Mr. Paterson. It leaves a fair margin of profit.
Mr. Mignault. What do you mean by a fair margin of profit?
Mr. Paterson. A fair margin of profit, and to pay for the depreciation of the plant, the redemption of the plant, the money that is necessary to keep it up, the cost that the city has gone to, and leave interest on the money plus decrease of capital, plus profit, I should think $1 a ton profit on 100,000 people, after paying all this, would be quite a good thing.
Mr. Magrath. I suppose, as a matter of fact, this process is in the experimental stage, or do you consider it is now sufficiently established?
Mr. Paterson. It is sufficiently established, because the plant is paying. It went from the laboratory to a small plant at the rate of a ton a day, and now it has gone to a bigger one and a bigger one. We practically hope, and we are pretty sure, that we are going to take over the London sewage, which would be a very large plant.
Mr. Mignault. How much money has been invested in these plants?
Mr. Paterson. The one at Wimbledon is not a fair criterion, because it has been in operation for a long time, and it has gone through all the initial stages of a new process. Now, of course, it is in perfect order, and running smoothly, and giving good results, but it has come up from a smaller plant to a large degree, and there were lots of difficulties encountered which have been surmounted. I suppose it might be said to cost $300,000 now.
Mr. Gardner. And, in the light of your experience, what do you estimate you could duplicate that plant for?
Mr. Paterson. The same plant could be put in to-day easily for $40,000 or $50,000. Of course, in a new process we are continually putting in different things and trying different things, and also extracting things which we never dreamed of were in the material.
Mr. Dallyn. Is it not a fact that when the pressed sludge was first offered to the agricultural interests in England it was taken up and they paid a certain amount for it?