"Second.—Hydrated ferrous oxide is a deodorizer.
"Third.—By this process the soluble organic matter is reduced to a condition favorable to the further and complete purification by natural agencies.
"Fourth.—The effluent is not liable to secondary putrefaction."
Mr. Alfred E. Fletcher also investigated the process subsequently, and reports as follows:
"The treatment causes a reduction in the oxidizable matter in the sewage, varying from 60 to 80 per cent. The practical result of the process is a very rapid and complete clarification of the sewage, which enables the sludge to separate freely.
"It was noticed that while the raw sewage filters very slowly, so that 500 c.c. required 96 hours to pass through a paper filter, the electrically treated sewage settled well and filtered rapidly.
"Samples of the raw sewage, having but little smell when fresh, stank strongly on the third day. The treated samples, however, had no smell originally, and remain sweet, without putrefactive change.
"In producing this result two agencies are at work, there is the action of electrolysis and the formation of a hydrated oxide of iron. It is not possible, perhaps, to define the exact action, but as the formation of an iron oxide is part of it, it seemed desirable to ascertain whether the simple addition of a salt of iron with lime sufficient to neutralize the acid of the salt would produce results similar to those attained by Webster's process.
"In order to make these experiments, samples of fresh raw sewage were taken at Crossness at intervals of one hour during the day. As much as 10 grains of different salts of iron were added per gallon, plus 15.7 grains of lime in some cases and 125 grains of lime in another, and the treated sewage was allowed to settle twenty-four hours; the results obtained were not nearly as good as the electrical method."
During the present year a very searching investigation of the merits of various processes of sewage treatment has been made by the corporation of Salford; among others of my electrical process. As the matter is at present under discussion by the council, I am not in a position to give extracts from the reports of the engineers and chemists under whose supervision and control the work was done, but I may go so far as to say that the results of my system of electrical treatment have proved its efficiency and applicability to sewages of even such a foul nature as that of Salford and Pendleton. The system was controlled continuously for the corporation by Mr. A. Jacob, B.A., C.E., the borough engineer; Mr. J. Carter Bell, F.I.C., etc., county analyst; Messrs John Newton & Sons, engineers, Manchester; Mr. Giles, of Messrs. Mather & Pratt, electrical engineers, Manchester; Dr. Charles A. Burghardt, lecturer in mineralogy at Owens College.