Encyclopedia of Environmental Science and Engineering, Volume I and II

SMALL FLOW WASTEWATER TREATMENT TECHNOLOGY FOR DOMESTIC AND SPECIAL APPLICATIONS 1085

FIGURE 2

Subsurface absorption system. (Adapted from Ref. 2.)

Backfill

BarrierMaterial

3/4

–2

-1/2

in. Rock

Water Table orCreviced Bedrock

PerforatedDistributionPipe

1-3 ft 6-12 in.

1-5 ft

2-4 ft. Min.

(a) Typical trench system

4 "

Inspection Pipe

Reinforced Concrete CoverExtended to Solid Earth

Effluent

Brick, Block, Ring, orPrecast Chamberwith Open Joints 6 "

to 12

" of

3/4

–2

1/2

"

Clean Rock

Influent

Water Table

4' min. Unsaturated Soil

Impervious Layer

(b) Typical seepage pit system

Straw, Hay or Fabric

Fill

Topsoil Straw, Hay or Fabric

Fill

Topsoil

Cap Cap

Distribution Lateral

Distribution Lateral

Absorption Bed

Absorption Bed

Plowed Layer of Top SoilSlope

Rock Strata or Impermeable Soil Layer

(c) Typical mound for a slowly permeable soil

on sloping site

3

1

Plowed Layer of Top Soil

Permeable Soil

Water Table or Creviced Bedrock(d) Typical mound system for a permeable soil with high groundwater or shellow creviced bedrock

3

1

C019_002_r03.indd 1085C019_002_r03.indd 1085 11/18/2005 11:06:46 AM11/18/2005 11:06:46 AM