以二氧化氯為前氧化劑作為垃圾掩埋場滲出液混凝處理之可行性探討

Feasibility Study of ClO2 pretreatment coupled with Coagulation-Flocculation process on Landfill Leachate Treatment

張忠吉(Chung-Chi Chang)

指導教授 ： 羅煌木

朝陽科技大學/理工學院/環境工程與管理系/碩士(2009年)

摘要

摘要
垃圾掩埋場滲出液成分複雜，其化學需氧量(COD)、生化需氧量(BOD)、懸浮固體物(SS)、色度、氨氮與磷酸鹽含量高，且含微量有機物如多環芳香烴碳氫化合物、壬基酚、雙酚A與金屬等。因此，滲出液的處理需要較高級的物理、化學與生物處理程序等，以確保放流水排放符合國家標準, 以降低其對人體健康與生態環境所造成的風險。本研究利用瓶杯試驗(Jar test)，探討以二氧化氯為前處理(設定六組不同的添加量0、10、50、100、200、500 mg l-1, 以探討其最佳添加量)，再配合硫酸鋁、多元氯化鋁(PAC)、氯化鐵為混凝劑(設定六組不同的添加量0、500、1000、2000、3000、5000 mg l-1，以探討其最佳添加量)，最後再調整滲出液pH值，分別設定為1、3、5、7、9與11(以探討其最佳pH)，以獲得掩埋場滲出液最佳處理效能參數組合。每一階段試驗以100 ml滲出液樣品，經添加攪拌混凝及靜置之後採集水樣上澄液進行各項水質參數分析，實驗參數分析包括COD、SS、色度、金屬等。實驗結果顯示，硫酸鋁、多元氯化鋁(PAC)、氯化鐵之COD去除率分別為36.7、26.3與27.8%，若以二氧化氯前處理，其COD去除率可提昇為47.9、40.4與43.9%。同樣實驗，SS去除率分別為76.2、76.8與79.4%，可提升至79.7、80.7與86.1%。而色度去除率分別為71、62.7與59.7%，可提升至97.1、93.7與90.9%。顯示以二氧化氯前處理，再以硫酸鋁、多元氯化鋁(PAC)、氯化鐵混凝處理，其COD與色度去除率可提昇11.2-31.2%，然SS去除率僅可提昇3.5-6.7%。金屬去除率則介於~0.4-100%不等。研究結果顯示，混凝劑如硫酸鋁、多元氯化鋁(PAC)、氯化鐵搭配二氧化氯前處理，可提昇掩埋場滲出液COD、色度與金屬之去除率。

關鍵字

色度 ； 金屬 ； 混凝劑 ； 瓶杯試驗 ； 化學需氧量 ； 二氧化氯 ； 滲出液

並列摘要

Abstract

Landfill leachate contains complicated constituents. Therefore, chemical oxygen demand (COD), biochemical oxygen demand (BOD), suspended solid (SS), color, NH4-N, PO43- in leachate are normally found at a higher values compared to other wastewater effluents. In addition, leachate contains micro organics such as polyaromatic hydrocarbons, nonylphenol, bisphenol A and metals. Therefore, landfill leachate needs advanced treatment such as physical, chemical, and biological process treatment to meet the national effluent standard and reduce the human health and environmental risks. This study used jar test to investigate the function of ClO2 as a pretreatment agent following by the coagulation and flocculation process to reduce the leachate concentration. Optimization tests were conducted by using ClO2 in the range of 0, 10, 50, 100, 200 and 500 mg l-1 and Al2(SO4)3, PAC and FeCl3 in the range of 0, 500, 1000, 2000, 3000 and 5000 mg l-1 respectively. In addition, pHs were set at 1, 3, 5, 7, 9 and 11 to obtain the optimal removal efficiency. At each stage of experiment, 100 ml of leachate was added with designated amounts of ClO2 and coagulants, then settled and filtered for COD, SS, color, and metals analysis. Results showed that COD removal efficiency by Al2(SO4)3, PAC and FeCl3 was found to be 36.7, 26.3 and 27.8% respectively. COD removal efficiency could be improved to be 47.9, 40.4 and 43.9% respectively if pretreated with ClO2. Similarly, SS removal efficiency treated by Al2(SO4)3, PAC and FeCl3 could be improved from 76.2, 76.8 and 79.4% to 71, 62.7 and 59.7% respectively. Results also indicated that pretreatment with ClO2 following by coagulation and flocculation of Al2(SO4)3, PAC and FeCl3 could enhance the COD and color removal efficiency about 11.2-31.2%. However, SS removal efficiency could only be found to be 3.5-6.7% and metals removal efficiency was found to be in the range of ~0.4-100%. From the results, it was shown that removal efficiency of COD, color and metals in landfill leachate could be improved when pretreated with ClO2 following by coagulation and flocculation of Al2(SO4)3, PAC and FeCl3.

並列關鍵字

Color ； COD ； Landfill leachate ； ClO2 ； Coagulants ； Jar test ； Metals

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