MIL-HDBK-1138
2.4.2.1
Reuse Feasibility Study. An engineering study is
required to determine the actual water usage for a given reuse
project. For example, an irrigator will not need water in wet
periods or winter. The FOTW may therefore need to dispose of all
of its effluent for extended periods of time. The permit
requirements need to be flexible to accommodate such seasonal
effects. The objective of the engineering study is to determine
a conceptual reuse system, including customers, available
capacity, the size of the pipeline, pumps, and storage. This
study is not a design-level project. Further design and
permitting is required to implement a project.
2.4.2.2
Reuse Treatment Facilities. An FOTW may need
additional treatment capability to provide reuse-quality water.
If there is a possibility of public contact with the water, then
the effluent must have high-level disinfection (<20 MPN [most
probable number] per 100 mL). Filtration before disinfection or
discharge to an irrigation system would also be likely. If only
a portion of the effluent flow is used for reuse, then these
additional facilities would need to be sized accordingly and
would treat only a side-stream. An engineering feasibility study
would need to determine the size and layout of these treatment
facilities.
2.4.3
40 CFR Part 503 Sludge Regulations. Biosolids
have beneficial plant nutrients and soil-conditioning properties.
However, biosolids may also contain heavy metals, bacteria,
viruses, protozoa, parasites, and other microorganisms that can
cause disease. If improperly treated and applied, they may also
attract nuisance vectors, such as insects and rodents. The EPA
actively promotes management practices that provide for the
beneficial reuse of biosolids while maintaining or improving
environmental quality and protecting human health. However,
while the Part 503 regulations encourage the beneficial reuse of
biosolids, they do not mandate it; traditional disposal methods
such as landfilling may still be selected.
The use and disposal of biosolids, including domestic
septage, are regulated under 40 CFR Part 503. This regulation,
promulgated on February 19, 1993, was issued under the authority
of the Clean Water Act, as amended in 1977, and the 1976 Resource
Conservation and Recovery Act. For most sludges, the new
regulation replaces 40 CFR Part 257--the original regulation
governing the use and disposal of sludge that has been in effect
since 1979. Sludges generated at an industrial facility during
the treatment of domestic wastewater, commingled with industrial
wastewater in an industrial wastewater treatment facility, are
still covered under 40 CFR Part 257 if the solids are applied to
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