81    ELECTROPLATING/METAL FINISHING WASTEWATER
TREATMENT: PRACTICAL DESIGN GUIDELINES
Richard D. Johannes, Chief
Gregory J. Humpal, Project Engineer
Wayne V. Schmidt, Project Engineer
Industrial Wastewater Engineering
Burns and McDonnell Engineering Co.
Kansas City, Missouri 64141
Robert O. Hoffland, President
Atlantes Chemical Systems, Inc.
Conroe, Texas 77303
INTRODUCTION
In the consulting engineering arena, the constant pressure to perform the design function at a cost
less than the competition often prevents the designer from conducting research prior to being driven
to arrive at a conclusion. As such, we are constantly faced with the decision on what is "good
enough". The experience accumulated by the authors in the area of electroplating and metal finishing
wastewater treatment has been acquired from a combination of hands-on experience, review of
literature, mistakes (ours and others), equipment vendors, and peers within and outside our own
respective firms.
In the process of developing this chapter, it quickly became apparent that it would be impractical to
attempt to cover the broad boundaries of the subject as originally envisioned. Thus, the coverage
selected is limited to the destruction of cyanide complexes and the reduction of chromium from the
hexavalent state to the trivalent state, i.e., the pretreatment processes to a pretreatment facility.
Considering that the coverage of this chapter is the destruction of cyanide complexes and the
reduction of chromium, the following represents the purpose of this chapter: 1) identify and outline
the procedures the designer may apply in the orderly production of the process flow sheet or the
Piping and Instrument Diagram (P&ID); and 2) develop and present a "CHECKLIST" for use in the
achievement of the design effort, particularly as it applies to selecting the treatment processes to be
used.
In the following paragraphs, the procedure described is pertinent to both the cyanide destruction
and chromium reduction process selection as well as applicable to any treatment process selection.
The procedure is discussed here to avoid repetition.
THE FIRST ROUND OF QUESTIONING
The development of the design criteria at the outset represents a commonsense approach. Table I
provides a listing of the basic elements the Design Criteria should include.
The first and foremost question which must be answered prior to commencement of design is
whether the quantity of wastewater to be treated is the minimum. In addition to influencing the
selection of the processes, this question impacts the cost of implementing the system. Table II lists
recognized processes or procedures for waste reduction which should be considered prior to commencement of design. A thorough discussion of these processes or procedures is beyond the scope of
this chapter.
The rationale for "Recovery vs Treatment" entails three principal factors which control their
application. These factors are: 1) straight economics; 2) elimination or reduction of treatment capacity; and 3) elimination or reduction of sludge generation.
Having assured oneself that the quantity of wastewater discharged from shop operation is at a
minimum, without adversely impacting either the quality of the product or the cost of the operation,
43rd Purdue Industrial Waste Conference Proceedings, © 1989 Lewis Publishers, Inc., Chelsea, Michigan 48118.
Printed in U.S.A.
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