MIL-HDBK-1138
evolve, treatment system design criteria must be reviewed to
confirm continued suitability.
Mission conversions can necessitate modifying
stormwater/wastewater drainage systems. Stormwater from areas
that are uncontaminated under one mission may be contaminated
under another mission, and vice versa. Oil/water separators that
do not have a stormwater diversion system can suffer from reduced
removals from the hydraulic loading of stormwater that does not
need to be treated. Thus, separator collection systems also must
be reviewed for excessive stormwater flows.
Contaminants in Wastewater Stream. Particulate heavy
5.3.6
metals and solids in the wastewater will settle into the sludge
at the bottom of the oil/water separator receiving compartments.
The sludge could be regulated as a hazardous waste if levels
exceed RCRA or state hazardous waste levels. Solvents or fuels
may also be retained in oil/water separator sludge.
5.4
Evaluation of Need for Oil/Water Separators.
Unauthorized discharges of industrial pollutants, as well as
inadequate O&M of oil/water separators, can create serious
liability and noncompliance. If an oil/water separator is not
needed to meet pretreatment or discharge permit limits, or to
allow for beneficial reuse, it should probably be removed to
eliminate the management responsibility and the potential
liability associated with it (Figure 6). Although this is an
environmental issue, operators can assist by knowing what is
discharged to separators, educating others whose activities are
generating the wastewater, and alerting their environmental staff
of any problems. Because of the potential and significant effect
on oil/water separator O&M, it is especially important to ensure
that only wastewater associated with vehicle and equipment
maintenance activities are discharged to oil/water separators.
This wastewater typically contains oil and grease but has a
relatively small amount of solids. (By comparison, exterior
washing of vehicles and equipment, particularly after field
training exercises, can discharge large quantities of solids.
Consequently, at many installations, central vehicle wash racks
are specifically provided for exterior washing and this is not
permitted at maintenance facilities.) Oil/water separator users
should assist environmental staff with the tasks detailed below.
In addition, operators can assist environmental
management staff in evaluating the need for and effectiveness of
existing oil/water separators with the goal of consolidating or
eliminating ineffective units. Issues to consider in evaluating
the need for oil/water separators are discussed below.
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