Page 31 - Water and Wastewater Engineering Design Principles and Practice

1-2 WATER AND WASTEWATER ENGINEERING

1-1 INTRODUCTION

Overview
Water and wastewater engineering encompasses the planning, design, construction, and supervi-
sion of water and wastewater systems. This chapter gives an overview of the design and construc-
tion process as an introduction to planning. Chapters 2 through 17 address water treatment. The
subject matter follows the flow of water (and the design of unit processes) from the development
of a source through the unit processes of coagulation, flocculation, softening, reverse osmosis,
nanofiltration, sedimentation, granular filtration, membrane filtration, disinfection, and residuals
management. The topics of wastewater treatment follow a similar pattern of following the flow
through a plant. Chapters 18 through 28 address preliminary treatment, primary treatment, sec-
ondary treatment, tertiary treatment, and residuals management. Special attention is given to the
application of membranes.

Setting the Stage
Before presenting the design and construction processes, the stage is set by identifying the
project participants and their roles. The Code of Ethics provides a framework to discuss the
professional–client relationship. Responsible care is introduced as a higher level of perfor-
mance than demanded by the code of ethics.

1-2 PROJECT PARTICIPANTS
Decision making for any municipal water or wastewater engineering design involves many par-
ticipants: the public, the regulator, the legal counsel, the owner, the designer, the financier/invest-
ment banker, the operator, and the contractor. The owner serves as the focus of all the project’s
activities. The design professional, as a member of the design team under the owner’s direction,
responds to the project’s design needs. The design team consists of principal design engineers
and supporting specialists (WEF, 1991).

All projects begin with an identification of a problem by the regulator, the public, legal counsel, or owner.
The design professional then enters the project during the idea generation and evaluation phase of the
problem-solving activity. Thereafter, the design professional or firm generally participates actively in all
of the project’s activities, typically until the end of the first year of operation. (WEF, 1991)
The design professional may enter the process by many routes. Typically one of the fol-
lowing three methods or a combination of the methods are used to obtain engineering design
services:

• Request for Qualifications (RFQ): The owner solicits qualifications from firms that wish to
be considered for engineering services on a design project.

• Request for Proposals (RFP): The owner solicits proposals for engineering services on a
project. The RFP usually includes a requirement to provide a statement of qualifications.
Alternatively, the RFQ may be a second step following the evaluation of the responses to
the RFP.
• Qualified Bidder Selection (QBS): The owner selects the design firm from a list of previ-
ously qualified companies.