Control of Trihalomethane Precursors in Drinking Water: Granular Activated Carbon With and Without Preozonation

Abstract

In a pilot study that lasted 80 weeks, unozonated and ozonated waters were fed to granular activated carbon (GAC) columns to compare the removal of trihalomethane formation potential by GAC treatment with that by ozone‐GAC treatment. The results were comparable for these treatments.

Adsorption and Microbiological Mechanisms for Removal of Natural Organics in Granular Activated Carbon Columns

“…Indeed, after approximately week 35. no adsorptive removal i s predicted, yet the plant columns continue to remove TOC (20). The shaded portions of Figures 5-8 becomes increasingly significant.…”

“…That such a mechanism exists, and that i t i s biological, i s suggested by two types of evidence (7.19.20): (a) carbon dioxide production across the GAC columns which reaches a maximum rate in the period from week 2k to week 50 (20). and (b) modified plate count data on effluent and influent waters and the GAC surfaces.…”

“…In the present paper, the approach of Lee and coworkers is used to rationalize the performance of a GAC pilot plant described by Glaze et al (7,19,20 …”

Effect of Ozone Dosage for Removal of Model Compounds by Ozone/GAC Treatment

“…Some ozonation by-products may have adverse effects on the adsorption efficiency of activated carbon because of the increase of polarity and hydrophilicity (Glaze and Wallace, 1984). Typical by-products of dissolved organic matter (DOM) by ozonation include low molecular weight (MW) aliphatic aldehydes, hydrogen peroxides and organic peroxides, and mixed functional and saturated carboxylic acids (Glaze, 1986;Gracia et al, 1996;Weinberg and Glaze, 1997); also, ozonation by-products, i.e., aldehydes, increase with the increase of ozone dose and ozonation time (Glaze et al, 1989;Yamada and Somiya, 1989).…”

Kinetic rate constants for the formation of trihalomethanes in chlorinated ammonia containing ground water

“…Activated carbon has been using singly or coupled with other processes to remove humic precursors (Glaze and Wallace, 1984). The removal potential of ozonation, ultraviolet light, coagulation (Babcock and Singer, 1979;Thurrott and Duryea, 1983), direct filtration (Scheuch and Edzwald, 1981), and permanganate oxidation/ manganese dioxide absorption have been evaluated (Colquist et al, 1982).…”