191'J] KUKAL ENGINEEEING. 89 



It is pointed out that the disease is somewhat prevalent here and there 

 among poultry flocks in the State of Iowa. Of 255 fowls examined at the 

 pathological laboratory of the Iowa State College from July 1, 1912, to Sep- 

 tember 11, 1915, tuberculosis was the cause of sickness or death in 43. Of 227 

 fowls similarly examined between September 11, 1915, and June 1, 1918, 83 

 were affected with tuberculosis. 



KURAL ENGINEERING. 



Softening hard water with permutit, R. Hulbert {North Dakota Sta. Spec. 

 Bui., 5 {1919), No. 9, pp. 193-208, figs. 3).— Continuing the series previously 

 noted (E. S. R., 40, p. 588) tests of a small-sized permutit water softener on 

 water from the city supply of Fargo, N. Dak., are reported. 



" The plant consists of a hollow steel cylindrical shell, 9 in. in diameter by 

 5 ft. in height. The cylinder is closed at the top with removable, water-tight 

 head, to operate under pressure. For these tests the softener was charged with 

 40 lbs. of new permutit mineral, resting on a 5-in. layer of coarse gravel. This 

 charge is supported on a perforated steel plate some 6 in. above the bottom of 

 -the tank. Above the bed of pernmtit is placed an upper screen-plate holding a 

 5-in. layer of coarse, screened, washed marb'e, the purpose of which is to re- 

 move carbon dioxid from the raw water before it passes through the permutit. 

 Supported on brackets at the right and on a level with the top of the cylinder 

 is the brine tank holding about 10 gal., in which is prepared the salt solution 

 for regenerating the permutit. A water meter is placed in the hard water intake 

 pipe for controlling the rate of softening and backwashing, and to indicate the 

 total volume of water passed through the plant in either of these opera- 

 tions. . . . 



" The zero water capacity of the permutit softener operated in these tests was 

 five times its rated capacity, as stated by the manufacturers. This very con- 

 siderable underrating, if carried out in commercial practice, should guaranty 

 that this type of softener would always furnish at least its rated capacity of 

 completely softened water even under adverse operating conditions, which in 

 practice might result from (1) abnormal increases in the hardness of the raw 

 water, (2) incomplete regeneration, (3) allowing the softener to exceed its 

 specified maximum rate, or to exceed its rated capacity between regenerations 

 through careless operation, and (4) any possible depreciation in the quantity 

 of zeolite over a number of years. 



" The permutit content of the softener is only about one-third completely 

 exhausted when the filter has delivered its full capacity of zero water. Re- 

 membering that its full capacity in these tests was five times more than its 

 rated capacity, it follows that in normal operation the zeolite is only slightly 

 exhausted between regenerations. Permutit may be fully regenerated even 

 from complete exhaustion. This requires, however, a disproportionately large 

 volume of brine with a much higher concentration of salt, and a longer period of 

 time than is feasible under practical operating conditions. A permutit installa- 

 tion will easily furnish double its rated capacity of zero water when operated 

 intermittently, and without exhausting the zeolite beyond the point where it 

 may be restored by a normal regeneration. 



" Under any operating conditions the cost of salt for regeneration will not 

 exceed 0.7 ct. per thousand gallons of soft water for each grain per gallon of 

 hardness removed. Fargo city water can be softened completely by permutit 

 at a total cost not exceeding 20 cts. per thousand gallons. This estimate in- 

 cludes all fixed and operating charges. The soap consuming power of Fargo 



