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3.8 CHAPTER THREE

location of soil and rock strata should then be established by test borings and excavation
of test pits. This information is vital to establish the bearing capacity of soils, to estab-
lish rock elevations, and to determine groundwater levels. Location of soil borings or test
pits should be indicated on the site topographic plan, with the site survey coordinated to
accurately locate the geotechnical investigations. Seismic conditions at the site may also
have to be investigated to determine any special design considerations that need to be ad-
dressed. In addition, it may be necessary to conduct hazardous materials investigations to
identify any potential site contamination or subsurface concerns.

Architectural Design. Development of the architectural design for water treatment plant
facilities must be closely coordinated with the process design as the treatment building
requirements are normally based on the process requirements. Architectural concepts
should be compatible with plant surroundings, with particular emphasis on minimizing
building maintenance. Architectural design is also based on input from the other design
disciplines, including
• Treatment unit and support facilities enclosure requirements
• Equipment and piping/conduit space requirements
• Operator access requirements and maintenance provisions
• Public access requirements to plant facilities
Where practical, architectural concepts used for plant additions or modifications should
be compatible with existing plant buildings. Provisions for laboratory, office, maintenance
shop, locker rooms, restrooms, storage, lunch rooms, meeting rooms, and control rooms
are usually included in the plant design.
Structural Design. Structural design is normally most affected by the civil, process, and
architectural design decisions. The size and location of the treatment structures are par-
ticularly critical to structural design. If unusual or difficult geotechnical conditions are en-
countered, it may be necessary to change structure concepts to adapt to the subsoil con-
straints. As a result, early coordination with the geotechnical investigations is necessary
to identify any unusual conditions. Water containment structures will require special pro-
visions to minimize water leakage and allow for variation of water level within the
structure.

Mechanical Design. Mechanical design establishes heating, ventilating, and air condi-
tioning (HVAC) requirements for buildings and enclosed structures. Chemical handling,
storage, and laboratory areas normally require special attention because of their unique
HVAC requirements. Mechanical and architectural designs must be coordinated closely
to ensure that sufficient building space is allocated for the plumbing and HVAC equip-
ment and ductwork. Fire protection systems may also be required for some plant areas,
particularly the chemical handling and storage areas, and will need to be coordinated with
the local fire department.

Electrical Design. Electrical design should address a number of issues related to other
design disciplines, including
• Power supply needs for all plant equipment and ancillary facilities
• Standby power requirements for treatment and support systems
• Energy conservation measures for plant operation
• Interior and exterior lighting requirements for operation and security