高濃度COD之廢水，若直接用生物處理法加以處理，其效果往往不盡理想。基於如此，以電-芬頓處理程序來處理高濃度COD廢水，已備受各產業界矚目。其主要原理是利用電解氧化還原的方法，將Fenton反應後所產生的鐵離子，在陰極上還原成亞鐵離子，再繼續與過氧化氫反應，而達到連續循環性地破壞污染物之功效，並且在系統陽極上，可因電解氧化反應而直接氧化有機污染物。因此，電-芬頓法是一種能同時產生兩種破壞污染物的反應，進而使污染物礦化，達到降低COD濃度之目的。本研究乃採電－芬頓法處理酚醛樹脂廢水，並且以改變實驗條件中的亞鐵離子濃度、過氧化氫濃度、通電電流大小及加藥方式，來探討各條件下，系統對COD去除效果的影響。
結果發現，以電-芬頓法可處理COD濃度高達18000mg/L之酚醛廢水，在實驗起始條件為亞鐵離子濃度1004mg/L、過氧化氫濃度39550mg/L、電流2安培通電2小時及調整處理液pH至2.0的情況下，其最後COD去除率可達85%以上。此外，如果在相同條件下，增加過氧化氫的加藥量至59325mg/L時，則COD去除率可達95%以上。 Removal of COD from wastewaters with high COD by biological processes generally cannot meet the discharge standard. Therefore, applying AOPs, such as electro-Fenton process, in the treatment of high concentration and toxic wastewater has been got much more attention by the industries. In electro-Fenton process, ferrous ions are regenerated from ferric ions on the cathode, which increases the production efficiency of hydroxyl radicals. On the anode, oxidation reaction occurs and organics can be oxidized. In this study, electro-Fenton process was applied to treat the wastewater coming from the phenol formaldehyde resin industry. Experimental parameters, namely ferrous concentration, hydrogen peroxide concentration, current density and addition mode of reagents, were selected to study their effect on the removal of COD from this kind of wastewater.
Results show that electro-Fenton technology can be used to treat the wastewater containing high concentration of phenol and formaldehyde. When the COD of the wastewater was about 18000 mg/l, the removal ratio can be above 85% under the experimental conditions of Fe2+=1004 mg/l, H2O2=39550 mg/l, current=2 A and pH=2.0. Furthermore, the removal ratio can reach 95% with increasing the hydrogen peroxide concentration to 59325 mg/l.
