Bioenhancement of NAPL pool dissolution: Experimental evaluation

Eric A. Seagren, Bruce E. Rittmann, Albert J. Valocchi

Research output: Contribution to journalArticlepeer-review

Abstract

Experiments were conducted to quantify nonaqueous phase liquid (NAPL) pool dissolution and its enhancement by in situ biodegradation. The experiments were performed using square cross-section, glass-bead packed column reactors with a small pool of a toluene-in-dodecane mixture (toluene mole fraction, Xtol≈0.02 or 0.09). Experimental quasi-steady-state toluene dissolution fluxes were determined using a 14C-carbon mass-balance approach during water flushing with and without biodegradation. The experiments demonstrated a statistically significant bioenhancement of the toluene dissolution flux of up to roughly twofold at average pore water velocities of approximately 0.1 and 1 m/day when the toluene mole fraction was low (≈0.02); however, little or no bioenhancement was observed with the higher mole fraction (≈0.09). Although it cannot be determined conclusively, the weight of evidence based on biomass measurements and model analyses suggests that the reduced bioenhancement for the high mole fraction was due to higher dissolved toluene concentrations, which may have caused toxicity effects. Importantly, even though NAPL dissolution was not bioenhanced in every case, the biodegradation reduced toluene concentrations to low levels in the reactor effluents.

Original languageEnglish (US)
Pages (from-to)57-85
Number of pages29
JournalJournal of Contaminant Hydrology
Volume55
Issue number1-2
DOIs
StatePublished - Mar 19 2002

Keywords

  • Bioenhancement
  • Dissolution
  • Experimental studies
  • Nonaqueous phase liquid (NAPL)
  • Pool
  • Toxicity

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology

Fingerprint Dive into the research topics of 'Bioenhancement of NAPL pool dissolution: Experimental evaluation'. Together they form a unique fingerprint.

Cite this