Comparison of Anaerobic-Aerobic and
Aerobic Lagoon Treatment
DARRELL L. KING, Assistant Professor
DONALD R. BUNN,  Graduate Student
Department of Civil Engineering
University of Missouri
Columbia, Missouri
INTRODUCTION
Anaerobic-aerobic lagoon systems have been used to treat both domestic and
industrial organic wastes with a considerable degree of success (1,2,3,4). The
anaerobic lagoon used in this manner is somewhat analogous to an anaerobic digester in that it is used to reduce the greatest amount of waste in as small a space
as possible, thereby allowing low-cost lagoon treatment to be used where large
areas of flat land are not available. However, the strict environmental control
usually considered essential for anaerobic treatment is not possible in lagoons where
the only parameter which can be controlled to a significant degree is the organic
loading.
In previous investigations of this type of treatment, discussion largely has
been limited to measurements of the biochemical oxygen demand (BOD) and physical features such as suspended solids. This same deficiency also is present in discussions of the polishing or aerobic treatment which by necessity must follow the
initial anaerobic reduction.
In this study an attempt was made to describe the degree and type of treatment afforded by an anaerobic-aerobic lagoon system and to compare this form of
waste reduction with that obtained from the more widely used aerobic facilities.
In addition to the parameters used in previous investigations to describe this type
of waste treatment, measurements of chemical oxygen demand (COD), total
caloric energy, and organic solids were included in this study.
METHODS
The three bench-scale laboratory lagoons used in this study each had a
volume of 20 liters and were of the same type as that used by Azad and King (5).
Light was provided by fluorescent lamps and the photoperiod consisted of 16 hrs of
light and eight hrs of darkness. The synthetic sewage fed the lagoons throughout
the study has been used to maintain balanced biotic populations in a variety of
laboratory treatment facilities (6).
To insure the presence of a balanced biotic population all three units were
seeded with material from two separate municipal lagoons in August of 1964. Initially all three units were operated on a one liter per day fill and draw basis with a
theoretical detention time of 20 days to allow the biotic populations to come into
equilibrium with the environmental conditions of the laboratory. During this period each unit received synthetic sewage at a rate of 170 mg BOD per day, the rate
maintained in the aerobic control unit throughout the study.
In early November the organic strength of the synthetic feed added to the
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