to locate them every 4 to 6 meters)

Conductor

A pipe inside the building which conveys storm water from the roof to a storm drain, combined building sewer, or other approved point of disposal

Leader

An exterior vertical drainage pipe for conveying storm water from roof or gutter drains

Area drain Catch Basin

Also collects surface water

Independent System

Brings collected water directly to the water reservoir

Storm Drainage System

Roofs, paved areas, yards, courts and courtyards shall be drained into a separate storm sewer system or combined sewer system.

Subsoil Drains

75mm (3") minimum diameter

Shall have paved area sloped toward sumps or gratings within the property lines

Filling Stations and Motor Vehicle Washing Establishments

Primary Roof Drainage

Roof areas of building shall be drained by roof drains or gutters

Scupper openings shall not be less than 4" and have a width

Equal to the circumference of the roof drain required

Cleanouts

Shall comply with the requirements of Section 719.0

Extend not less than 4" above the surface of the roof

Dome Type Strainer or Strainer for general use

Testing

No less than 2 drains shall be installed in roof areas of 10,000 ft2 (929 m2) and additional 1 drain for every 10,000 ft2 of roof area.