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EPA-99-GA103-03-A236-9

099

875 千元

2010/12/29

2011/12/28

張益國

土污基管會

尤衍翔

中臺科技大學

土壤及地下水

沉積物、溶出試驗、水力分離

Sediments, leaching tests, hydrocyclone separation

許益源

張益國

04-22391647#6856

ykchang@ctust.edu.tw

本研究應用多種溶出試驗，包括pH對初始酸鹼添加之溶出影響等溶出行為試驗(pH-dependent test)、管柱試驗(Percolation test)驗證港池沉積物重金屬溶出特性，並搭配歐盟LeachXS專家系統分析沉積物中重金屬於pH依存度之溶出行為，研判重金屬溶出或穩定之可能機制。隨後搭配水力分離技術開發，以水力漩流分離器(Hydrocyclone)分離重金屬含量較高之細顆粒港灣沉積物，再以重金屬於pH依存度之溶出行為為基礎，酸洗及螯合萃洗濃集沉積物中重金屬。並對經/未經水力分離處理、酸洗及螯合萃洗之港灣沉積物進行長期穩定特性驗證，驗證其粗細顆粒之重金屬溶出行為，評估水力漩流分離處理效能及促進粗顆粒（含重金屬量較少之顆粒）再利用。 研究結果顯示，沉積物中73.9%顆粒粒徑小於63µm；另由微波消化金屬總量分析結果可知，Cu、Zn為沉積物中含量較高之重金屬。以水力漩流分離器分離細顆粒沉積物可將細泥(＜63µm) 分離出38.07%-57.7%，具一定顆粒分離效果。再以HCl、H2SO4、EDTA、Citric acid等試劑對沉積物中Cu、Zn重金屬進行移除試驗，對Cu之萃取率分別為13.9%、30.7%、32.6%、17.2%；對於Zn之萃取率分別為8.7%、12.6%、36.8%、10.9%，其中以EDTA效果最好，H2SO4效果次之。惟EDTA可有效萃洗Cu、Zn，但亦增加了浚泥中Cu、Zn重金屬離子之移動性，因此殘存之重金屬變得容易溶出。最後，探討利用添加土地改良劑處理沉積物之效能，評估資材化處理可行性。結果發現，7天抗壓強度可達26.1 kg/cm2單軸抗壓強度水準，且其資材化塊材幾乎不溶出Cu、Zn重金屬，顯示該資材化塊材具重金屬長期穩定性。未來應可考慮將沉積物與土地改良劑或水泥混拌製成資材化塊材，可進行工程應用。

沉積物、溶出試驗、水力分離

張益國.pdf

2MB

2012/2/1 上午 12:00:00

Contaminated sediments in the harbors remain being a significant issue during dredging operations. Numerous methods have been suggested in recent years for remove, treating and beneficial uses of harbor sediments. In this research, the basic characteristics and the geochemistry of metals in the sediments were studied, and which were subjected to pH-dependent leaching test, percolation test and column test. The results of experimental leaching tests of harbor sediments are compared with computer calculations, the LeachXS expert system. This computer program allows to predict the metal concentrations and the pH of leaching solution at equilibrium, along with the minerals that precipitate and the organic characteristics react with the metal ions forming into stable organic metal compounds. The result of laboratory research showed that the content of heavy metals contaminants is primarily governed by the grain size. The optimum separation process was approached through hydrocyclone separation and sieving. The sediments might be classified as a clean sand product (d ≧ 63 µm) of 26.1% which could be directly reused, and a contaminated fine sediment with silt and clay fraction (d < 63 µm) of 73.9%. Heavy metal contaminants tend to adsorb on the fine sediments, and thus further treatments such as chemical washing and stabilization/modification are needed before deposition and recycling. Results from the chemical washing (extraction) technique showed that under 0.01M EDTA and H2SO4 as reagents with a sediment/reagent ratio of 1/10, contact time of 30 minutes, the Cu removal efficiency was 30.7% and 32.6%, respectively; the Zn removal efficiency was 12.6% and 36.8%, respectively. Besides that, stabilization/modification processes (adding with soil amelioration products) can make the heavy metal containing sediment to be low-matrix leachability and which might be reused as construction material. Thus, this research projects might provide a basic understanding, and the statistic correlation among the sediment characteristics, metal concentration and the possible controlling factors.

Sediments, leaching tests, hydrocyclone separation