OILY WASTEWATER TREATMENT AND THE IMPACT
OF HIGH WATER CONTENT SYNTHETIC FLUIDS
AT FORD MOTOR COMPANY
Philip R. Lawrence, Engineer,
External Environmental Section
Plant Engineering Office
Ford Motor Company
Detroit, Michigan 48243
BACKGROUND
Waste oil is a significant pollutant in manufacturing operations. At some locations, such as at
machining or stamping plants, it may be the only serious pollutant. Ford has 13 machining plants and
7 stamping plants in the U.S. and Canada. Wastewater treatment flow rates at machining plants are in
the 0.5 to 0.75 MGD range. Stamping plant flow rates are usually in the 0.01 to 0.02 MGD range.
"Synthetic" fluids are man made, high water content substitutes for petroleum-oil based fluids
used for machining and/or hydraulic applications. Since 1979, Ford has conducted material performance evaluations (shop trials) on a wide variety of these high water content fluids (HWCF). Initially,
they were manufacturing oriented with very little attention given to wastewater treatment considerations.
Based on an experience with some synthetic type fluids at a Ford of Europe location, the Plant
Engineering Office of Ford Manufacturing Staff became concerned that such new fluids would inhibit
oil wastewater treatment processes.
Jar tests on wastewater that contained some of the HWCF were performed and these tests revealed
the following negative impacts on existing oily wastewater treatment systems:
1. increased cost for treatment chemicals,
2. extended time required for treatment,
3. decreased efficiency when some HWCF are present,
4. high water soluble organic levels in the treated effluent measured as chemical oxygen demand (COD) and biochemical oxygen demand (BOD).
OILY WASTEWATER TREATMENT
To help better understand these findings, the four common treatment processes that Ford has
available to treat oily wastewater are reviewed below:
1. Gravity Separation,
2. Flocculation/Precipitation,
3. Ford Windsor Process,
4. Modified Windsor Process.
Gravity Separation for Removal of Free Oil
Gravity systems typically employ API separators, in-sump oil skimmers, or wastewater batch
storage tanks. Typical manufacturing facilities using gravity separation of free oil waste have been
stamping plants and a few assembly plant systems. At these locations, free-floating oil is skimmed
from the surface to a secondary holding tank and sold to a reclaim service. The underflow is permitted
to drain to the sanitary sewer.
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