Use of Bacterial Cultures to Control Oily Wastewaters
from a Bulk Oil Handling Terminal
C. A. CASWELL, Senior Associate
Gurnham & Associates, Inc.
Chicago, Illinois
The operations of this bulk oil handling terminal provide an interesting case
history of a solution to a rather complex hexane soluble removal problem. This
problem occurs because of the wide range of oil and petroleum products handled by
the facility. They not only store, and tranship, food-grade vegetable oils, animal fats
and greases but also petroleum products and petrochemicals. In addition to waste
flows generated by their own internal operations, they are sometimes called upon to
handle ballast wastewater from marine tankers and barges that deliver to the
terminal, or pick up cargo, for transhipping.
The primary sources of wastewater are the tank cleaning operations, the ballast
holding tank, the plant sanitary sewage flow, and the boiler blowdown stream. The
plant sanitary flow of approximately 2 gpm is handled by a small Smith-Loveless
"Oxigest" unit. The industrial wastewater treatment system was designed to handle
the other flows and the effluent from the "Oxigest" unit. This system consists of the
following components: 1) A collection system; 2) A.P.I, separator; 3) High-rate
oxidation pond (capacity of 150,000 gal); 4) Secondary sedimentation and
"polishing" pond (capacity of 450,000 gal); 5) A recirculation system; and 6) An
800,000 gal storage tank for ballast holding and surge flow equalization.
Flow of wastewater through the system can vary from as little as 2 gpm to as
high as 100 gpm. Influent BOD can vary from 100 mg/1 to as high as 2400 mg/1.
Influent hexane soluble components can vary from 10 mg/1 to 15,000 mg/1 plus free
floating oil or grease.
The decision to use a biologic treatment system for this problem was based
essentially on the fact that the extremely wide range of the characteristics of the
various oily products handled would have made mechanical or chemical separation
techniques either too inefficient or too costly. Since no municipal sewerage system
was available the system had to meet waterway effluent discharge requirements. This
required that contaminant contents should be equal to or less than a BOD of 20
mg/1, hexane solubles of 15 mg/1, suspended solids of 25 mg/1, be substantially
color-free, and have a pH range between 6 to 10.
Because some of the oils and greases involved in the terminal operation float,
some sink, some are "soluble" and some saponifiable, it appeared that a
broad-spectrum treatment system, if available, would be the most efficient both from
an operating standpoint and an initial cost basis. Since under normal operating
conditions   all   of   the   pollutant   components   of   the   wastewater   flow   were
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