Encyclopedia of Environmental Science and Engineering, Volume I and II

348 ENVIRONMENTAL HEALTH

bottom mud and sludge worms become very numerous. In

the zone of recovery the process is gradually reversed and

the stream returns to normal. The zones mentioned may not

be discernible or experienced where sewage has been given

adequate treatment before discharge.

Small Waterborne Sewage Disposal Systems

The provision of running water in a dwelling or structure imme-

diately introduces the requirement for sanitary removal of the

used water. Where public sewage works are available, connec-

tion to the sewer will solve a major sanitation problem. Where

public or central sewage works are not provided or anticipated,

such as in predominately rural areas, then consideration must

be given to the proposed method of collection, removal, treat-

ment, and disposal of sewage on each lot as shown in Figure 9.

With a suitable soil, the disposal of sewage can be simple, eco-

nomical, and inoffensive; but careful maintenance is essential

for continued satisfactory operation. Where rock or ground

water is close to the surface or the soil is a tight clay, it would

be well to investigate some other property.

The common system for sewage treatment and disposal at

a private home in a rural area consists of a proper septic tank

for the settling and treatment of the sewage, and a subsurface

leaching system for the disposal of the septic tank overfl ow,

provided the soil is satisfactory. The soil percolation test and

soil characteristics are used as means for determining soil per-

meability or the capacity of a soil to absorb settled sewage. This

and the quantity of sewage from a dwelling are the bases upon

Check

Pump

Cable

to pump

Well casing

Bleeder

orifice

Pitless adapteror sanitary well Check

seal and gasket

Below frost

Cement

grout

Alternate pit

adjacent to foundation

Discharge

pipe

Slope floor

to celtar

3 ' min. from roof

overhang

Cable Sanitaryseal

Sampling

tap

Gate

valveCap

Pressure

tank

Pressure

switch

Air control and

pressure gauge

Electric

box

Final grade^12 "

12 "

Alternate well

cap and cable

hook up.

Details of a submersible pump connection

FIGURE 6 Sanitary well caps and seals. Reprinted with permis-

sion, from Environmental Sanitation, Joseph A. Salvato, Jr., John

Wiley & Sons, Inc., copyright, 1958.

ZONE OFAERATION

ZONE OF

SATURATION

LAND SURFACE

SOIL WATER

SUSPENDED WATER

CAPILLARY WATER

GROUND WATER WATER TABLE

IN FALL

AVERAGE

WATER TABLE

WELL CASING

CEMENT GROUT

ANNULAR SPACE

AVERAGE STATIC

WATER LEVEL

AVERAGE

PUMPING

LEVEL

DRILL HOLE

EARTH OVERBURDEN

TILL, CLAY, GRAVEL, SAND,

SILT, HAROPAN, OTHER

INTERNAL WATER

WATER BEARING ROCK CREVICESAND

FRACTURES

FIGURE 7 A geologic section showing ground water terms. From Rural Water Supply, New York State

Department of Health, Albany, NY, 1966.

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