Environmental Engineering FOURTH EDITION

Wastewater Treatment 201

Figure 9-22. An aerial view of a secondary wastewater treatment plant. (Courtesy of
Envirex.)

Figure 9-23. An unusual operating problem: a pickup truck in the primary clarifier.
(Courtesy of Phillip Karr.)

is complex and demanding (though not often as demanding as the situation shown
in Fig. 9-23). Unfortunately, operators have historically been poorly compensated,
so that recruitment of qualified operators is difficult. All states now require licensing of
operators, and operators’ pay is improving. This is a welcome change, for it makes little