12 May 2003
Including change 1, 19 January 2007
. Ship sewage settles well and
treatment, but it may be septic. Table 3-4, "Typical Ship Sewage Concentrations",
define typical concentration values. Wastes from shipboard industrial activities are not
included. High dissolved solids, chloride, sulfates, and sodium concentrations apply
when seawater flushing or ballast systems are used. For more information on ship
sewage, refer to NAVSEA S9086-AB-ROM-010, Naval Ship's Technical Manual
Effect of Wastewaters with High Seawater Content.
Performance. High concentrations of seawater tend to inhibit biological
treatment. Process inhibition is related to the chloride concentration of the
For new designs: Currently, there is an absence of pilot plant data
or treatment data from similar wastewaters. Consequently,
compensate for high seawater content according to the data
presented in Table 3-4.
In analyzing the capacity of existing treatment facilities to receive
ship's wastewater, use figures defined in Table 3-5. If these
indicate overloading solely because of chloride inhibition, conduct
pilot plant tests before planning any expansion. Consult with the
Activity and the cognizant NAVFAC EFD/EFA OR USACE
DISTRICT for instructions.
Sudden changes in chloride concentration may upset biological
processes. Consider equalization storage to limit chloride variation
at the wastewater facility. For chloride concentrations in excess of
5000 mg/L, provide design limitations of 200 mg/L/h.
Maintenance. High seawater content in wastewater will aggravate
incrustation problems. Avoid fine bubble air diffusion systems and design
orifices to facilitate periodic cleaning of mineral deposits. This is
especially applicable to orifices in trickling filter flow distributors or in
aeration devices. Use care in selecting construction and equipment