Treatment of Steel Drum Processing Wastewater
RILEY N. KINMAN, Associate Professor
JACK MUSTERMAN, Graduate Student
Department of Civil and Environmental Engineering
University of Cincinnati
Cincinnati, Ohio 45221
PAUL ARELL, Engineer
U.S. Public Health Service
Denver, Colorado
INTRODUCTION
The steel drum reconditioning industry in this country is 40 years old and has done
much to conserve steel and to minimize the solid waste disposal problem caused by used
drums. Recycling is the reason for existence of the industry. An 18 gauge, 55 gallon steel
drum can be recycled up to 15 times. In 1968, 20 million new drums were manufactured,
and 45 million drums were reconditioned. This permitted the recycle of one million tons
of steel (1).
The industry faces problems of air and water pollution because of the trend of the
drum manufacturer to produce a thin-walled, non-reconditionabledrum. Liquid wastes
generated contain residues of materials originally in the drums (approximately 5 pounds
per drum), a sodium hydroxide cleaning solution, detergents used in the cleaning solution,
and sanitary sewage from the plant. Residues left in a drum may be anything which can be
shipped and stored in 55 gallon steel drums including oils, solvents, paint, varnish, ink,
dyes, adhesives, acids, alkalies, antifreeze, resins, detergents, wax, honey, and even tomato
paste.
The objectives of this work were to: 1) Characterize drum reconditioning wastewater;
2) Develop a physical-chemical tertiary treatment method for this wastewater; 3) Evaluate
the effectiveness of this treatment method on a bench pilot plant scale; 4) Determine the
treatability of this wastewater by an aerobic biological process; 5) Evaluate the effects of
various pretreatments on a completely mixed activated sludge system on bench scale; and 6)
Develop cost estimates for application of the physical-chemical treatment process selected.
DESCRIPTION OF THE DRUM PROCESSING OPERATION
Two general processes are used for recondition of steel drums. One is called the open
head process and the other used for closed head drums is called the closed head process. A
flow diagram for both types of processes is shown in Figure 1. Two types of wash are
available, but most operators use an alkaline wash system rather than an acid wash. Liquid
wastes contain residues of materials originally in the drums (approximately five pounds per
drum), a caustic soda cleaning solution, iron fillings from the blasting operation, industrial
detergents, and a small volume of sanitary sewage from the plant. Drum residues include a
wide variety of oils, hydraulic fluids, paint, varnish, solvents, dyes, coating materials,
detergents, wax, foodstuffs and anything else which can be shipped or stored in 55 gallon
steel drums.
The open head process is essentially a dry one except for the upending operation, which
dislodges the drum residue. Painting causes a unique wastewater problem whenever the
paint pits are washed during cleanup. The closed head process is a wet process and
contributes most of the waste stream. Preflush and the washing operation transport the
drum residue into the wastewater stream. Chaining in a caustic and detergent bath loosens
the remaining residue which is dumped at the up ender. Overflow from the cleaning solution
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