科研之友
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摘要
Remediation of contaminated groundwater is an expensive and lengthy process. Permeable reactive barrier of metallic iron (Fe-0 PRB) is one of the leading technologies for groundwater remediation. One of the primary challenges for the Fe-0 PRB technology is to appropriately size the reactive barrier (length, width, Fe-0 proportion and nature of additive materials) to enable sufficient residence time for effective remediation. The size of a given Fe-0 PRB depends mostly on accurate characterization of: (i) reaction mechanisms and (ii) site-specific hydrogeologic parameters. Accordingly, the recent revision of the fundamental mechanisms of contaminant removal in Fe-0/H2O systems requires the revision of the Fe-0 PRB dimensioning strategy. Contaminants are basically removed by adsorption, co-precipitation and size exclusion in the entire Fe-0 bed and not by chemical reduction at a moving reaction front. Principle calculations and analysis of data from all fields using water filtration on Fe-0 bed demonstrated that: (i) mixing Fe-0 and inert additives is a prerequisite for sustainability, (ii) used Fe-0 amounts must represent 30-60 vol.% of the mixture, and (iii) Fe-0 beds are deep-bed filtration systems. The major output of this study is that thicker barriers are needed for long service life. Fe-0 filters for save drinking water production should use several filters in series to achieve the treatment goal. In all cases proper material selection is an essential issue.
- 出版日期2010-10-1
