American Water Works Association, American Society of Civil Engineers, Design of water treatment plants is evolving. New technologies and unit processes continue
to emerge and have become much more common since the publication of the third edition
of the Water Treatment Plant Design 7 years ago. Security issues, summarized in a new
chapter in this fourth edition, have forever redirected many aspects of design. Additional
reference materials for security design considerations are becoming available and should
be consulted for further information.