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A kinetic model of the ozone/hydrogen-peroxide process for treatment of groundwater

Thesis/Dissertation ·
OSTI ID:6747533

The objective of this work is to evaluate the O{sub 3}-H{sub 2}O{sub 2} process in laboratory scale experiments and to subsequently develop a generic mathematical model of the O{sub 3}-H{sub 2}O{sub 2} process for the treatment of ground water containing various organic contaminants, especially halogenated hydrocarbons. The process model was evaluated for the case of a stirred, semi-batch reactor in three regions determined by the relative feed rate of ozone and peroxide. In region I, where peroxide feed rate is less than the stoichiometric optimum, the rate of reaction is limited by the hydrogen peroxide feed rate. In region II, the ratio of ozone and peroxide feed rate is near the stoichiometric optimum. In region III, the reaction rate is limited by the rate of ozone transfer into the liquid phase, i.e., the higher the ozone content in the feed gas, the larger the reaction rate. The process model suggests that too large a dose of peroxide will have an inhibitive effect on the oxidation rate. The mass transfer/reaction rate model can be used as a tool for estimating k{sub M,OH}, the rate constant for the reaction of organic substrate with the OH radical. The estimated values of k{sub PCE,OH} (2.1 {times} 10{sup 9} M{sup {minus}1} s{sup {minus}1}) and k{sub TCE,OH} (3.5 {times} 10{sup 9} M{sup {minus}1} s{sup {minus}1}) for tetra- and trichloro-ethylene respectively, are in good agreement with the literature values. The process model can also be utilized to rationalize the effect of OH scavengers in ground waters. For typical ground waters in Southern California, the model suggests that removal of bicarbonate by softening will enhance the rate of oxidation of organic micropollutants.

Research Organization:
California Univ., Los Angeles, CA (USA)
OSTI ID:
6747533
Country of Publication:
United States
Language:
English