Numerical Simulation of a Natural Attenuation Experiment with a Petroleum Hydrocarbon NAPL Source

• DOI: 10.1111/j.1745-6584.2001.tb02482.x
• Publication Date: 2005-12-13T18:24:07Z
• Authors: J. Steven Brauner; Mark A. Widdowson
• Keywords: BTEX; Biostimulation

Abstract A three‐dimensional solute transport model with biological reactions is presented for simulating the natural attenuation study (NATS) at Columbus Air Force Base in eastern Mississippi. NATS consisted of release a petroleum‐based nonaqueous phase liquid (NAPL) and subsequent monitoring BTEX (benzene, toluene, ethylbenzene, p‐xylene), naphthalene, decane, bromide shallow, unconfined aquifer. Conceptual mathematical models were developed NAPL source release, sequential aerobic/anaerobic biodegradation, sorption during NATS. multiple species, code (SEAM3D) was used to simulate fully aerobic, nitrate‐reducing, ferrogenic, methanogenic hydrocarbon biodegradation. Simulation results matched individual concentration distributions collected five‐ nine‐months following release. SEAM3D mass‐balance calculations t = nine months indicated that 49% mass dissolved into aqueous consumed by 13% this sorbed, remaining 38% present phase. Mass further aerobic biodegradation accounted majority (46% biodegraded mass), followed ferrogenesis (28%), nitrate‐reduction (21%), methanogenesis (5%). Model particularly sensitive rate, initial ferric iron (Fe[III]) concentration, utilization rates, condition anaerobic microbial populations, dispersivity.