10    CASE STUDY: EFFECTIVE WASTE MINIMIZATION
AND WASTEWATER PRETREATMENT AT
AN ALUMINUM EXTRUSION AND
ANODIZING FACILITY
Andy Miller, Project Engineer
Howard Needles Tammen & Bergendoff
Indianapolis, Indiana 46204
Ralph E. Roper, Jr., Manager, Engineering
Heritage Remediation/Engineering, Inc.
Indianapolis, Indiana 46251
Richard C. Fulk, Director of Engineering & Manufacturing
PPG Industries, Inc.
Kokomo, Indiana 46903
INTRODUCTION
PPG Industries, Inc. is a worldwide manufacturer of architectural glass, metals, paints and coating
products. Their manufacturing facility in Kokomo, Indiana designs, fabricates and ships aluminum
architectural moldings for store fronts and entrance systems. The plant has been in operation since
1967 and at present time employs approximately 150 people.
The extrusion and anodizing operations of PPG's Kokomo facility produce a wide variety of waste
streams which must be effectively managed in order to maintain compliance with local pretreatment
limits and minimize operating costs. With minor exceptions, wastewater has historically been pre-
treated via pH neutralization and discharged to Kokomo's sewer system. The pretreated discharge is
regulated by an industrial discharge permit issued to PPG by the City of Kokomo.
FACILITY OVERVIEW
Two major production processes take place at the PPG plant. The first, an extrusion process,
involves the extrusion of 2-1/2 foot-long billets of aluminum through one of two extrusion presses.
The billets are loaded into the furnace where they are heated and forced through a die to create the
desired shape of molding. Once extruded, the parts are discharged onto a conveyor and walking table
where they are cooled, via fans or spray water and/or heated in an aging oven and prepared for
anodizing. The extrusion line generates wastewater in the form of non-contact cooling water, dummy
block cooling water, caustic die cleaner and rinse water, and cooling spray water. The extrusion
process is operated approximately 50 weeks per year, five days per week, two shifts per day. Based on
a review of recent production records, it is estimated that approximately 14,000,000 pounds of
aluminum are extruded annually.
The second process is the anodizing line which involves the anodizing of extruded product through
one of two trains of batch tanks (referred to as Lines A and B). The final product can either be clear
or color anodized. A peak throughput of approximately 50,000 pounds per day can be anodized
through Line B, but current production is estimated at about half that amount.
At the time of our study, Line A consisted of 16 tanks and Line B 25 tanks. The sequence of batch
tanks is similar for both lines, although at the current time, only Line B is used. The sequencing of
batch tanks for anodizing Line B is as follows: soap tank, rinse, caustic etch, rinse, anodizing, rinse,
seal, rinse. Parts are transported from one tank to the next via an overhead crane. In connection with
batch tanks, other processes such as water conditioning, solution heating and cooling, and rectifying
are directly involved with aluminum anodizing. The anodizing line generates wastewater in the form
of rinse water, partial batch tank dumps of the soap, etch and anodizing tanks, and as dragout.
48th Purdue Industrial Waste Conference Proceedings, 1993 Lewis Publishers, Chelsea, Michigan 48118. Printed in
U.S.A.
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