Technical and Legal Controls for the
Disposal of Animal Wastes
RAYMOND C. LOEHR, Professor
Agricultural and Civil Engineering Department
Cornell University
Ithaca, New York
INTRODUCTION
A number of alternatives exist for the disposal of treated or untreated animal
wastes: 1) disposal of both the liquid and the solids on the land, 2) combustion of
the solids with disposal of the liquid and/or residual solids to the land, and 3) discharge of the wastewater to receiving waters. Treated and untreated animal
wastes and wastewaters can contain large concentrations of solids, oxidizable
material, dissolved nutrients and salts. All the above alternatives contain the
possibility of water pollution either from direct discharge to receiving waters,
from runoff of lands used for liuqid or solids disposal, or from contamination of
ground water after land disposal.
A number of states have or are in the process of developing criteria to control pollution caused by animal wastes. Effluents from animal production facilities will be expected to meet the stream standards being set. It is the purpose of
this paper to: 1) illustrate the expected quality of treated and untreated animal
wastewaters, 2) discuss the type of technical processes that will provide the effluent quality that will be required when animal wastewaters are discharged to receiving waters, and 3) comment on the alternatives of handling and treating animal wastes as a liquid or a solid waste.
QUALITY OF ANIMAL WASTEWATER
The population increase in the nation and the increase in per capita consumption of meat has caused greater numbers of animals to be raised. An increase in the number of large scale animal production facilities and the number
of animals per facility has occurred as the animal producers have attempted to
increase profits by utilization of mass-production techniques. Confinement feeding of animals has concentrated large volumes of waste in small areas. Untreated
animal wastes from such facilities have been the cause of surface water pollution
and have been implicated in several cases of ground water pollution (1,2).
Animal wastes are defecated in semi-solid form and there is considerable
logic in treating and disposing of these wastes as a semi-solid material rather than
adding water for liquefaction before treatment and disposal. The latter approach
requires the treatment of both the animal wastes and the contaminated water.
However, because of difficulties in the handling of animal wastes as a solid material, liquid waste handling, treatment, and disposal are common at many animal production facilities. Experimentation continues on techniques to reduce the
quantity of water used in the facilities.
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