Shogo Taniguchi

Even though O3/H2O2 based AOP has been proven to be an effective polishing treatment for sewage effluent, some of organic compounds were still found after treatment as the TOC value of treated sample was around 1 mg/L. In pursue of identifying these remaining substances, High Performance HPSEC-OCD was used to determine range of AMW of the remaining substances. In this study, four HPSEC-OCD results were observed and compared: (a) sewage effluent before AOP, (b) after ozone only treatment, (c) after ozonation with hydrogen peroxide addition in the beginning, (d) after ozonation with hydrogen peroxide continuously added. HPSEC-OCD chromatograms show that biopolymer in AMW range of 30,000 Da and LMW neutrals in AMW range of 500 Da were removed in all cases. However, humic substances and building blocks in AMW range of 2,700 and 2,000 Da are only removed in presence of hydrogen peroxide. LMW acids in which has AMW range of 1,100-1,200 Da were found irremovable. Furthermore, concentration in this AMW range increased after all treatment. The increase was hypothesized to be by-products of AOP reactions with larger molecules.

本研究は、回分式実験によりオゾンと4種の人工甘味料の反応量論について検討した。初期人工甘味料濃度を0.2 mmol/L、オゾン水濃度を0.0015〜0.0096 mmol/Lとして2分間反応させた。スクラロースについてはほとんど分解せず、オゾンの減少も少なかったことからほとんど反応が起こっていないと考えられた。サッカリン二水和物、アスパルテーム、アセスルファムカリウムは、オゾン1 molに対して、それぞれ0.92 mol、ア0.67 mol、1.1 mol分解することが確認できた。

A basic experiment was conducted using a batch type experimental device for confirmation of artificial sweetener decomposition amount with respect to ozone consumption. The artificial sweeteners used in the experiment was saccharin sodium dihydrate. Ozone water with an actual measurement value of 7.8 mg/L was gradually mixed with ultrapure water to make 50 mL, it injected into 100 mL of artificial sweetener 0.1 mmol/L. The experiment time was 2 minutes. As a result of the experiment, saccharin sodium dihydrate was decomposed by 0.5 mol with respect to 1 mol of ozone.

An O3 oxidation process and an O3/H2O2 advanced oxidation process were experimentally examined to decompose artificial sweeteners, which have the tendency to accumulate in ambient water. The artificial sweeteners examined in this experiment were saccharin sodium dihydrate, sucralose, aspartame, and acesulfame K. Decomposition of these sweeteners was achieved via both an O3 oxidation process and an O3/H2O2 advanced oxidation process. However, our results showed that organic byproducts were formed using both the processes.

As a follow up to our previously reported work, an advanced oxidation process involving O3/H2O2 was examined for decomposing organic matter in the effluent obtained from a final sedimentation tank, which was a part of the biological treatment process for sewage. The experiment was conducted using three addition methods of H2O2, which were addition at the beginning once, two-steps addition and continuance addition. The rate of decomposition was evaluated by calculating the rates of TOC decomposition, O3 consumption and H2O2 consumption. In case of this study, the continuance addition method decreased to 3.0 mgC/L, it was the lowest in the other methods.