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MASTER PLANNING AND TREATMENT PROCESS SELECTION 2.3

1. Drinking water regulations, including those that are current, pending, and anticipated
2. Treatment and residuals management options and limitations that produce quality con-
sistent with regulations
3. Choices available where more than one treatment method or treatment train may be
equal in cost and other features

Treatment method development should be evaluated in the above order. Rules and reg-
ulations establish what must be accomplished in treated water quality, and often more
than one method of treatment may accomplish the required result.
The potential options and the limitations of each method are developed in the next
step. Limitations may include factors such as cost, operating control, and size of facili-
ties. Where several viable options are available, different treatment trains are evaluated,
taking advantage of the multiple choices to determine the most advantageous option. Com-
parisons here may include factors such as best fit on the site, appearance, ease of opera-
tions and maintenance, and vulnerability to upset.
On June 12, 2002, the federal Public Health Security and Bioterrorism Preparedness
and Response Act was signed. In accordance with the terms of this act, all water treat-
ment plant designs now have to be evaluated in regard to vulnerability to terrorist attack
and resulting potential damage to facilities and upset in treatment process. Incorporating
the results of these evaluations, existing emergency response plans must be revised ac-
cordingly or new plans developed. Reducing facility vulnerability and improving emer-
gency response capability must be considered in the future in both the development of
master plans and the selection of a treatment process train.
When alternative source waters are available, the potential sources (surface water and
groundwater) and specific intake or well locations should be evaluated to determine the
water quality characteristics of each source. The vulnerability of source water to future
contamination or water quality deterioration should receive particular consideration. The
variability of the source water quality should be investigated because extreme water qual-
ity conditions often dictate treatment requirements. Once a new water supply is chosen,
a protection program should be implemented (either watershed or groundwater protection)
to maintain the integrity of the supply.

Planning Periods for the Master Plan
Major capital projects, such as large water treatment plants, generally require many years'
lead time to develop meaningful design, construction, and financial arrangement plans.
This, together with the expected long life of certain facilities, results in exceptionally long
design periods for water systems. Master planning studies often develop the water sup-
ply and treatment needs for 30 to 50 years or more into the future.
Based on complexity, expendability, and cost, the various components of the water fil-
tration plant are sized to meet the needs of varying periods of time. More difficult and
expensive facilities, such as intake tunnels and major structures, are often designed for
the life of the facility, which can be as great as 50 years or more. Other facilities, such
as process treatment units, are often initially planned with a first-phase design of 10 to
25 years, with a plan to allow for future increments of expansion to accommodate the full
life of the project.
Equipment such as pumps and chemical feed systems may have an expected life of 10
to 15 years. Therefore they are designed for shorter-term capacities with allowances for
replacement to meet future needs of the facility.