TREATMENT OF OILY WASTES BY ULTRAFILTRATION/
REVERSE OSMOSIS
A CASE HISTORY
Marshall K. Sonksen, Senior Mechanical Engineer
Aluminum Company of America
Davenport, Iowa   52808
F. Mark Sittig, Staff Environmental Engineer
Edward F. Maziarz, Section Head - Industrial Wastes
Aluminum Company of America
Pittsburgh, Pennsylvania   15219
INTRODUCTION
Alcoa is the world's leading producer of aluminum. Founded in Pittsburgh, PA in
1888, it now has more than 45,000 employees situated throughout 52 operating locations and 114 sales offices around the globe. Alcoa's principal operations include mining
bauxite, alumina and chemical production, smelting and fabricating aluminum into
semifabricated and finished products. Alcoa also is a major participant in urban real
estate and land development projects and has diversified into a variety of businesses
related to its basic facilities and technology.
Alcoa's principal fabricating process is rolling, in which aluminum ingot is progressively reduced in thickness by repeatedly passing it between pairs of rolls. The Company's
Davenport Works is one of the world's largest aluminum sheet, plate and foil rolling
mills. The facility, more than one mile in length, is situated on a 445-acre site alongside the Mississippi River with over 100 acres under roof. Since the start of operation
in 1948, the Works has had an almost continuous expansion program. A 220 in.
reversing mill-the world's largest of its type-was completed in 1971. Production and
shipments from Davenport Works average over one million lb   of aluminum daily. Some
examples of the end uses for Davenport products include the Saturn V rockets, space
capsules and lunar modules which were composed primarily of Alcoa aluminum. The
plate, used for many of the liquid natural gas tankers, is rolled on the 220 in. mill.
There is virtually no domestically made commercial airliner flying today that does not
include Davenport Works aluminum in its wings and fuselage.
During the rolling process, an oil-in-water emulsion is used as a coolant for the rolls
and metal, as a lubricant to decrease horsepower losses due to friction, and as a cleaning solution to carry debris away from the sheet. While these emulsions are filtered and
recirculated, fresh batches of soluble oil are periodically required. The contaminated
rolling solutions are discharged to the process waste sewer system and, together with
mill leakages, are the main load on the Davenport Works oily waste treatment facility.
The original treatment plant, constructed in 1949, was a conventional alum and lime,
two-stage chemical de-emulsification system with a lagoon and incineration for sludge
disposal. Although it has undergone several renovations and additions since then, the
chemical system did not produce an effluent that consistently met anticipated NPDES
696