Clarification of the Public Water Supply of Cincinnati. 3 5 



contact with a solid cylinder of Alum, coated on the sides with 

 wax, to prevent its too rapid solution, and the dissolved Alum 

 coagulates the suspended matter and causes it to combine in masses 

 that are retained in the pores of the filter. 



At intervals of about twenty-four hours the mass of sand and 

 coke is released, and the pressure under which the filter operates 

 causes it to rise with a boiling motion into the upper part of the 

 tank, where the friction of the sand in boiling separates the mud 

 deposited, and the force of the current carries it off through an 

 overflow. The cleansed filtering material is then permitted to fall 

 into the bottom of the tank and is ready for a second operation. 



Tabulated Tests of Water from the Hyatt Filters. 



Note. 



Samples 2 and 4 were collected immediately after putting in new 

 cylinders of Alum before the water had attained perfect clarifica 

 tion. 



Deductions. 



The Hyatt Filter in the four samples tested increased the hard- 

 ness of the water on an average 4.3 Metric Degrees. This aver- 

 age is probably somewhat lower than the rate at the time of the 

 experiments. (See note Alum.) It can be made to produce very 

 bright and sparkling water and if the Alum used is the minimum 

 necessary, this result may be reached without increasing the hard- 

 ness more than two or three Metric Degrees. 



The water required daily to wash the filter is e&timated at 100 

 gallons or about 3,000 gallons per month. The water passing 

 through the meter per month is 500,000 gallons. 5|{|goff=-oo6 

 or /„ per cent. The Alum used is about 5 pounds daily or about 

 300 pomids to clarify 1,000,000 gallons of water- 



