MICROBIAL DENITRIFICATION OF A WASTEWATER CONTAINING
HIGH CONCENTRATIONS OF OXIDIZED NITROGEN
T. B. S. Prakasam, Project Manager
Metropolitan Sanitary District of Greater Chicago
Cicero, Illinois 60650
R. C. Loehr, Director
Environmental Studies Program
Cornell University
Ithaca, New York 14853
INTRODUCTION
With the enactment of the Federal Water Pollution Control Act PL 92-500 amendments in 1972, greater emphasis is being placed on nutrient control in many wastes.   Although considerable effort has been made in understanding the problems associated with
nutrient management and control of dilute wastes such as domestic wastewater, information on the technology for control of nutrients in highly nitrogenous wastes, such as
those from poultry raising and egg production facilities and swine production operations,
is relatively sparse.   This has been due to the diverse and relatively isolated nature of agriculture in the past.   Farms were of small size and the individual farmer was able to dispose of the wastes on land which was readily available for growing crops, by taking advantage of the nutrient content of these wastes.   However, in recent years in response to the
increased animal production, changes have taken place in livestock production, feeding,
slaughtering, transportation and processing operations.   These changes have resulted in
confinement feeding of livestock and in increased numbers of animals per production unit.
The trend toward controlled and enclosed facilities is virtually complete for smaller animals, such as hens and broilers.
In sharp contrast to the past, the modern confined and more mechanized animal production facilities generate large quantities of wastes on smaller areas of land.   The nitrogen content of poultry waste alone in 1970 is estimated to be about 9 x 106 lb per day.
The high quantities of waste and concentration of nutrients are a potential source of
ground and surface water pollution unless appropriate measures are taken.   Estimates of
the amount of nitrogen reaching the surface or ground waters from this source are not
available.   With the growing concern for maintenance of our waters, greater emphasis is
being placed on nutrient control with all wastes.   The technical and economic feasibility
of nitrogen control of animal wastes needs further investigation.   The challenge is to develop processes that can remove undesirable components from these wastewaters as economically as possible.   The challenge becomes even larger when one contemplates that
animal waste treatment systems must be able to (a) accept and process concentrated and
intermittent loads, (b) possibly operate in the open and under wide seasonal temperature
variations, and (c) perform satisfactorily with little maintenance and skillful operation.
In view of the highly concentrated nature of these wastes, extremely high removal efficiencies (>99%) must be obtained in order to meet effluent criteria for their discharge
to surface waters.   In addition the EPA effluent guidelines for feedlot operations call for
no discharge of animal wastes to surface waters.   The high treatment efficiencies and
guidelines require close evaluation of combined treatment-land disposal alternatives.
Over a period of 5 years studies have been conducted in the Agricultural Waste Management Program of Cornell University to investigate and demonstrate the applicability
of sanitary engineering fundamentals to the design of treatment systems for poultry
wastewaters and to develop the necessary design parameters for systems to remove excess
nitrogen from these wastewaters.
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