Mr. Powell. You speak of the purification of the effluent up to a certain standard. Would you have that standard fixed without regard to whether the effluent is flowing into a small or large stream? Can you fix it absolutely, without regard to the size of the stream, or the quantity of water that was in the stream to dilute it?
Mr. Dallyn. The sedimentation part of it should be fixed absolutely. I do not see any difficulty in doing that. There appears to be no practical or structural difficulty in requiring a certain percentage removal, or a given number of parts per million, of residual suspended matter. As to the number of bacteria to be removed, I think that could be more flexible, depending entirely upon the use the stream was to be put to, whether as a channel of commerce, or used largely as a pleasure resort, or whether it had no particular value in either of those spheres. We have in our Province a great deal of trouble by reason of townships complaining against the discharge or raw sewage, or even treated sewage, from some of the municipalities, saying it affects cattle. It is a disputed matter, but they certainly have the law on their side, and can compel the municipalities to purify to a much greater extent than some of you might think advisable.
Mr. Powell. What is the growing consensus of opinion in respect of the purification of the effluent before allowing it to go into the stream?
Mr. Dallyn. Well, there seem to be two schools—the school of cranks, asking a high standard, and the conservation school, who want to use our natural resources to the utmost extent, and who sometimes overlook some of the changing factors which are not usually taken into consideration. I belong to the school of cranks, as I told you before, and I would like to see some better standard adopted than might immediately appear necessary, as in education we require to learn more than our vocation appears to demand when measured by practical methods of the conservation school.
Mr. Powell. Great Britain seems to head the movement in purification of streams.
Mr. Dallyn. They have much smaller streams.
Mr. Powell. It is a different problem, on account of the different quantity of water in the streams.
Mr. Dallyn. They lack the water-supply problem, and have to treat the sewage from the æsthetic point of view more than any other. I have in mind the ability of the stream to take up the putrescible matter, without giving out odors. In places where several centers must utilize the same stream there must needs be a more intense purification than where one center only enters it. With your problem the purification as to bacterial removal will have to be some function of the population in the congested centers. In other points, like Sarnia and Port Huron, the bacterial degree of pollution is not very heavy, not reaching the 500 standard Prof. Phelps recommends as being considered a contravention of the treaty, and the function of population does not amount to very much, so here you would have to treat it very much better than you apparently need. As a rule, when you use chemicals to disinfect sewage, you get no action at all until you remove about 60 per cent. You get a 60 per cent removal or you get nothing. It seems to be inert; and then you have to increase your quantities till you get up to 100 per cent removal, the last 10 per cent taking almost half as much again as the 90 per cent.
Mr. Powell. Your idea is that under no circumstances should there be any discharge into the large or small stream without purification to the extent of sedimentation?
Mr. Dallyn. I believe our civilization has reached a point now where, as far as self-respect goes, we are required to separate the gross solids from the liquid matter before discharging them into any stream.