Co-operative Research in Problems of Purification
Conclusion of Mr. Wolman’s Paper on This Subject Read Before Chemical and Bacteriological Section of A.W.W. A.—Discussion of Subject by Members
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(b)—Filtration.—The internal forces within a sand filter bed are of greater magnitude than is generally realized. Experience in Maryland with a number of peculiar phenomena in filter beds has disclosed a starting variety of forces released in filter beds, which appear to be intimately connected with the character of sand and of applied water. The appearance of internal contraction in a sand bed of such strength that the surface area of the bed may be reduced by more than five per cent, of its original area is of importance in calling attention to the unsolved problems concealed within the bed.
If we consider the whole principle of filtration as founded upon “a sort of instability, both chemical and biological, (and physical—A. W.), in the behavior of matter in solution or in suspension, when spread out in thin films over surfaces, or flowing in fine filaments through interstilial capillaries of constantly varying cross-section” (3) we obtain some idea of the intricacy of the problems. That these problems are of more than academic interest has been clearly demonstrated in the difficulties encountered in the shrinkage of sand beds, in their selective action upon bacteria, in the adsorption of materials in water softening plants, in the sudden discharge of sludge of chlorine taste where chlorine is applied before filtration, and in many other phenomena. The researches of Dunbar (3) and Baldwin-Wiseman (3) on the variations of surface tension within a sand bed and their conclusion that the elimination of a dissolved salt by fdtration is inversely proportional to the degree of concentration of the solution mark only the beginnings of the studies on internal forces. Our own works on the varynig adsorptive capacities of different sands and Hannan’s observations (4) on the effect of surface electrical charges of sands and of bacteria indicate the promising possibilities of more research in filtration.
(c)-Chlorination—Sanitarians have established definitely that waters may be made safe for potable purposes by chlorination. The water works official, however, must go a step further. He must make the water potable in addition to safe. If the water is unpalatable and objectionable because of tastes and odors, then the problem of chlorination may not be considered as solved. It is only a few years since the conception of the mechanism of chlorine treatment has undergone some modification from the simple hypothesis of direct oxidation. But in this comparatively short period, a series of questions have arisen which are still imperfectly answered.
In this field again we must have recourse to highly technical investigations to aid us in clarifying our concepts of chlorination processes and in controlling their operation. Even today it is difficult to answer definitely whether the action of chlorine is physical, physico-chemical, or chemical, whether its action is selective for different types of bacteria and, if so, what the causes for such selection are. The action of other disinfectants is elective and their toxicity is dependent upon their position in definite ionic series and upon the characteristics of the different bacteria, such as their response to Gram stain. The surface character of different classes of bacteria show a marked influence upon their behavior under different conditions.
Where we attempt to treat raw waters of complex organic and inorganic content, our present methods of control are entirely empirical and not infrequently unsuccessful. The causes of tastes with low doses and the absence of tastes, at times, with execessive doses of chlorine are still in the category of the unknown. It is not a solution of the difficulty to state that tastes and odors may be prevented by proper regulation of applied chemical, for the terms “proper regulation” are indeed broad in interpretation. Proper chlorination control, on the contrary, would seem to be possible of attainment only after a complete understanding of the details of the complex disinfection processes has been reached. May we not call upon this Association to take the lead in the initiation of these studies?
(3)—Baldwln-Wlseman, W. R., Statistical and Experimental Data
on Filtration, Proc. Institution of Civil Engineers, Vol. CLXXXI., 1909-10.
MR. POWELL-I have had the privilege of reading this paper before its presentation at this meting and I was very greatly surprised by Mr. Wolman’s efforts. I think the time is ripe not only for this association or this section, but for all scientific bodies in America to take the same advanced step along the line of cooperative research. The problems which Mr. Wolrnan had mentioned I feel (and I am sure that all who are talking water purification realize) are real problems and not imaginary ones. For the past fifteen years these problems have been presented to me and I think that if we could get together in this section, in a discussion and follow out the lines that Mr. Wolrnan has spoken of this morning, we would go far along the lines of co-operative research in America.
MR. Weston—1 would like to say a word of praise for Mr. Wolman’s paper. I think most of us, especially these who are approaching the age of Dr. Bartow and myself, who have graduated from college before the date of modern physical chemistry, do not realize the vast field of physical chemistry and its importance to our water works. Only the other day I was talking to Professor Cook, whom you know, and he said “we have gone just about as far as we can in analytical chemistry in the field of water works operation and water purification. We have now got to turn to physical chemistry to help.” 1 think that is true. All these problems which Mr. Wolrnan mentioned this morning are very pertinent, and I think, are problems, for the solution of which we must look to physical chemistry more and more, and it is for these younger men who have had a chance to secure training in physical chemistry, which I had not time to aquire after graduating but which I know Dr. Bartow has acquired, to whom we must look to for health.
THE Chairman—I am afraid Mr. Weston flatters me when he says I acquired a knowledge of physical chemistry.
MR. Goodell—From the point of view of the Publication Committee, we ought to get some good information out of Mr. Wolman’s paper, and we thought that paper was admirable proof of the conclusion that we had reached, namely, that some kind of a council should be appointed which in the next year might get together and suggest how to do these things that Mr. Wolrnan suggested should be done. That is all that could be done in a year. Now, gentlemen, have you any suggestions that you can make that can be passed on to the council.
MR. Orchard—Speaking a word of commendation of the very scholarly paper that Mr. Wolrnan has presented, it is a pity that it was heard by so few in comparison with I he numbers in attendance at the convention. It is quite easy to get together a few statistical facts and get up a talk about them, but when a gentleman gives the thought and study to a paper, as Mr. Wolrnan has done, surely a large number should hear it. We must not let these highly technical matters scare the water works man, and if they would listen to a paper like Mr. Wohnan’s they would appreciate more what the technical man is doing. Mr. Wolrnan made certain specific recommendations and there was passed, at the convention yesterday, a motion, authorizing the appointment of a council of research, and I make the motion, if in order:
“That it may be the sense of this section that Mr. Wolman’s paper be referred to the council with the endorsement of this section, to do whatever they can to investigate the possibility of co-operative research before the next convention.” (Carried.)
THE Chairman—I have not attended one of these meetings for three years and apparently we should have some action taken. Without the organization we can elect a secretary and chairman of the section unless some other provision has been made.
MR. Rosenthal—I believe that this is really a splendid opportunity at the present time. There are quite a few at present to perpetuate the organization. I take pleasure in nominating Dr. Edward Bartow as chairman of this section.
DR. Bartow—I have already been chairman and the honor should be passed around. I was the first chairman, and I think someone else should be appointed. I think we could have a nominating committee appointed, or else we can offer to this convention, nominees for the secretaryship, and the membership of the committee. I think we ought to have a nominating committee appointed. Will you nominate officers from the floor or will you nominate and elect a nominating committee?
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MR. WESTON-I move that the chairman appoint a nominating committee to retire and nominate candidates for such offices.
THE Chairman—The city of Dallas has requested a member to present a paper on the operation of the water filters they have, and Mr. Rosenthal was sent here by the city of Dallas to give that paper before you gentlemen who are specialists in this matter. It is impracticable to read the papers anywhere else. This city has taken this matter up and we have requested you gentlemen to hear this matter and discuss it because, as I say, the city of Dallas desires an opportunity of presenting this matter to the gentlemen of this organization in this manner. Gentlemen, we have five more papers. We cannot finish this before twelve or twelve-thirty, so it seems to be desirable to have an afternoon session. There is a motion here that the chair appoint a nominating committee to report on officers for the coming year, also to report to the session this afternoon at two o’clock. (Carried).
(To be continued)