MIL-HDBK-1005/16
Section 9: EFFLUENT DISPOSAL/RECLAMATION
9.
9.1
Introduction. Two primary means of effluent disposal
and reclamation are surface water discharge and land application.
Rapidly growing technologies for disposal and reuse include
groundwater recharge and aquifer storage and recovery.
WEF MOP 8, Chapter 20, covers the applicability, pretreatment,
methodology, design, and regulatory issues involved with land
application. This handbook covers the design of surface water
discharge outfalls and discusses the emerging groundwater
recharge and aquifer storage and recovery technologies.
9.2
Surface Water Discharge Outfalls. Permit compliance
can be facilitated by the judicious selection and design of a
surface water outfall. Often the receiving water is already
dictated by the location of the FOTW or existing facilities. In
some cases, the outfall can be relocated or modified to improve
the ability of the FOTW to remain in permit compliance without
major treatment process changes. This section reviews some
general issues to consider about surface water outfalls.
Additional design references include Mixing in Inland and Coastal
Waters, Fischer et al., 1979, and Wastewater Engineering:
Treatment, Disposal, and Reuse, Metcalf & Eddy, 1991.
9.2.1
Outfall Location. A surface water discharge cannot
impair the receiving water quality below the state's water
quality standard. This is typically determined through a waste
load allocation study. This study evaluates the assimilative
capacity of the water body. Receiving waters with little
flushing, like lakes, or which are dominated by effluent, like
small creeks, are only used as a last alternative. If a larger
water body with more dilution capability is nearby, then it may
be necessary to pipe the FOTW effluent to this larger water.
Note that new open ocean outfalls in the Atlantic Ocean and Gulf
of Mexico are highly discouraged by EPA. After the general
location of the outfall in the receiving water has been
determined, then more specific design details are evaluated.
9.2.2
Outfall Configuration. The configuration of the
outfall pipe itself can sometimes be changed to improve permit
compliance. For example, if the waste load allocation determines
that the effluent is causing dissolved oxygen depletion, a
cascading structure along a stream bank can be used to satisfy
some of the effluent's oxygen demand. However, often the outfall
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