1890-91. J A CONSIDERATION OF SEWERAGE SCHEMES. 149 



admit of part of the contents of a full tank being discharged into an 

 empty one for the purpose of flushing out deposits. Ample provision is 

 made for ventilation, there being 27 fresh air inlets in the three tanks, 

 while the fumes are collected by a flue 4 feet high and 2)^ feet wide 

 and conveyed to the under side of a coke furnace, and passed into a 

 chimney shaft about lOO feet high. 



The rapid discharge of the whole of the impounded sewage is an 

 essential feature of the scheme ; the outlets are sufficiently large to 

 admit of all the sewage being discharged into the outfalls and thence 

 into the sea, within a period of one hour. The mouths of the outlet- 

 pipes lie just below low water mark. Before definitely deciding upon 

 the point of discharge of the sewage, experiments were caused to be 

 made to ascertain the course that would be taken by the sewage under 

 the diverse conditions prevailing. It was found that the floats were 

 carried many miles out to sea when placed in the tide-way soon after 

 high-water, and the works were designed so as to admit of an exceed- 

 ingly rapid discharge of the sewage in order to take full advantage of 

 this circumstance. On the arrival of the period when it is desirable to 

 allow the sewage to be discharged into the sea, a small penstock is 

 opened, the escaping sewage operates a turbine, which in its turn sets in 

 motion the machinery by means of which the large penstocks are 

 opened ; thus one man can readily open these ponderous appliances, 

 and attend to the tanks as well. 



The pumping station and rising main cost i^2 5,000, and the tanks and 

 outlall works ;^45,ooo. The annual working expenses at both pumping 

 station and tanks amount to £2,joo per annum. 



This brings me to my second head. 



I have given the sewage disposal works of Portsmouth considerable 

 space as they afford a good example of a free outfall into the sea or 

 large body of water, and I have always strongly recommended that 

 method of sewage disposal for the city of Toronto. Indeed, it was a 

 consideration of the immense advantage to sewage discharge afforded 

 by tidal waters which led me to devise a scheme that would secure to 

 Toronto the advantage of a tide, though on the tideless waters of Lake 

 Ontario, and those of you who are familiar with my scheme will 

 recognize how fully these have been secured. You will observe that by 

 means of a high-level sewer along, say, Gerrard street, between Yonge 

 and Parliament streets, intercepting all the sewage north of that line and 

 conveying it into a tank situated down near Front street, we secure the 

 benefit of a tide, not ten or twelve feet high, but 32 feet high, or more 

 \{ we require it. Next, we can have it just when we want it and have 



