Page 151 - Facility Piping Systems Handbook for Industrial, Commercial, and Healthcare Facilities

SOLID-LIQUID SEPARATION AND INTERCEPTORS

SOLID-LIQUID SEPARATION AND INTERCEPTORS 3.19

7. If the filter is intended to be an initial filter in the system, the beta rating should be
obtained from the manufacturer to determine its removal efficiency and performance
characteristics. Ratings for a minimum of five or more particle sizes should be pro-
vided. If the filter is used in an intermediate location, the particle sizes will be reduced
and the nominal rating of specific particulate sizes will allow for efficient selection.
8. The maximum temperature that the filter media can withstand will determine if they
can be used for service where they must be sterilized and if the media are acceptable
for sterilization using high-temperature water.
9. The maximum differential pressure is the difference in pressure between the inlet and
outlet water pressure beyond which the filter will fail structurally, and is established
by the manufacturer.
10. Effective filtration area is the measure of the usable area of the filter media indepen-
dent of the material or type.
11. The toxicity and pyrogenicity of the filter materials must be compatible with the
intended use of the product water.
12. Compatibility with any chemicals intended to be used for sterilization that will come
in contact with the filter must be considered.
13. Extractables from the filter media must be reduced to acceptable limits to prevent
problems with any downstream process. The method used most often to control and
reduce extractables is to preflush the filters prior to use.

INTERCEPTORS

GENERAL

An interceptor is broadly defined as a device that separates and/or retains a specific sub-
stance from a liquid effluent stream without impairing the ability of the remaining effluent
to be discharged into a drainage system. It is generally used where the effluent is intended
to be discharged into a public sewer system, although it is not limited to that use. The inter-
ceptors discussed here are intended to be used inside a building.
There are a number of substances that have the potential to create safety, health, or
mechanical problems within a piping network if they are allowed to be discharged directly
into a drainage system. For other substances, such as precious metals, recovery is desir-
able for economic reasons. It is therefore necessary for them to be intercepted, retained,
and (possibly) neutralized before this occurs. This is accomplished by interceptors that are
designed to protect against specific hazards.

CODE CONSIDERATIONS

Plumbing codes usually have a requirement that any liquid waste containing grease, flam-
mable materials, sand, or any other substance that, in the opinion of the local authorities, is
harmful to the building drainage system, the public sewer system, or the sewage treatment
process be prevented from being discharged. If there is any question as to the need for a
separator, the local authorities should be consulted. Approval of specific separators may also
be required.

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