Mr. Paterson. Yes.
Mr. Dallyn. The use of chemicals for precipitating in your sedimentation tanks would make it cost more.
Mr. Paterson. In certain cases they do not use a precipitant at all, but in other places they do. In places they use lime and alumina, and that is expensive: It does not affect the process at all if lime or any other agglomerant is not used, you still have the solids left. They are rather getting away from lime precipitation on account of its cost, but, on the other hand, where they have it for a fertilizer they are getting the value back that they paid for their lime to a very large degree, and possibly they are making a profit out of it. There is no doubt that lime does give more rapid precipitation, and it has its advantages, but it does not affect the solids for treatment or the by-products that you get from the solids.
Mr. Magrath. Do I understand that none of the important centers have yet taken this matter up?
Mr. Paterson. They have signified their intention to take it up. Glasgow and Sheffield are contemplating putting in a plant, and Derby and Leeds. The plants would have been built this year, but the condition in England now is that no municipality can lend money without the sanction of the treasury. The plans are drawn for Glasgow, Leeds, and Sheffield.
Mr. Tawney. Is this a patented process?
Mr. Paterson. In part; the distillation part is not patented.
Mr. Mignault. Did you tell us what profit is realized out of the disposal of the sludge?
Mr. Paterson. That could only be given in a general way, depending on the quantity which is treated. In London, which has 100,000 tons a year, you would naturally make a very large profit there in comparison to a city of 3,000 or 4,000 or 20,000 people.
Mr. Mignault. Take a city of 100,000 people.