Influence of Cesium Ions on Oxygen Demand of Sewage JACOBE. SCHMIDT AND JOHNC. KRANTZ, JR., Maryland State Department of Health, Baltimore, Md.
T
HE influence of the presence of various ionic and molecu-
cesium ions were directly responsible for the retardation of oxidation.
lar species upon the acceleration of the sedimentation of sewage has been the subject of many investigations. Floc-forming chemicals, as represented by the salts of the trivalent metals, have proved their usefulness in accomplishing this purpose. A survey of the literature, however, reveals little systematic investigation directed to the determination of the positive or negative catalytic oxidation influence of the presence of various ions on raw sewage. Greenfield et al. (I) in their comprehensive studies on the biochemical oxygen demand test observed the effect of certain inorganic salts used in deoxygenation experiments. They showed that the total oxygen demand is increased by increasing the concentration of inorganic salts. It was observed that sodium bicarbonate alone produced a n effect which, however, was markedly increased by the presence of magnesium, calcium, and potassium salts. The authors set forth to study the influence of various ions upon the oxidation of sewage, with the purpose of determining whether a relationship existed between the influence of the ions on the oxidation of sewage and their periodicity. This report is concerned particularly with the influence of cesium ions.
TABLEI.
SERIES
A B C
(Averaged data in cc. of 0.025N sodium thiosulfate) No. OF DILUTION CONCENTRATION OF CESIUM CHLORIDHI: or S E W A Q 0 ~.0 M 0.001 M 0.0002M . 0.003 iM DETNS. 1:25 6 0 0.5 ... 1:50 1.1 10 1.6 3.2 3.6 ... 1:50 7 3.4 3.6 7 1:40 3.0 4.0 ... 1:50 4.4 ... 6 4.3 ... 1:50 0 4.9 ... 4.5 5 4.0 ... 3.6 1:50 0.3 1:50 5 0.2 0.3 ... 5 4.8 5.3 5.6 1:50 6 1:50 6.9 7.3 6 1:50 3.2 ... 4.1
... ...
...
D E
F G H I J
...
... ... ...
K
.
.
I
.
I
.
TABLE 11. INFLUENCE OF CESIUMCHLORIDE ON DETERMINATION OF OXYQEN CONTENT OF DISTILLED WATER NO. OF SERIES DETNS.
A
9
C D
6 14 5 6 5
n
E F G
EXPERIMENTAL PROCEDURE The experiments were conducted on raw sewage collected in the vicinity of Baltimore. The specimens were strained through cloth prior to dilution with distilled water, previously brought into equilibrium with air. Dilutions of sewage for the control and test experiments were always drawh from the same reservoir. The salt to be added was dissolved in about 20 cc. of diluted aewage and mixed with the specified volume of diluted sewage contained in a 2-liter volumetric flask. The samples containing the salt and the control dilutions were transferred by siphon to bottles of 250 cc. capacity, respectively. The glass stoppers were inserted after the exclusion of all air bubbles. The bottles were then provided with a water Real by inversion in a trough of water. Sevenday incubation periods at 20’ * 0.5’ C. were employed. After this period the residual oxygen was determined by the Winkler method ( 2 ) using the usual precautions t o exclude air bubbles. Similar control experiments were conducted wlth distilled water to determine whether the presence of cesium chloride affected the chemical procedure employed to determine the residual oxygen. The results expressed in 0.025 N sodium thiosulfate are set forth in Tables I and 11. The tables show that the presence of cesium chloride in the quantities employed, in practically all instances, exerts a retarding influence upon the oxidation of sewage as indicated b y a n increased residual oxygen content. Preliminary experiments with rubidium chloride indicate that a similar infiuence can be produced by the presence of this salt. The degree of influence is smaller however. The observations made with distilled water reveal that the presence of cesium chloride in distilled water does not influence the titration figures. It is therefore concluded that the change observed was due to the action of the alkali salt on the sewage. As chlorides are normally present in significant quantities in the sewage, i t is not likely that the retardation was caused by the chloride ion. It appears therefore that
IXFLUENCE OF CESIUMON OXYQENCONSUMPTION OF SEWAQE
5
CONCENTRATION OF CESIUM CHLORIDE: 0.001 M 0.0002M 0.003M 6.1 6.1 ... 5.4 5.4 ... 9.0 9.0 9.0 8.7 8.65 ... 7.4 7.4 7.0 7.0 . ... 7.7 7.6
O.OM
... ... ... .....
... ... ... ...
At present the authors are not in a position to state whether the influence of the cesium ions was directly on the organic matter in the sewage, retarding its oxidation by agglutination of particles or other physical phenomena, or whether the action was bacteriostatic, reducing the activity of mineralizing bacteria present. Wright and Graham ( 3 ) have shown that cesium chloride injected into mice before implantation of tumor cells produces a deterrent effect on protoplasm, doubling the number of failures in the growth of the implanted cells. Yet i t is of interest to note that pharmacologically rubidium and cesium resemble potassium, and in the excised heart of the frog either may replace potassium. Further experimental work will be required before a definite hypothesis can be formulated regarding the role of the cesium ions in the mechanism of retarding oxidation. COXCLUSION The presence of cesium ions in concentrations of the order of magnitude of 0.001 M retard the oxidation of raw sewage. LITERATURE CITED (1) Greenfield et al., IND. ENG.CHEM.,18, 1276 (1926). (2) Winkler. L. w.. Be?.. 21.2843-54 (1888). (3j Wright,‘A. W.; and Graham. C.’F., Am. J . Path., 9 (Suppl.), 789 (1933). R E C E I V ~September D 1, 1934. The expense of this investigation waa defrayed by a grant from the Bureau of Sanitary Engineering of Maryland upon the recommendation of Abel Wolman, Chief.
NEW G E W SYNTHETIC RESINSERIES. A new class of polymerized vinyl compounds rharacterized by clear, colorless appearance and a com lete absence of odor has atpeared on the German market un&r the trade name “Acronal. The properties claimed for Acronal resins suggest a wide field of uses. 171
