IMPROVING WASTE REMOVAL PERFORMANCE RELIABILITY
OF A WASTEWATER TREATMENT SYSTEM
THROUGH BIOAUGMENTATION
James V. Chambers, Associate Professor
Animal Sciences Department
Purdue University
West Lafayette, Indiana 47907
For the biological treatment of most industrial waste streams, the accepted practice is
to depend on the "ubiquity principle" for the eventual establishment of a microfloral
population. A strongly held premise is that the waste stream will dictate the population
dynamics of the waste assimilation environment and that "nature" will provide the necessary
microbial species. While it is true that the waste stream does influence the population
dynamics of a waste treatment system by the very nature of its available nutrients and
BOD strength, the selection process for microorganisms does not necessarily lead to an
optimal microflora for the best assimilation rate of the pollutant loadings being applied.
It is well demonstrated that "naturally" developed microflora can provide adequate
biological treatment for many waste streams, however, there are still some waste streams
which present specific problems. Dairy wastewaters, for example, are biologically treatable
but historically, those treating these wastewaters encounter a frequent difficulty—"bulking".
The net result is a poor quality effluent attributed to a deficiency in settling solids and an
excessive loss of suspended solids in the discharge. Usually a microscopic examination of the
suspended solids' microflora will reveal an abundance of filamentous bacteria and a variety
of fungi that is responsible for this "bulking" condition. These microorganisms have developed "naturally" in response to the growth environment and to the specific substrate
characteristics of the dairy waste stream being treated. Yet, this microflora does not provide a reliable waste removal capability for the system. It will be the purpose of this paper
to demonstrate that it is possible to influence the population dynamics of various dairy
waste treatment systems' microflora by altering their microbial population and improving
their waste removal performance through bioagumentation.
BIOAUGMENTATION AND POPULATION DYNAMICS
To optimize a biological waste treatment process, several factors must be designed into
the system to achieve desired water purification. These factors are: (1) to provide and maintain a physicochemical environment that minimizes suppressive factors on the waste assimilation process and growth rate of the biomass; (2) to supply adequate aeration and mixing to
meet the respiratory needs of the biomass microflora and to assure stabilization of the organic waste constituents; (3) to promote the establishment of desirable types and quantity
of microorganisms to assimilate the pollutants present in the waste stream; and (4) to control the balance between the BOD being applied and the quantity of biomass needed to
reduce this loading to a desirable level in the final discharge. However, the key to the successful treatment of a given waste stream is the capability of the biomass microflora to
assimilate the waste, convert this waste into cells and suspended solids and form a floe
particle that will settle.
In accomplishing the above, the control of the biomass activity is dependent upon detention time, control of the biomass solids inventory, and the maintenance of a desirable
quantity ratio between the nutrient loading and the biomass solids in the system. For a
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