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Some Problems Encountered in Spray
Irrigation of Canning Plant Waste
R.  A.  CANHAM
Sanitary Engineer
National Canners Association
Washington, D. C.
The two types of waste generally produced from canning plants
are liquid and solid. Liquid wastes originate from (1) cleaning and
washing food products, (2) equipment and floor washing, (3) processes
in which water has a functional use as a means of hydraulic transportation, extraction, cooling, etc., (4) spillage or wastage of liquid
foods or ingredients, (5) concentrates, and (6) condensates. Solid
wastes originate either from the food material itself (rejects, trimmings, inedible parts, adhering soil) or residues from unit operations
(extraction, etc.). Conversion of certain solid wastes to usable byproducts may be economically feasible. Except for a few cases the concentration of soluble organic materials in liquid wastes does not warrant
by-product recovery.
The subject of food canning waste disposal of the liquid waste is
one which presents practically unlimited problems due to a number
of factors and, therefore, requires special attention to each individual
canner's situation.
The first factor involved is that the majority of canning operations
are seasonal in nature, although some few are practically year round.
This means that a waste treatment system must usually be relatively
low in capital investment and always reasonable in operating cost.
Second, the waste characteristics from each product are different
from those of other products. Each type of canning waste has a different range of pollutional potential as measured by the organic content
of the waste. This strength is commonly reported as 5-day biochemical
oxygen demand (B.O.D.). As is widely known, it is not a completely
satisfactory test but is the best available at the present time. In
actuality, the B.O.D. is used as a comparative index of the waste
strength and is valuable because some regulatory agencies require treatment to a certain B.O.D. level.
For purposes of comparison the strength of domestic waste in terms
of B.O.D. is usually near 200 p.p.m., while the range of canning waste
120