On-Site Wastewater Treatment and Disposal Systems - Forced ...

7.3.3.7 Seasonal, Multifamily, and Commercial Applications
Use of evaporation and evaporation/infiltration lagoons for summer homes
would result in somewhat reduced area requirements per gallon of waste-
water handled, since storage would not need to be provided during the
winter months. Otherwise, application of these systems to seasonal
dwellings is comparable to year-round residences.
Evaporation and evaporation/infiltration lagoons are also applicable to
multifamily and commercial applications, although additional ,pretreat-
ment may be required depending on the wastewater characteristics.
7.4 Outfall to Surface Waters
Direct discharge of onsite treatment system effluent is a disposal op-
tion if an appropriate receiving water is available and if the regula-
tory agencies permit such a discharge. The level of treatment required
varies, depending on local regulations, stream water quality require-
ments, and other site-specific conditions. In general, onsite treatment
system effluent disposed by surface discharge must at least meet secon-
dary treatment standards for publicly owned treatment works. Depending
on site-specific conditions, more stringent BOD and SS discharge re-
quirements and/or limitations on N and P discharges may be applicable.
The performance, operation, and maintenance requirements, and the en-
vironmental acceptability of the surface discharge depend predominantly
on the preceding treatment system. Operation and maintenance associated
specifically with the surface discharge pipe are minimal in a gravity
situation. If the effluent must be pumped, then routine pump mainte-
nance will be required.
Discharge pipes should be made of corrosion- and crush-resistant materi-
als such as cast iron or rigid plastic pipe. For single-family systems,
the pipe should range from 2 to 4 in. (5 to 10 cm) in diameter, should
be buried, and should be moderately sloped (between 0.5 and 3%). Steep
slopes may cause washout at the discharge point.
7.5 References
1. Bendixen, T. W,, M. Berk, J. P. Sheehy, and S. R. Weibel. Studies
on Household Sewage Disposal Systems, Part II. NTIS Report No. PB
216 128, Environmental Health Center, Cincinnati, Ohio, 1950. 96
PP*
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