Dense Nonaqueous Phase Liquids (DNAPLs)
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Permeable Reactive Barriers
Creosote DNAPL from wood-preserving sites and coal tar-contaminated soils at former manufactured gas plants and coking facilities act as a long-term sources of polycyclic aromatic hydrocarbons (PAHs). A small number of full-scale PRBs have been installed at these types of sites to address contaminated groundwater by encouraging aerobic degradation of the dissolved contaminants.
For Further Information
Case Study Bulletin: Laboratory and Field Evaluation of a Biological Permeable Reactive Barrier for Remediation of Organic Contaminants in Soil and Groundwater
CL:AIRE (Contaminated Land: Applications in Real Environments), CSB-3, 4 pp, 2005
In 2001, a modular reactive barrier was installed at small former gasworks site in Portadown, Northern Ireland, to study of the efficacy of a bio-based PRB for remediating contaminants dissolving from coal tar and other manufactured gas plant wastes. The design of the full-scale PRB includes 330 m of slurry wall (to 13 m depth) and a 20 cubic m air sparged bioreactor and GAC reactor placed in sequence with a pea-gravel mixing zone before and behind the reactive cell.
Former Industrial Site, Brunn am Gebirge, Austria
Remediation Technologies Development Forum (RTDF), Permeable Reactive Barrier Installation Profiles website.
In 1999, a full-scale PRB system was installed at the site of a former tar plant and linoleum production plant in Brunn am Gebirge, Austria. Designed to adapt to the landscaping and architecture of a business park, the system combines a hydraulic barrier 2 to 5 ft thick with four adsorptive reactors containing a total of 23 tons of activated carbon. PAHs, phenols, benzene, toluene, ethylbenzene, xylenes, hydrocarbons, TCE, and cis-DCE are the contaminants of concern at this site.
In-Situ Soil and Groundwater Bioremediation Techniques and Applications
Jarno Laitinen, thesis, Tampere Polytechnic, Finland, 91 pp, 2006
This work provides a brief case study in Chapter IV of a pilot-scale biowall installation for remediation of groundwater contaminants emanating from a creosote-contaminated site. The biowall is an underground in situ aerobic bioreactor operated by infiltration of nutrients and air at different levels. The biowall began functioning in September 2005.
Remediation System Evaluation (RSE), Moss-American Superfund Site, Milwaukee, Wisconsin
U.S. EPA, Office of Solid Waste and Emergency Response.
EPA 540-R-11-018, 60 pp, 2011
The 88-acre site comprises a former wood treating facility plus several miles of the Little Menomonee River and its adjacent floodplain. The facility used creosote for wood preservation, and site contaminants include anthracene, benzene, benzo(a)pyrene, benzo(b)fluoranthene, chrysene, fluoranthene, fluorene, naphthalene, and pyrene. The groundwater remedy consists of a funnel-and-gate system to capture and treat the contaminated groundwater prior to discharge to the Little Menomonee River. A sheet-pile containment wall funnels the groundwater through two sets of treatment gates. These permeable treatment zones consist of an area backfilled with a mixture of clean sand/soil pierced by a line of injection wells at the upgradient edge of the gate area. A solution containing potassium nitrate and potassium phosphate was added at Gate 1 from June 2001 through October 2002 using, but nutrient augmentation was discontinued due to inconclusive evidence that it enhanced biodegradation. Air injection has been the only treatment since that time. This report focuses on optimizing system performance and addressing the stagnant groundwater zone that is limiting flow through the treatment gates and elevated contaminant concentrations in the vicinity of one monitoring well. This report provides a brief background on the site and then discusses current operations and recommendations for changes, with potential cost impacts.