Basic
processes lie a t the NI base of purification of polluted xvaters. This symposium has been ar-
Biological
ranged to draiv from basic biological sciences the concepts and information necessary in understanding and interpreting the complex phenomena related to the purification of polluted Xvaters. The activities of the microorganisms resulting in purification of polluted \vater arc of biochemical nature; microbial adaptations. associations, and antagonisms, hoivever: form the essential background for the understanding of performance of the biochemical activities of microorganisms. Polluted xvaters for the purposes of this symposium include selvage and industrial \Tastes and surface \caters receiving these wastes. The symposium applies to the purification of such waters by artificial treatment processes as well as in natural stream purification, although the approach and the emphasis is not from these aspects. It is recognized that, for certain industrial \vasres: biological treatment is neither feasible nor advisable. I n this category fall primarily inorganic wastes such as those derived from metal pickling and plating processes. Even these wastes, however, are sometimes discharged into municipal seivers and into streams and affect the biological processes. More commonly: industrial bvastes contain a mixture of inorganic and organic compounds, either of lvhich may have a biological inhibitive effect. T h e problems of tolerance levels and biological adaptations, spergistic and antagonistic effects of combinations of these compounds, become of paramount importance. Many such wastes contain synthetic compounds not commonly found in nature in animal and plant residues. New industries such as antibiotics, synthetic rubber? and nuclear power create new problems in developing suitable treatment processes and evaluating their effects on biological processes.
ICROBIOLOGICAL
Principles
Microbial Adaptation..
......
1404
Orville Wyss
Microbial Associations Antagonisms.
and
... . ... . . .
R. Weindiing Discussion Robert
1407
S. lngols
Transformations of Carbon Compounds b y Microorganisms..
. ... . ... .. .
141 1
Walter J. Nickerson Discussion: Sam R. Hoover
Biological Transformations of Nitrogen Compounds. .
..
1421
Transformations of Sulfur b y Microorganisms.
1429
C. C. Delwiche Discussion. G e r a r d A. Rohlich
.. .... .
Robert L. Storkey Discussion: Kenneth L. Ternpie
Biological Formation of Methane..................
1438
H. A. Barker Discussion: A. M. Buswell
Microbial Decomposition Hydrocarbons..
of
. ...... . J. B. Davis Photosynthesis in the Algae. . .
1444 1449
Robert W . Krauss Discussion. C. Mervin Palmer Discussion: William J. Oswold and Harold B. Gotaas
Division of Water, Sewage, and Sanitation Chemistry, 128th Meeting, ACS, Minneapolis, Minn., September 1955.
There is still another group o f industrial wastes that does not raise any of these special problems and that contains normal components of organic residues. I n this category belong the canning. dairy, packinghouse, and pulp and paper wastes. For such Jvastes, \vel1 established selvage treatments are applicable, and there is only the question of finding the limits of load application for most economical methods. Even in the biological treatment of domestic selvage which has been under investigation for a longer period. our information is somewhat superficial. M’e have no detailed insight of the complex biological reactions of a great variety of compounds brought by a host of microorganisms. In general there is a complete and spontaneous mobilization of biological populations working in a smooth integrated assemblylike fashion. The details regarding the succession of the organisms, effect of one group on the activities of the others, sequence, interactions: and interdependence of one reaction on another, and intermediate and alternate pathlvays are unknoxvn to us. T h e result is that with present information we are not able to exercise complete control on the processes, nor approach difficulties except by empirical methods. T h e problems of biological stabilization of pollutional materials is similar to those dealing with the decomposition of organic residues in soils except that the organic materials are higher in concentration and more labile than those found in soils, and consequently the rates of reaction are higher. Artificial intensification of the natural processes in Ivaste treatment is more feasible and imperative for reasons of economical methods of disposal of ivastes than they are in soils. Both aerobic and anaerobic processes are utilized depending on the condiLions and requirements. H. Heukelekian VOL. 48, NO. 9
SEPTEMBER 1956
1403
