~Table 23--Relative Cost of Filtering at Different Rates.~ ======================+=================================================== |Nominal rate, in millions of gallons per acre daily: +------------+------------+------------+------------ | 3 | 5 | 10 | 20 ----------------------+------------+------------+------------+------------ Percentage which | | | | average yield is of | | | | nominal rate..........| 85 | 80 | 75 | 65 ----------------------+------------+------------+------------+------------ Average output per | | | | acre, in millions of | | | | gallons per day.......| 2.55 | 4.00 | 7.5 | 13.0 ----------------------+------------+------------+------------+------------ Cost of that part of | | | | filters per acre | | | | dependent on rate.....| $12,000 | $20,000 | $40,000 | $80,000 ----------------------+------------+------------+------------+------------ Cost of that part of | | | | filters per acre not | | | | dependent on rate.....| 50,000 | 50,000 | 50,000 | 50,000 ----------------------+------------+------------+------------+------------ Total cost of filters | | | | per acre..............| 60,000 | 70,000 | 90,000 | 130,000 ----------------------+------------+------------+------------+------------ Cost per million | | | | gallons of capacity...| 20,600 | 14,000 | 9,000 | 6,500 ----------------------+------------+------------+------------+------------ Cost per million | | | | gallons of average | | | | daily output..........| 24,400 | 17,500 | 12,000 | 10,000 ----------------------+------------+------------+------------+------------ Capital charges and | | | | depreciation at 6% on | | | | cost per million | | | | gallons...............| 4.00 | 2.87 | 1.97 | 1.64 ----------------------+------------+------------+------------+------------ Operating expenses, | | | | the same at all | | | | rates.................| 1.00 | 1.00 | 1.00 | 1.00 ----------------------+------------+------------+------------+------------ Total cost of | | | |