Full Description

Mechanisms for the removal of humic substances from water by coagulation with aluminum salts were studied by means of conventional jar test procedures. Independent variables were the type and concentration of humic substance, the type and concentration of aluminum coagulant, and pH. Removal of humic substances was determined by measuring total organic carbon or by direct ultraviolet spectroscopy. Under some experimental conditions the humic substances were directly precipitated by soluble aluminum species; under other conditions, they were removed by adsorption on Al(OH)3(s). The choice of coagulant for the removal of fulvic acid will depend on the fulvic acid type and concentration, pH and pH buffering, certain other components of the water (e.g., sulfate), the volume of sludge generated, and the availability and cost of the coagulants. It is apparent that aluminum is quite versatile as a coagulant, and even more diverse coagulants containing aluminum are likely to emerge in the future. Polyaluminum chloride, an unconventional coagulant in the United States, is a promising alternative to alum for removing humic substances from some water supplies. Includes 76 references, tables, figures.

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Edition: Vol. 76 - No. 4 Published: 04/01/1984 Number of Pages: 10 File Size: 1 file , 2.7 MB