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

7.3.3 Evaporation and Evaporation/Infiltration Lagoons
7.3.3.1 Description
Lagoons have found widespread application for treatment of municipal
wastewater from small communities, and have occasionally been used for
wastewater treatment in onsite systems prior to discharge to surface
waters. A more common application in onsite systems has been for treat-
ment and subsequent disposal by evaporation, or a combination of evapo-
ration and infiltration.
A discussion of evaporation and evaporation/infiltration lagoons is pro-
vided, since thousands are currently in use across the United States.
However, performance data are very limited. The information provided in
this section is based on current practice without assurance that such
practice is optimal.
7.3.3.2 Application
In the United States, an evaporation or evaporation/infiltration lagoon
could be used in most locations that have enough available land. How-
ever, local authorities typically prefer or require the use of subsur-
face disposal systems where conditions permit. Thus, actual application
of these lagoons is generally limited to rural areas where subsurface
disposal is not possible. In addition, use of evaporation/infiltration
lagoons is not appropriate in areas where wastewater percolation might
contaminate groundwater supplies, such as in areas of shallow or crev-
iced bedrock, or high water tables. Use of both types of lagoons, espe-
cially evaporation lagoons, is favored by the large net evaporation po-
tentials found in arid regions.
Data on the impact of influent wastewater characteristics on evaporation
and evaporation/infiltration lagoons are very limited. Pretreatment is
desirable, especially if a garbage grinder discharges to the system.
7.3.3.3 Factors Affecting Performance
The major climatic factors affecting performance of evaporation and
evaporation/infiltration lagoons include sunlight, wind circulation,
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