Based on the above estimate, sewage disinfection for a railway coach which used 10 cubic feet per day for toilet flushing will cost about 2 cents per day. The cost for steamers will probably be somewhat higher owing to the greater amount of water used per toilet flush.
An estimate of 5 or 10 cents per closet per day would seem reasonable. The steamers could, of course, reduce this considerably by substituting railway toilets for their present equipment.
That is, briefly, a description of the manner in which the tank works.
Mr. Powell. What temperature is the water?
Mr. Frank. We have been experimenting with the tank since January, and in none of our tests has the temperature at which discharge began been lower than 190° F., and that has only been when I have put steam in at such a high rate that it rose through the water so rapidly to the surface as not to condense as in the usual adjustment. In practically all of the experiments where I have so adjusted the steam valve—mind you, this has an automatic adjustment, too—as to cause the time of heating to be about 15 or 20 minutes, the temperature has always been between 200 and 212, practically boiling, always above the killing temperature for pathogenic organisms. I should say it was, roughly, about——
Mr. Powell. One hundred and seven?
Mr. Frank. No; about 160° F., which is equivalent to 60° C. The device may be regulated so that the discharge is never under 200. I think that the effect of the temperature can be illustrated by the results of our tests. We have never in any case been able to recover B. coli from the effluent, except once, in a great many tests. I have forgotten how many there were. In this one case I put the steam at such a high pressure that the discharge took place in only two or three minutes. Now, it is possible, in the manner of installing the device upon a vessel, to make it absolutely impossible for that to take place. I say that because I have been operating with 100 pounds steam pressure in Washington and reducing it down to about 5; and it is always possible on some vessels to make the line carry anything you want by a proper reducing valve. And if this line can be brought to somewhere about 10 to 15 pounds per square inch it is physically impossible for the discharge to take place in anything less than 10 or 15 minutes.
As regards what has been done toward installing the device on vessels, this experiment has been almost entirely due to the courtesy of Col. William Livingstone, president of the Lake Carriers’ Association. As you will remember, some time ago he offered to provide for the commission one or more vessels for experimentation. He has now made good that promise, and last week I was in Cleveland, and initiated the installation of the apparatus with which I have been experimenting in Washington since January upon the D. G. Kerr, just recently off the ways, and now completed, I believe, from what I heard in Cleveland. The installation of the device will be completed about to-morrow, and the first trip of the vessel is scheduled to begin Wednesday morning. I expect to make that trip on her. In regard to the future experimental work with the device, I do not think it ought to be too quick. I think we ought to take a fair amount of time to satisfy ourselves as to the manner in which the device works. I do not think one or two trips are enough to tell whether it will work or not. We have been experimenting with the device upon a stationary basis at a pumping station. That means no motion of the device; and it is certainly desirable to determine how it will act on a rolling vessel, and that will be the object of the present experiments during the coming season.
Mr. Mignault. Do you foresee that the rolling of the vessel will make any difference?
Mr. Frank. At present I can not see any definite trouble that is likely to result. With the rolling of the vessel I foresee that when the tank is half full the surface of the water in the tank may be caused to sway at an angle depending upon the rolling of the vessel.