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1.4 CHAPTER ONE

Major design decisions today are no longer made unilaterally by the project team. In-
stead, a consensus is reached after participation by members of the design team and by
individuals outside the team, including owners, operators, regulatory agencies, and the
general public.

Project Delivery
The traditional procedure for construction of a new water treatment plant was for the en-
gineering design and specifications to be prepared by an engineering finn or the owner's
in-house staff. Bids were then taken, and the contract was awarded to the lowest respon-
sible bidder. The design team usually monitored the construction to see that the design
intent was carried out, and after construction was completed, the facilities were operated
by the owner.
Today, a number of changes and variations to this traditional approach are being con-
sidered or implemented. Two of the principal alternatives are

• Design-build approaches, in which one entity is responsible for both design and
construction
• Privatization approaches, in which the facility is owned by a private entity providing
treatment service for the water utility
In addition, a global marketplace for water treatment engineering has developed. Ideas
and practices are being exchanged among countries all over the world. In North Amer-
ica, there is increasing consideration of European treatment practices, technologies, and
firms.

DEVELOPMENT OF WATER TREATMENT
DESIGN PROJECTS

A water treatment design project passes through many steps between the time when the
need for a project is identified and the time that the completed project is placed into ser-
vice. The period before construction commences can generally be divided into the fol-
lowing phases:
1. Master planning. Treatment needs and feasible options for attaining those needs are
established in a report. In subsequent phases, this report may be periodically updated
to adjust to both system and regulatory changes.
2. Process train selection. Viable treatment options are subjected to bench, pilot, and
full-scale treatment investigations. This testing program provides background data suf-
ficient in detail to enable decisions on selecting the more advantageous options for po-
tential implementation. These tests provide design criteria for major plant process units.
3. Preliminary design. In this "fine-tuning" procedure, feasible alternatives for princi-
pal features of design, such as location, treatment process arrangement, type of equip-
ment, and type and size of building enclosures, are evaluated. In this phase, prelimi-
nary designs are prepared in sufficient detail to permit development of meaningful
project cost estimates. These estimates help in evaluating and selecting options to be
incorporated into the final design and allow the owner to prepare the required project
financial planning.