Mr. Hatton. Yes; for instance, phosphoric acid is worth to-day 10 times as much as the quotations I have used in making my valuations.
Mr. Tawney. Have you any questions, Prof. Phelps?
Prof. Phelps. No.
Mr. Dallyn. Just one point that Mr. Mignault brought out. Comparing the results of your process with the Imhoff tank, Mr. Mignault rather concluded that the Imhoff tank could be used in the same location as your plant. Is it not true that the effluents from the two types of treatment compare as the two samples on the table, activated sludge effluent being clear, and that from the Imhoff tank turbid and discolored, similar to raw sewage?
Mr. Hatton. That is true. I answered that with the idea of nuisance to the adjacent neighbor.
Mr. Dallyn. What is your actual saving, as you actually contemplate placing interceptors, collecting the sewage, in the adoption of your method?
Mr. Hatton. We are saving about $2,000,000 in carrying out the subaqueous tunnel a mile and a half out to sea, as the original board of engineers suggested.
Mr. Powell. I understood you to give that as the esthetic feature?
Mr. Hatton. Yes; not only esthetic feature, but the purification feature; in other words, the local engineer has indicated that he would not permit, with his sanction, any sewage disposal plant which would deposit that much suspended matter in the harbor.
Mr. Mignault. The question I put to you was to ascertain, in case they decided to establish other treatment plants in order to avoid constructing sewers, whether your system had any advantage over the Imhoff-tank system?