... 4.1ⅹ104∼1.5ⅹ107CFU/㎖. The above experimental results put together, seasonlessly, on the first day after backwashing, HPC increases and then gradually decreases; the longer days of operation, the higher ... carbon from 24 ones in the M water purification plant in Daegu; tried to find out the optimum condition by changing the time and method of seasonal backwash from October, 2001 to September, ... 1. The present condition of granular activated carbon contact basin facilities Division Conditions The charge amount and indexes of activated carbon 250m3(8mⅹ12.5mⅹ2.5m), 24 basins The...