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Title: Nontoxic chemical process for in situ permeability enhancement and accelerated decontamination of fine-grain subsurface sediments

The remediation of heterogeneous subsurfaces is extremely time consuming and expensive with current and developing technologies. Although such technologies can adequately remove contaminants in the high hydraulic conductivity, coarse-grained sediments, they cannot access the contaminated low hydraulic conductivity fine-grained sediments. The slow bleed of contaminants from the fine-grained sediments is the primary reason why subsurface remediation is so time-consuming and expensive. This invention addresses the problem of remediating contaminated fine-grained sediments. It is intended that, in the future, a heterogeneous site be treated by a hybrid process that first remediates the high hydraulic conductivity, coarse-grained sediments, to be followed by the process, described in this invention, to treat the contaminated low hydraulic conductivity fine-grained sediments. The invention uses cationic flocculents and organic solvents to collapse the swelling negative double layer surrounding water saturated clay particles, causing a flocculated, cracked clay structure. The modification of the clay fabric in fine-grained sediments dramatically increases the hydraulic conductivity of previously very tight clays many orders of magnitude.
Inventors:
 [1];  [2];  [3]
  1. (Livermore, CA)
  2. (Tracy, CA)
  3. (Oakland, CA)
Issue Date:
OSTI Identifier:
870778
Assignee:
Regents of University of California (Oakland, CA) LLNL
Patent Number(s):
US 5593248
Contract Number:
W-7405-ENG-48
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Country of Publication:
United States
Language:
English
Subject:
nontoxic; chemical; process; situ; permeability; enhancement; accelerated; decontamination; fine-grain; subsurface; sediments; remediation; heterogeneous; subsurfaces; extremely; time; consuming; expensive; current; developing; technologies; adequately; remove; contaminants; hydraulic; conductivity; coarse-grained; access; contaminated; fine-grained; slow; bleed; primary; reason; time-consuming; addresses; remediating; intended; future; site; treated; hybrid; remediates; followed; described; treat; cationic; flocculents; organic; solvents; collapse; swelling; negative; double; layer; surrounding; water; saturated; clay; particles; causing; flocculated; cracked; structure; modification; fabric; dramatically; increases; previously; tight; clays; magnitude; hydraulic conductivity; organic solvents; organic solvent; double layer; chemical process; remove contaminants; surrounding water; time consuming; toxic chemical; subsurface sediment; layer surrounding; /405/166/