Nozomu Yasunaga

Efficient Decomposition of Trichloroethylene (TCE) in Groundwater by Ozone-Hydrogen Peroxide Treatment

It was verified that the ozone-hydrogen peroxide treatment (O3/H2O2) was very effective for decomposing trichloroethylene (TCE) in groundwater. The reaction efficiency of O3/H2O2 was 40% better than that of ozone treatment by using a diffuser type reactor and the optimum operating conditions were also revealed by laboratory-scale experiments and computer simulations. Taking these results into consideration, the 2-port ozone injection method using an ejector-type reactor was investigated to decompose TCE more rapidly and efficiently, and it was revealed that the ozone dose necessary for satisfying the Japanese water quality standard for drinking water (0.03mg/L) by the 2-port ozone injection method was 13% less than that by the conventional 1-port ozone injection method under the condition of the same amount of ozone injected. Also, the effectiveness of the 2-port injection method was proved by a sequential plant-scale experiment for about 40 days.

New Approach for Optimization of Ozone-Hydrogen Peroxide Water Treatment

A new radical reaction model for the ozone-hydrogen peroxide treatment, which was much simpler than current models such as SBH and TFG, has been developed by computer simulation in order to investigate a new reactor for this treatment process. It was revealed that the simulation results by using this new developed model were in good agreement with the experimental results in terms of the variation in the concentration of ozone in both gas and liquid phase, hydrogen peroxide and TOC, indicating the appropriateness of this new model. Thus, it was considered that this new model was very convenient for analysis of radical reactions because of its simplicity.