Treatment of groundwater for industrial uses
1980
Chonnamark Jamawatr
The dual objectives of the research were, firstly, to investigate the treatment of water containing iron alone and water containing both iron and manganese by Contact Filtration and, secondly, to reduce the alkalinity and hardness in water by Ion-Exchange. Three filtration rates (7.5 m3/m2-hr, 10 m3/m2-hr, and 12.5 m3/m2-hr) were used and, at the iron range of 1 to 5 mg/1, it was found that a filtration rate of 7.5 m3/m2-hr yielded the best compromise between the length of filter run and satisfactory effluent quality. The lower the flow rate, the higher was the efficiency of iron removal due to the greater contact time between the water and the sand bed. A mathematical model of the filter performance may be written as: Pc (11.41 - 3.88ti) - (1.47 - 0.37ti)C. - (0.19 - 0.44ti)F. A regression analysis made for the flow rate of 7.5 m3/m2-hr for water containing iron alone and water containing both iron and manganese showed that iron removal efficiency was higher in the latter case due to the oxidation of manganese to manganese dioxide in the filter. Studies on the exchange capacity of an exhausted resin in the sodium cycle indicated that an increase in the flow rate of raw water up to as high as 5 gpm/cu ft does not affect the exchange capacity. In this case, a 60 minutes regenerant contact time with a brine concentration of 12% should be provided. Similar studies in the hydrogen - cycle indicated that the exchange capacity increases with an increase in the sodium content of the influent water and decreases with an increase in total solids content of the influent water. In this case, a 5% concentration of hydrochloric acid with 60 minutes regenerant contact time should be used
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