ULTRAFILTRATION FOR TODAY'S OILY WASTEWATERS:
A SURVEY OF CURRENT ULTRAFILTRATION SYSTEMS
James R. Wahl, Market Manager
Thomas C. Hayes, Sales Engineer
Myles H. Kleper, Engineer
Steven D. Pinto, Application Engineer
Abcor, Inc.
Wilmington, Massachusetts 01887
INTRODUCTION
Diverse industrial sources generate bdlions of gadons of ody wastewater dady. These
ody wastewaters can be grouped into three broad categories: waste containing free floating od, unstable od/water emulsions and highly stable od/water emulsions. Free oil is
readdy removed by gravity separation devices. An unstable od/water emulsion can be
mechanicady or chemicady broken, then gravity separated. However, stable emulsions
require more sophisticated treatment techniques to meet today's effluent limitations.
Ultrafiltration, in conjunction with gravity separation devices, is successfully processing
stable emulsions to produce an effluent meeting regulatory limitations and a low-volume
ody concentrate.
Tubular ultrafiltration systems are currently being operated by nearly 200 plants within
the industries shown in Table I. In an effort to confirm design data and compare operating
systems, Abcor surveyed users of tubular ultrafdtration systems in the United States. The
industries and SIC classifications of the 21 survey respondents are summarized in Table II.
A discussion of the design, operation and performance of the ultrafiltration systems surveyed is presented below.
Table I. Major Industries where Ultrafiltration Solves Oily Wastewater Problems
Industry Sources of Oily Wastes
General Metalworking Water-soluble coolants, cutting and grinding oils, and lubricants used
in machining operations.
Discharges from parts washer tanks, rinsewaters and floor washings.
Primary Metal Rolling and drawing oils used as lubricants and coolants in ferrous and
nonferrous operations.
Waste Collection Emulsified and water-soluble oily wastes collected by waste haulers from
other industries.
Food Processing Natural fats and oils from animal and plant processing, particularly
vegetable ody wastes.
Transportation Oily waste discharges from tank car cleaning operations.
Textiles Natural oils from wool scouring, fabric finishing oils.
ULTRAFILTRATION
Overview
Ultrafdtration is a low-pressure membrane process for separating emulsified oil and
suspended solids from wastewater. In an ultrafdtration system, a wastewater feed is
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