MIL-HDBK-1005/9A
2.5.10.2 Treatment System. Principal pollutants in graving
dock industrial wastewater are grit and suspended matter and
heavy metals. Grit should be removed at the drydock facility
using velocity control grit channel with an agitation-type grit
washer (refer to paragraph 2.5.6.2). If flow and grit loads are
small; pump discharge can be directly to grit washer. The need
for heavy metal removal must be determined by wastewater
monitoring on an individual-case basis considering local sewer
ordinance and pretreatment requirements and drydock activities.
2.6
Wastewater Treatment
2.6.1
General Design Considerations. Refer to MIL-HDBK-
1005/8 for guidance on many design considerations that are
applicable to both domestic and industrial wastewater collection
and treatment.
2.6.1.1
Effluent Limits. Follow NPDES permit requirements for
industrial wastes that are treated at a NOTW (refer to paragraph
2.5.2). For industrial wastes that discharge to a POTW, obtain
the necessary sewer use ordinance from the municipality. Sewer
use ordinances will define industrial wastewaters that must be
restricted from entering the system and define the necessary
levels of various constituents prior to entry into the system
(refer to paragraph 2.2).
2.6.1.2
Treatment Versus Pretreatment. Where possible, it is
preferable to provide pretreatment and discharge to a POTW,
rather than providing separate treatment of wastes from Navy
facilities and then discharging into a water body. Separate
treatment and discharge of industrial wastes should be
considered only if a municipal system with sufficient capability
to handle the waste is not located nearby, or if the surcharge
costs levied by the municipality plus the cost for any
pretreatment are excessive in comparison to separate collection
and treatment. Pretreatment and discharge to a municipality
versus separate treatment and discharge to a water body should
be analyzed as a part of the preliminary engineering studies
required in NAVFACINST 4862.5.
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