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EPA 625/1-80-012
DESIGN MANUAL
ONSITE WASTEWATER TREATMENT
AND DISPOSAL SYSTEMS
U.S. ENVIRONMENTAL PROTECTION AGENCY
O f f
i i c e o f Water Program Operations
Office o f Research and Development
Municipal Envi ronmental Research Laboratory
October 1980
NOTICE
The mention o f trade names or commercial products i n t h i s publication i s
for
i l l u s t r a t i o n purposes and does not constitute endorsement or
recommendation for use by
the U. S.
Environmental Protection Agency.
ii
FOREWORD
Rural and suburban communities are confronted w i t h problems t h a t are
unique t o t h e i r size and population density, and are often unable t o
superimpose solutions typically applicable t o larger urban areas.
A
good example of such problems i s the provision of wastewater services.
I n the past, p r i o r i t i e s f o r water p o l l u t i o n control
focused on the
c i t i e s , since waste generation from these areas was most evident.
I n
such hi gh- densi ty development,
the tradi tional
sanitary engi neeri ng
approach was t o construct a network of sewers t o convey wastewater t o a
central l o c a t i o n f o r treatment and disposal t o surface waters.
Since a
large number o f users existed per u n i t length of sewer line, the costs
o f construction and operation could be divided among many people,
thus
keepi ng the financial burden on each user relatively low.
Within the past several decades, migration o f the population from c i t i e s
t o suburban and rural areas has been significant. With t h i s s h i f t came
the problems
o f
providing
u t i l i t y
services
t o
the
residents.
Unfortunately, in many cases, solutions to wastewater problems in urban
areas have been applied t o rural communities.
With the advent of
federal programs t h a t provi de grants f o r construction of wastewater
faci l ities,
sewers and centrali zed treatment plants were constructed
in
these low-density rural s