Removal of Oil and Solids From
Rolling Mill Wastes
Ernest Fuller,  Research and Development Engineer
Great   Lakes   Steel   Corporation
Detroit, Michigan
Great Lakes Steel Corporation, a Division of National Steel Corporation, is located on the Detroit River several miles south of Detroit.
The Detroit River connects Lake St. Clair with Lake Erie and serves
as the boundary between the U. S. and Canada. In the vicinity of the
plant, the river is approximately three-quarters (j^) of a mile wide and
has an average depth of about 30 ft.
The construction of the plant was begun in 1929 on a site that
covered approximately 275 acres. Over the years adjacent properties
have been secured, construction has continued, and at the present time
the plant covers 572 acres. The plant now employs approximately 10,000
people, and it has an annual capacity of 3,500,000 tons of ingots.
The first operating units included open hearth furnaces and hot
rolling mills. All mills were provided with scale pits in their sewer
systems to collect mill scale, grease, and oil. A scale pit is a concrete
basin that is equipped with a baffle, with an inlet at one end and an
outlet at the other. The baffle retains the oil in the basin; scale and
grease collect in the bottom of the pit and are removed by means of a
clamshell bucket. This is standard construction for steel mill sewers
flowing from hot mill installations. However, stream pollution authorities do not consider that these basins provide adequate protection against
pollution.
The cold rolling units at our plant were installed in 1937 and 1938.
Elaborate oil collecting systems are located in the cellars under the
mills. All water and oil coming from the mills are passed through
collecting tanks. Twelve thousand to 15,000 gallons of oil are collected
each month and processed for reuse. This system was (and still is)
considered to be one of the most successful in the industry. Because the
rolling on these mills is done cold, there is no mill scale to contend with.
However, due to the space limitations, the size of these tanks is insufficient to provide complete protection against loss of oils to the sewers.
After World War II, increased attention was directed toward
preventing pollution of the nation's lakes and rivers. The major sources
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