METHOD OF REFINING POLLUTED WATER

摘要

Water purifcn. comprises percolating the water downwards through a submerged, fixed bed of granular filtration material while introducing O2-contg. gas at an intermediate level in the bed. The flow rates for gas and water obey the equations: (Q1 and Q2 = flow rates of gas and water in cu.m./hr; epsilon = porosity of the bed material; alpha = max. fraction of the vol. which can be occupied by gas without affecting efficiency; S = area (m2) and h = height (m) of the bed; V = vertical component of mean velocity of rising gas bubbles; K1 = vol. of bed occupied by immobilised gas bubbles (cu.m); K2 = O2 concn. in the gas (kg/cu.m); K2 = O2 demand of 1 cu.m of carbon in 1 hr. under process conditions (kg/cu.m./hr); R = overall transfer yield (wt. O2 effectively dissolved divided by O2 injected); DO = O2 demand in kg per unit vol. of water treated). The process is for treating surface water etc. to make it drinkable, or for processing sewage and industrial wastes.