A pilot-scale, landfarm treatability study was designed to demonstrate improved bioremediation of PAHs using bioaugmentation in combination with bulking agents and slow release nitrogen (biostimulation). Three galvanized steel water troughs were used to contain the contaminated soil and the various amendments in the pilot facility. Pan 1 was left untreated. Pan 2 was amended with bulking agent and slow-release organic nutrient. Pan 3 was amended with the bulking agent, nutrients, and bioaugmented with a known biosurfactant producer, a Pseudomonas sp. All pans were mixed weekly using a mechanical rotary cultivator and soil moisture was maintained at 50-80% of the field moisture capacity (FMC). Initial PAH concentrations were 10,500, 7,200 and 7,300 mg/kg for Pan 1, 2, and 3, respectively. After 16 months, only 12% degradation was observed in Pan 1 (control). An initial lag was observed for Pan 2 and Pan 3. Following this, Pan 3 exhibited a higher degradation rate that was maintained through month 7. At 16 months, Pans 2 and 3 showed 86% and 87% degradation of total PAH, respectively. Contaminant reduction extended into the 4-ring homologues (fluoranthene, pyrene) and the BaP TEQ compounds (chrysene, benzo(a)anthracene). The results suggest landfarming is possible for sites with high concentrations of PAHs (> 10,000 mg/kg) by using these alternative treatment strategies.
展开▼
