OPERATIONAL TROUBLESHOOTING IN INDUSTRIAL
BIOLOGICAL TREATMENT SYSTEMS
Evan K. Nyer, Vice President
Howard J. Bourgeois, Jr., Vice President
Polybac Corporation
Allentown, Pennsylvania 18103
The basis of biological treatment is the abdity of bacteria to degrade and ingest a wide
variety of organic material. All of the steel and cement that has been constructed for secondary treatment does not do one bit of treatment. The bacteria do the entire job. While
there would be little disagreement with this statement, when a plant needs to improve its
effluent quality engineers turn to the cement and steel not to the bacteria.
Everyone accepts that the right environment must be maintained for biological treatment. The problem is that we too often gloss over the basics. In general, of the plants that
we have worked with, 20% do not maintain or even measure the oxygen concentration in
the aeration tank. One quarter of the plants do not control pH except for effluent discharge limitation. Nutrients are normally ignored. If the plant was originally designed to
add nutrients they are added, most of the time. Not much can be done about temperature
once the system has been budt but design engineers have almost totally ignored temperature
variations as a criteria. As environmental engineers we have done a great job of teaching
people to concentrate on the equipment but have subsequently taught them to assume too
much about the reaction itself. To optimize the installed equipment operators must be
made to realize the reasons for addition of nutrients and maintaining pH and dissolved
oxygen. A living organism is doing the job for them not the tanks and pipes.
Engineers and operators too often lose sight of the living nature of a biological treatment system. Models and designs assume the correct environment, the correct bacteria and
steady state conditions. It is taken for granted that the correct pH, temperature, NH3,
P04, micro nutrients, and 02 level will be maintained in the system. It is assumed that
the bacteria will naturally want to be in the system and stay in the system no matter what
we do to them. Finally, it is assumed that nothing will change during the operation.
We also assume too much about the bacteria. The bacteria must also be considered one
of the basics in biological treatment. Normal operations subject the bacteria to changes in
02, pH, temperature, organic load, specific chemicals, etc. The limitations of many wastewater treatment systems is how fast the bacteria can change to the new conditions. But,
no matter what, we assume that bacteria wdl naturally adapt to these conditions.
The following case histories give full scale evaluations of the use of "better" bacteria
in conjunction with the natural population. The three examples will cover an aerobic lagoon,
activated sludge plant, and filamentous growth in a municipal plant.
In operations of secondary wastewater treatment plants we must re-emphasize the basics
of biological degradation. The following data will show that the bacteria must be included
in this emphasis of basics.
"BETTER" BACTERIA-SELECTIVE ADAPTATION AND MUTATION
The process of selective adaptation and mutation for obtaining microbes with specialized
capabilities is not novel. However, the process of applying this technology to waste treatment on a commercial scale with effective results is relatively new. Through the process of
selective adaptation, microbes are selected from nature based on their ability to service
environments containing relatively uncommon or unnatural organic compounds and then
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