ABSTRACT
In this study, the merits of using H2O2/UV oxidation for reducing trihalomethane formation potential (THMFP), colour, and dissolved organic carbon (DOC) of smaller molecular humic acid were investigated, especially the energy consumption based on EEO. The results show that THMFP decreases by increasing oxidation time, H2O2 dose and UV intensity. The reaction constant in descending order is kColour>kDOC>kTHMFP. Furthermore, EEO shows three trends. First, it decreases as H2O2 dose increases. That is, by increasing the amount of H2O2 dose, the electrical energy efficiency becomes better. Second, EEO,9â W>EEO,13â W, implying that higher UV power would result in a higher electrical energy efficiency. Third, EEO,THMFP>EEO,DOC>EEO,colour. That is, the electric energy efficiency is the best for colour removal, second for DOC removal, and third for THMFP reduction. The operation costs for 90% removal of colour, DOC, and THMFP are from 0.31 to 0.69, from 0.78 to 1.72, and from 1.11 to 2.29â US$/m3, respectively. However, reducing THMs to Taiwan's drinking water standard of 80â µg/L needs only 0.25-0.60â US$/m3. Therefore, the condition with UV of 9â W, H2O2 of 50â mg/L, and oxidation time of 23â min can be applied for THMs reduction as the cost is the smallest of 0.25â US$/m3, even lower than current Taiwan's drinking water price of 0.3â US$/m3.