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THE CHALLENGE OF WATER TREATMENT PLANT DESIGN 1.3

ity of the source water entering the plant and devise treatment facilities to produce water
meeting drinking water standards. The point of measurement for drinking water standards
was the finished water exiting the plant.
Today's engineer must view the water treatment plant as only a major component in
a multistep treatment process. This process includes consideration of the path that the wa-
ter travels upstream of the plant in the watershed and the elements of the water trans-
mission and distribution system downstream of the plant. Changing water quality must
be managed in each of these steps, and new regulations require that drinking water stan-
dards be met at the customer's tap.

Regulatory Uncertainties
The definition of "safe" drinking water, which remained relatively fixed in the 1950s,
1960s, and 1970s, now seems to be constantly changing or under review as the water util-
ity industry grapples to understand the potential health effects of trace amounts of an in-
creasing variety of chemical compounds and infectious organisms. Today's treatment sys-
tem engineer, in addition to addressing current drinking water standards, must anticipate
potential future requirements. A water system designed today must be designed with suf-
ficient flexibility to be modified to meet these potential requirements.
Regulatory uncertainties extend to other environmental concerns important to water
treatment plant design, including waste management practices, chemical storage and feed
operations, and workplace safety.

New Technologies
The state of the art of water treatment plant design is continually changing as new tech-
nologies emerge, offering new unit processes for water treatment or making currently used
processes more efficient or economical. In addition, advances in computer technology and
building materials are rapidly changing and improving the support systems associated with
water treatment plants.

Multidiscipline Teams

A water treatment plant engineering design team traditionally consisted simply of a small
group of civil engineers. This single-discipline team performed the majority of design
work for virtually all plant components. Support disciplines of architects and structural,
electrical, and mechanical engineers were used to execute the basic decisions made by the
design team.
Today, the complexity of project and regulatory requirements dictates that a far more
multidisciplined approach be used. Typically, a small group of civil engineers remains as
the "project" engineers, but this group uses the expertise and resources of many different
specialists to execute the design. In addition to traditional design support disciplines, these
may include
• Process engineers
• Plant operations specialists
• Instrumentation and control engineers
• Health and safety specialists
• Environmental scientists
• Specialists in environmental permitting and public participation