50 



The amounts of sodium carbonate (soda ash, Na^Cog) and 

 hme (CaO) needed to treat the waters were calculated, using 

 factors as follows : 



!\Iagnesium chloride, MgClo to Soda ash, Na.COs. . 1 . 1130 

 Alagnesium sulphate, AlgSO^ to Soda ash, NeoCO.... .8811 



Calcium sulphate, CaSO^ to Soda ash, NaXO,^ 7792 



Sodium carbonate, NaoCOg to Lime, CaO 5287 



Magnesium chloride, MgCL to Lime, CaO 5889 



Magnesium sulphate, MgSO^ to Lime, CaO 4659 



Magnesium carbonate, MgCog to Lime, CaO 1 . 3300 



Calcium carbonate, CaCOg "to Lime, CaO 5600 



Parts per million to grains per gallon 05833 



Parts per million to pounds per thousand gallons 008345 



The amounts are calculated on the basis of pure soda ash 

 and pure lime, and no account is taken of the residual carbonate 

 of calcium and magnesium which can not be removed. Practice 

 would probably show that the approximate cost is therefore a 

 trifle high. The amount of soda ash present has been included 

 in the calculation of the lime needed for the waters of Class 

 L This is according to the laboratory experiments of Bartow 

 and Lindgren.* 



The results are given in parts per million, grains per gallon 

 and pounds per thousand gallons. This will make it con- 

 venient for treatment on a large or small scale. Those desir- 

 ing to soften water for use in the household, where the whole 

 supply is not softened, may soften from a few gallons up by 

 adding the calculated amount. We have tried the experiment 

 with the water at the University of Illinois on a laboratory 

 scale, using 30 liters of water; and on a household scale, using 

 1,000 gallons of water. The Champaign and Urbana water 

 supplies are in this way softened so that the soap-consuming 

 capacity is very much decreased and so that the possibility of 

 staining white goods from the iron present is entirely eliminated, 

 and there is no danger of clogging the water-backs in the ranges. 



vShould plans be made to' soften the water furnished from 



•Bartow an'i Linflgren, Proceedings of the Am. Water Works Assn. Vol. 27, 

 page 505, (1907.) 



Univ. of Illinois Rulletin, State Water Survey Series, No. 6. 



