Treatment of Polluted Raw Waters by Chemical Coagulation and Fenton's Process Combination

• Main Authors: Su, Yi-Cherng, 蘇怡成
• Other Authors: Kang Shyh-Fang
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/64763541141421242989

碩士 === 淡江大學 === 水資源及環境工程學系 === 84 === This study uses the combination of chemical coagulation and Fenton'sProcess to treat polluted raw waters. Because it is inefficient to usechemical coagulation to remove the low-molecular-weight organic compounds(e.g. pesticide, phenol) , and Fenton's reagent has dual functions ofpreoxidation and coagulation, we consider using conventional coagulation withFenton's reagent to remove the low-molecular- weight organic compounds. Thisstudy is conducted to evaluate the reduction of DOC and THMFP under variou sconditions of pH, iron salts dosages, hydrogen peroxide dosages and processcombination. Finally, we will discuss the relationship among THMFP, DOC andUV254. The effect of pH on THMFP reduction by Fenton's reagent and coagulationrange 3.0-4.0 and 4.0-5.0. It is effective and economical if we use theprocess combination to treat the polluted raw waters at pH 5.0. At this range(pH 5.0), hydrogen peroxide can't enhance the effect of ferric (Fe3+=4mg/L)coagulation, but it can preoxidize phenol. Relatively , hydrogen peroxide canenhance the effect of ferrous (Fe2+=4mg/L) coagulation and preoxidation. Whenthe combination of chemical coagulation and Fenton's process is in use, coagulant, ferrous, and hydrogen peroxide are combined in the rapid-mix basin,and the equipment cost and the effect are better than those isolated process.Compare Fenton's Process with chemical coagulation, when 4mg/L ferrous iscombined with 2mg/L hydrogen peroxide, each mg of iron salts can remove0.404mg DOC, 0.0799mg THMFP, and 0. 138mg phenol; when there are 2mg/Lferrous, 2mg/L ferric, and 2mg/L hydrogen peroxide, each mg of iron salts canremove 0.771mg DOC, 0.1055mg THMFP, and 0.140mg phenol. This shows that thecombination of chemical coagulation and Fenton's Process is better thanFenton's Process. Besides ferric, when alum is combined in use with Fenton'sProcess, the same effect still exists, which shows that the combination ofchemical coagulation and Fenton' s Process can not only remove organic, andreduce THMFP, but also p reoxidize phenol effectively. As to THMFP and DOC,the relative coefficients (R) of raw water, synthetic water, and polluted rawwater are 0.834, 0.983, and 0.907, which show that there is good relationshipbetween THMFP and DOC. Because organic matter in raw water and synthetic wateris simpler, the relative coefficients between THMFP and UV254 are 0.828 and0.934. As to polluted raw water because effect of notably ferrous iron,nitrate, nitrite, and bromide, the relative coefficient is just 0.214, which shows that UV254 is inadequate as surrogate when interference is occurred insample.