MIL-HDBK-1138
normal propagation, growth and survival of the indigenous
aquatic biota.
To address this narrative criteria, most states apply a
whole-effluent toxicity requirement in the permit. The whole-
effluent approach to toxics control for the protection of aquatic
life involves the use of acute and/or chronic toxicity tests to
measure the toxicity of wastewaters. The acute test assesses the
lethality of the wastewater to the test organisms and is
typically conducted for 96 hours or less. The chronic test
assesses growth and reproduction in addition to lethality and is
typically conducted over a 7-day period. Whole-effluent toxicity
tests use standardized surrogate freshwater or marine plants,
invertebrates, and vertebrates. The test is run at the same
dilution as is allowed for the wastewater in the receiving
stream. Failure to meet the criteria results in the need to
conduct a toxicity reduction evaluation on the discharge.
2.4.1.5
Negotiation of Effluent Limits. Careful review by
the discharger of the specific basis used for the water quality-
based effluent limits is advisable. In many cases, the basis
used in the development of the effluent limits is open to
negotiation. These issues should be addressed during the permit
renewal process.
2.4.2
Wastewater Reuse. Several states and communities
are promoting the reuse of wastewater as a beneficial way of
reducing both drinking water demands and wastewater discharge to
the environment. The most common reuse projects involve large
uses of water for irrigation purposes (e.g., golf courses).
Other uses of water may include residential irrigation, fire
protection, landscape features (ponds or fountains), and
industrial supply. Generally, a project is only considered a
reuse project if the reclaimed effluent replaces drinking water
demand.
Groundwater discharge is sometimes referred to as
"groundwater recharge" and may be considered reuse if it is used
to replenish the drinking water supply. However, contamination
of the drinking water supply is a concern, and the discharge may
have as many disincentives as incentives. Most land application
projects that rely on groundwater infiltration for effluent
disposal would be considered disposal projects, not reuse
projects. Any disposal to natural surface waters will be
considered an NPDES discharge and will be subject to all
applicable rules.
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