ANAEROBIC FERMENTATION OF ANIMAL WASTES:
A KINETIC DESIGN EVALUATION
Gary R. Morris, Research Engineer
Environmental Sciences Division
Envirex, Inc.
Milwaukee, Wisconsin 53201
William J. Jewell, Associate Professor
Raymond C. Loehr, Professor
Department of Agricultural Engineering
Cornell University
Ithaca, New York 14850
INTRODUCTION
To date (1977), despite widespread application of the anaerobic fermentation process
in municipal wastewater treatment, limited information has been made available concerning the process fundamentals of anaerobic systems in the treatment of animal wastes.
Without such information, a quantitative basis of design, ue„ a mathematical model, cannot be developed which will be universally applicable to the prediction of the overall process behavior for different animal wastes.
The design of the anaerobic process in the past has been based on the engineering judgment of the designer and on past experiences in the waste management field regarding the
observations of successful performances from similar situations.   In many instances, these
observations were obtained through laboratory or pilot plant studies which produced satisfactory results.   This design approach has been common in all branches of engineering and
agricultural waste management is no exception.   Although these efforts have been responsible for important developments in the waste treatment field, the limitations of the applicability of these past observations should be recognized because of their inability to provide
a quantitative basis for design.   Therefore, attention should be focused on a more unified
or even a deterministic approach to process design.
During recent years, substantial research efforts have been directed toward the attainment of a more complete understanding of the factors affecting the anaerobic fermentation of sewage and industrial wastes.   Although not directly applied to animal waste
treatment, significant progress has been made in formulating design and operational criteria on a more fundamental basis rather than on past performance observations.   A survey
of design approaches presently being used to describe biological treatment processes indicates that kinetic reaction relationships have been successful in predicting the performance
of anaerobic processes treating municipal sludges [1,2].   The extension of this design approach to the field of animal waste treatment could provide a means for unifying the
available data and serve as a quantitative basis in describing future process performances.
On this basis, it was concluded that an investigation of the fundamentals of the anaerobic process would permit the development of kinetic reaction relationships that can be
used to predict the operating and design criteria for anaerobic fermentation systems treating animal wastes.   The comprehensive laboratory and theoretical investigations were designed to achieve the following objectives:
1. To determine the biodegradability of animal wastes.
2. To evaluate the effects of process design or operational variables on the anaerobic
fermentation process.
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