Methods for determining NAPL source zone remediation efficiency of in-situ flushing technologies

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:567808

Jawitz, J W; Sillan, R K; Annable, M D; Rao, P S.C. ^[1]

---

1. Univ. of Florida, Gainesville, FL (United States)

In-situ flushing technologies are often evaluated using small pilot-scale tests conducted within the contaminated aquifer targeted for remediation. If more than one technology has been evaluated, the site manager and regulatory agencies must determine which is best for full-scale remediation. Data from two in-situ flushing studies conducted at Hill AFB, Utah are analyzed here to investigate the best approaches for comparing technologies based on effectiveness and efficiency for source zone remediation. The technologies are compared using partitioning tracers, core sample analysis and mass removal by flushing. A NAPL remediation efficiency measure is derived using each of these measures. The critical issue of differences in the initial condition is addressed with regard to how this may bias the evaluation of each technology. Differences which were considered include variability in hydraulic conductivity field, NAPL distribution, and NAPL composition. The Hill AFB studies were conducted within an extensive NAPL source zone. Cosolvents and a surfactant/cosolvent mixture were the two flushing methods tested. The cosolvent flushing solution consisted of a completely miscible ethanol/pentanol/water mixture, while the surfactant/cosolvent system was a Winsor Type I single-phase microemulsion of a nonionic surfactant and pentanol. The two flushing technologies were evaluated in very similar sheet pile-isolated test cells, with similar flushing protocols providing consistent data sets with which to make comparisons. Results indicated that both technologies were effective, removing approximately 95% of the NAPL, according to soil core analyses. In addition, the efficiencies of both technologies were similar, removing n-decane 10{sup 6} times more efficiently than pump-and-treat would have.

• OSTI ID: 567808
• Report Number(s): CONF-971032--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
ENVIRONMENTAL ENGINEERING
FLUID INJECTION
GROUND WATER
IN-SITU PROCESSING
MILITARY FACILITIES
NONAQUEOUS SOLVENTS
REMEDIAL ACTION
TECHNOLOGY ASSESSMENT
UTAH