WATER FILTRATION. XLIII. 



water to be dealt with. The following information is 

 obtained from the work on "Public Water Supplies," by 

 Turneaure and Russell, 1901, from which it will be seen that 

 the cost of construction of filter, covered and uncovered, 

 exclusive of subsiding reserves, is somewhat high. Large 

 beds and extensive works will cost less per unit area than 

 smaller ones, other things being equal. At Berlin, covered 

 filters of about 0*6 acre each have cost about £14,600 per 

 acre. At Zurich, filters of one-sixth acre each, cost for the 

 masonry and filtering materials only, about £10,000 per 

 acre for open and £15,000 for closed beds. Engineer 

 Lindley estimates as a reasonable cost in Europe for care- 

 fully designed filters, about £14,200 for covered and £9,400 

 for open filters. 



Taking the average quantity filtered by the London com- 

 panies at \\ million gallons per acre per day as a basis, the 

 cost of construction of filters works out at an average of 

 £6,700 per million for uncovered and £10,000 per million 

 gallons for covered filters, exclusive of subsiding and clear 

 water reservoirs. 



At Ashland, Wis., U.S.A., three covered filters of one-sixth 

 acre each, cost £8,370, but the engineer estimated that 

 under normal conditions the cost there would be about 

 £7,300 for beds of ^-acre each, which is equal to about 

 £14,600 per acre. At Ploughkeepsie, a single open bed of 

 29,640 square feet cost £6,021, equal to £8,750 per acre. 

 At Berwyn, Pa., three open beds of 7,500 square feet, each 

 cost £3,862, equal to £7,500 per acre. The best figures at 

 hand for the cost of filters on a large scale are those for 

 the Albany plant. The cost for eight covered filters of an 

 area of 0*7 acre each, was £9,500 per acre, not including 

 land and engineering; the latter item, figured pro rata 

 from the total cost, would add about £520 per acre. The 

 covers were estimated to have added about £2,700 per acre 



