Page 96 - Water and wastewater engineering

GENERAL WATER SUPPLY DESIGN CONSIDERATIONS 2-39

Likewise, because residuals are generally transported off-site, the residuals handling system is an
integral part of the plant layout.

2-6 PLANT LOCATION
Ideally a site comparison study will be performed after alternatives have been screened and rough
sizing of the processes is complete. Many factors may preclude the ideal situation. For example,
in highly urbanized areas the availability of land may preclude all but one site. In some cases the
availability of land may force the selection of processes that fit into the available space.
Given that more than one site is available, there are several major issues to be considered. As
noted in Chapter 1, cost is a major element in the selection process. In addition, the site should
allow for expansion. The location of the plant relative to the transportation net, raw water supply,
and the service area should be weighed carefully. The physical characteristics of the site alterna-
tives that must be evaluated include the potential for flooding, foundation stability, groundwater
intrusion, and the difficulty in preparing the site. For example, the need for blasting of rock
may make the cost prohibitive for an otherwise ideal site. Other issues to be considered include
wetland infringement, the availability of alternate, independent sources of power, waste disposal
options, public acceptance, and security.

Visit the text website at www.mhprofessional.com/wwe for supplementary materials
and a gallery of additional photos.

2-7 CHAPTER REVIEW
When you have completed studying this chapter, you should be able to do the following without
the aid of your textbook or notes:

1. Explain to a client the influence of regulatory constraints on the selection of a design
period.
2. For a given population growth rate, select an appropriate design period.

3. Explain to a news media person the influence of local factors such as climate, industrial
development, and meterage on a national estimate of unit demand.
4. Explain to a client why groundwater is often preferred as a source of water.

5. Use a yield curve to estimate a safe yield.
6. Describe the potential deleterious effects of overpumping a confined or an unconfined
aquifer.
7. Explain the implications of a flat or steep slope in a log-probability plot of a water
quality parameter in the design of a water treatment plant.
With the use of this text, you should be able to do the following:

8. Construct a yield curve.
9. Construct an annual minima series.