70 A Solution of the Sewage Problem. [January, 



were expected. The usual take of sewage was at the rate 

 of 4800 gallons per hour, but on some occasions the working 

 was pushed until the sewage was flowing at the rate of 

 10,000 gallons per hour. At this rate the precipitation 

 and the settlement proceeded without difficulty, whilst the 

 effluent continued to flow away without deterioration. Let 

 us take the data of these works as the basis upon which to 

 draw up a profit and loss account of a day's work. 



Ten thousand gallons of sewage per hour amount to 

 100,000 gallons per day of 10 hours. 



For this are required the following chemicals : — 



Kilos. Kilos. Frs. 



Animal Charcoal . . 250 at 170 frs. per 1000 = 42*5 



Vegetable Charcoal . 500 ,, 50 ,, ,, = 25*0 



Clay 600 „ 6 „ „ = 3-6 



Lime and Blood . . 70 ,, 12 ,, ,, = o*8 



Sulphate of Alumina 162 ,, 130 ,, ,, = 21*0 



Total used . . 1582 ..... costing 92*9 



The labour consisted of — 



Four men, wages per day . . . 13*75 f rs - 



One superintendent io'oo ,, 



Add one extra man 4*00 ,, 



2775 „ 

 The steam-engine burnt less than half a ton of coals a 

 week. This with a few sundries, such as oil, &c, amounted 

 to about 36 frs. per week. 



The mud was simply pumped from the bottom of the tank 

 into an open-air stank, where it rapidly dried under the 

 influence of the sun and wind, assisted by the porosity of 

 the soil. The drying therefore cost nothing. 



Owing to the excessive dilution of the Paris sewage from 

 rainfall, from the copious street washings, and from the fac\ 

 that most of the night-soil is carted away to La Villette, the 

 yield of dry " native guano " was very poor, not more than 

 114 parts being obtained for every 100 parts of A B C ma- 

 terials added, as against 163 yielded under similar circum- 

 stances from London sewage. As 1582 kilos, of A B C ma- 

 terials were added, the '* native guano" would be 1808 kilos. 

 The total expenses were — 



Chemicals 92*90 frs. 



Labour 2775 „ 



Coal and Sundries 6*oo „ 



126*65 „ 



