本研究以木質素試劑與家庭一級出流水為對象有機物，研究目的為(1)探討三價鐵混凝、Fenton及Fenton-like程序去除色度與溶解性有機物(DOC)之效果，(2)檢討Fenton及Fenton-like程序氧化與混凝去除DOC之機制。實驗用木質素廢水水樣DOC與色度分別為107.4 mg/L 與365單位；家庭一級出流水DOC為12.6 mg/L。所有實驗採瓶杯試驗，以pH、鐵鹽種類(亞鐵及三價鐵)與加藥量、過氧化氫加藥量為操作變數。以超過濾膜(UF)分離DOC分子量檢討各程序DOC分子量分佈變化，高中低分子量劃分分別為大於10k、1~10 k、1k Da。 木質素處理實驗結果顯示，三價鐵混凝處理木質素之最佳pH範圍為pH 3~5，於最適三價鐵加藥量50 mg/L，色度與DOC去除率皆可分達90 %以上。木質素為高分子有機物，高分子量(10 K Da以上)DOC佔75%，混凝去除以高分子量為主，殘留DOC以低分子量為主(1 K Da以下)，佔75%。Fenton/Fenton-like程序於pH 4，色度與DOC去除率皆可分達80 %以上，且殘留DOC之90%以上以低分子量為主。但由溶出實驗結果顯示DOC去除機制以混凝為主約佔96%，氧化則約佔4%，顯示氫氣自由基無法礦化去除DOC。 家庭一級出流水處理實驗結果顯示，三價鐵混凝處理家庭一級出流水的最佳pH範圍亦為3~5， DOC去除率可達約75%。Fenton/Fenton-like程序DOC去除率約80%。家庭一級出流水DOC以中、低分子量為主(10 K Da以下)，約佔67.5%，高分子量(10 K Da以下)佔28.6%，由溶出實驗結果顯示兩者DOC去除機制皆以氧化為主約佔90%，與前述木質素以混凝為主之結果相異，推測其原因乃家庭一級出流水DOC以以中、低分子量為主，可被氫氣自由基礦化以去除DOC所致。 This research evaluates the efficiency of three individual processes (coagulation, Fenton and Fenton-like) to remove organics from wastewater. The objectives to this research are 1).evaluating the removal efficiency of color and dissolved organic carbon (DOC) by ferric coagulation, Fenton and Fenton-like processes and 2).discussing the effects of oxidation and coagulation mechanisms on DOC removal by either Fenton or Fenton-like process. The tested organic wastewater is either prepared from lignin (DOC = 107.4 mg/L, 365 ADMI color unit) or domestic primary effluent (DOC = 12.6 mg/L) and all the experiments were conducted by the Jar test. The experimental variables include pH, dosage of iron salt (ferric and ferrous) and hydrogen peroxide (H2O2). The size of organics in wastewater is determined by the methods of ultra-filtration (UF) and classified from large to small on > 10k, 1~10k and < 1k Dalton (Da). The results show that the optimal pH and the dosage of ferric salts on color and DOC removal (> 90 %) are 3~5 and 50 mg/L respectively for the artificial lignin solution tests. The lignin is a high molecular weight DOC with 75 % of large size molecular (> 10 kDa) while reduced to 75% of small size molecular (<1 kDa) in the solution after coagulation process. The color and DOC removal efficiency are up to 80 % (at pH 4) on Fenton and Fenton-like processes with greater than 90% of small size molecular (<1 kDa) in the residual solution. The further test shows that 96% of the DOC is removed by coagulation mechanism and only 4 % is by oxidation. In other words, the hydroxyl radical (OH‧) did not play the major role in DOC removal on Fenton and Fenton-like processes. As of the domestic primary effluent, the optimum pH is 3 to 5 in ferric coagulation test and the DOC removal efficiency is 75 %. The DOC removal efficiency is around 80 % in either Fenton or Fenton-like processes. The smaller molecular weight (< 10 kDa) of organics composed in domestic wastewater is 67.5 % while larger molecular weight (>10 kDa) organics is 28.6 %. Furthermore, 90% of the removed DOC of domestic wastewater is by oxidation mechanism in both Fenton and Fenton-like processes which is different from lignin samples primary on coagulation mechanism. The results may arise from the mechanism which the hydroxyl radical is easier to breakdown smaller size of the organic molecular which dominates in domestic wastewater comparing to larger size in lignin samples.
