Organic Concentration and Hydraulic
Loading Versus Organic Loading in
Evaluation of Trickling Filter Performance
ECHOL E. COOK, Assistant Professor
DON F. KINCANNON, Associate Professor
School of Civil Engineering
Oklahoma State University
Stillwater, Oklahoma
INTRODUCTION
During the past several years a great deal of research has been conducted on the
trickling filter process of waste treatment. Lately, a great deal of the research has
centered on the development of new design formulations. The major consideration is
whether the efficiency of a trickling filter is dependent upon the organic
concentration of a waste, or the hydraulic flow rate.
Investigators in the field are in conflict over the relative importance of each of
these two parameters. Velz (1), Germain (2) Galler and Gotaas(3) contend that the
organic concentration of the waste is the controlling factor in the removal of BOD
realized in a trickling filter. Schulze (4,5,6), Eckenfelder (7,8,9) and Etzel (10)
indicate that the hydraulic loading or flow rate is the most important parameter to
consider. Horton (11), Howland (12), Eckenfelder (9), and Sinkoff (13), believe that
detention time or contact time between the waste and the filter biota determines the
removal of BOD realized in a trickling filter. As contact time is related to flow rate,
these may be considered to be the same parameter. Ingram (14) and the National
Research Council (15), indicate that the important parameter to consider is the total
lb of BOD applied to a filter, thus taking into account both the flow rate and the
concentration of the waste.
The purpose of this investigation was to observe the relationship of the organic
concentration of a waste and its flow rate and their influence on the removal of
organics in a trickling filter.
EXPERIMENT, EQUIPMENT AND PROCEDURE
A model fixed bed reactor has been designed and built in this laboratory to
study selected design parameters of fixed bed reactors. The general arrangement of
the experimental fixed bed reactor is shown in Figure 1. Tap water from the city
main enters into a constant head tank from which the flow is controlled by a
rotameter and flows into a wet well. The concentrated synthetic waste is pumped
into the wet well where it is mixed with the tap water to provide the concentration
of waste desired. If it is desired to study an industrial waste in order to gain design
data, then the constant head tank could be utilized as the reservoir for the soluble
waste. Also, in this case, the concentrated feed unit would be eliminated. The waste
is pumped from the wet well to the distribution system. The waste is sprayed over
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