Full Description

Alternative preoxidants such as ozone are being given serious consideration for reducing organic halide formation. The ability of ozone to remove trihalomethane (THM) precursors while improving turbidity removal has generated interest in the preozonation - alum coagulation treatment scheme. Alum coagulation removed all precursors tested (THM, total organic halides (TOX), trichloroacetic acid (TCAA), dichloroacetic acid (DCAA), dichloroacetonitrile (DCAN), and 1,1,1-trichloroacetone) to a significant extent. Ozonation at pH 7 with typical water treatment dosages and bicarbonate levels removed THM, TOX, TCAA, and DCAN precursors. Ozonation at 0.3 and 1.2 mg O3/mg C, at natural bicarbonate levels and pH 7, hindered the alum coagulation of organic precursors and the coagulation of TOC and UV-absorbing substances. Diminished overall removal as a result of preozonation was seen both with an aquatic fulvic acid solution and a moderately colored raw drinking water. Includes 33 references, table, figures.

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Edition: Vol. 76 - No. 4 Published: 04/01/1984 Number of Pages: 7File Size: 1 file , 1.8 MB