8    HAZARDOUS SLUDGE REPROCESSING AND REDUCTION
IN PETROLEUM REFINING
Carole L. Engelder, Waste Minimization Coordinator
Amoco Oil Company
Texas City, Texas 77592
Mary K. Spearman, Coordinator, Waste Minimization Program
Amoco Oil Company
Chicago, Illinois 60680
INTRODUCTION
Petroleum refineries generate oily sludges which can be characterized as oil/water/solids (o/w/s)
emulsions. These hazardous sludges are primarily RCRA listed wastes from both specific and nonspecific sources. Approximately 1.27 x 109 wet kg (1.4x 106 wet tons) of hazardous oily sludges are
generated by the domestic petroleum refining industry each year, according to American Petroleum
Institute (API) surveys, summarized in Table I.1'2 Representing 35% of all non-aqueous wastes
generated annually, these hazardous sludges require expensive management due to land disposal
restrictions. Incineration, best demonstrated available technology (BDAT) for petroleum refining
wastes, can range from $1.00-$3.00/kg ($1000-$2500/ton) for treatment and disposal only, not
including handling at the refinery, transportation, demurrage, etc.
Amoco Oil Company's Texas City refinery generated annually about 118 x 106 kg (132,000 tons) of
hazardous oily sludge during 1987-1989, mainly dissolved air flotation (DAF) float and DAF bottoms
sludges. During these years, the DAF bottoms were considered as "other separator sludges" in the API
surveys before Primary and Secondary Sludges became listed by EPA as non-specific wastes F037 or
F038.
As is typical in the industry, process wastewater at this refinery flows through API-design gravitational separators to remove free oil and settleable solids, then flows through DAF tanks to float out
emulsified oil and suspended solids. Texas City is located in the Gulf Coastal Plain on the Beaumont
Formation, which is dominated by fine clays and silts and receives an annual average rainfall of nearly
1.3 meters (50 inches). This refinery currently has a non-segregated sewer (a sewer system that conveys
stormwater and process water together) that receives fine soil erosion particles via stormwater area
drains during rain events that pass through the API separators to be removed in the DAF units.
Wastewater from the DAF units, free of suspended solids, emulsified and floating oil, is biotreated by
activated sludge to meet permit requirements before discharge.
Table I.    Average Annual Hazardous Oily Sludge Generation: 1987-1989
RCRA
Hazardous Oily Sludges
Refining Industry
Waste Code
Million wet kg
Thousand wet tons
K048
Dissolved Air Flotation (DAF) Float
545
601
K051
API Separator Sludge
355
341
K049
Slop Oil Emulsion Solids
213
235
F037/F038
Other Separator Sludges
90
100
F037/F038
Other Oily Sludges
44
44
F002
Spent Solvents
13
14
K052
Leaded Tank Bottoms
6
7
K050
Heat Exchanger Cleaning Solids
Total
3
3
1269
1400
48th Purdue Industrial Waste Conference Proceedings, 1993 Lewis Publishers, Chelsea, Michigan 48118. Printed in
U.S.A.
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