IMPROVING EFFLUENT QUALITY
OF PETROCHEMICAL WASTEWATERS
WITH MUTANT BACTERIAL CULTURES
John A. Christiansen, Environmental Engineer
Sybron/Biochemical
Birmingham, New Jersey 08011
Philip W. Spraker, Operations Manager
Sybron/Biochemical
Salem, Virginia 24153
The petroleum industry has made significant expenditures in equipment, chemicals and
operating expertise to produce high-quality effluents. Among these expenditures for operation have been amounts for mutant bacterial cultures. The use of these cultures is quite recent, dating to less than 10 years ago, and the technical data available to evaluate their
success are still limited.
This chapter presents some of the claims of bioaugmentation, a description of the development of such cultures and selected case studies of field applications. The case studies
detail the degree of success of the application and limits to the use of such cultures.
The basic reasons for using these materials are (1) meeting the requirements of their
NPDES discharge permits consistently at a time when these industries are closely inspected
by regulatory agencies; and (2) establishing increased control of the biological operations
system. The specific benefits are:
1. improving removal of toxic or difficult to degrade compounds of petrochemical wastewaters, such as high phenols, polynuclear aromatics, amines, ammonia, sulfides, alcohols, oil and grease;
2. achieving consistent effluents with widely ranging influent organic levels;
3. improving settleability of biological solids;
4. achieving consistent nitrification;
5. correcting low or inconsistent MLSS (biomass);
6. controlling foams, including Nocardia type (old sludge, brown, foaming); and
7. significant cost savings.
Operating cost savings include decreased use of polymer in the secondary clarifier, reduction
of steam added to MLSS to maintain optimum temperatures, reduction of defoamer added
to aeration basins to control excessive foaming, and reduction of aeration costs where an
improvement in oxygen transfer and dissolved oxygen was recorded. This phenomenon is
almost always associated with removal of foams from basins where floating surface aerators
are used.
REFINERY WASTEWATER TREATMENT PLANTS [1]
Refineries are the most common petrochemical operations with biological wastewater
treatment systems. General aspects of refinery wastewater treatment plants are shown in
Table I.
DEVELOPMENT OF MUTANT BACTERIA
Bichem mutant bacteria are developed through simple in situ genetic engineering. This
method of conventional genetic engineering is believed to amplify a specific character of
the parent bacteria isolated from an industrial waste stream.
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