BIOREMEDIATION OF PETROLEUM HYDROCARBON CONTAMINAUTS USING ANIONICSURFACTANTS

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 09680549
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 環境保全
• Research Institution: KUMAMOTO UNIVERSITY
• Principal Investigator: ROUSE Joseph d Kumamoto University, Civil Faculty of Engineering, Associate Professor, 工学部, 助教授 (80284743)
• Co-Investigator(Kenkyū-buntansha): MORIMURA Shigeru Kumamoto University, Graduate School of Science and Technology, Associate Professor, 大学院・自然科学研究科, 講師 (20230146) ; FURUKAWA Kenji Kumamoto University, Civil Faculty of Engineering, Professor, 工学部, 教授 (60029296)
• Project Period (FY): 1997 – 1998
• Keywords: anionic surfactants / bioremediation / biodegradation / mineralization / hydrocarbons / naphthalene / phenanthrene / subsurface

Research Abstract

Research was conducted to investigate the influences of anionic alkyl diphenyloxide disulfonate (DPDS) surfactants (with C12 and C16 alkyl moieties) an bioremediation of hydrocarbons. Potential for enhancement in degradation of water soluble naphthalene was seen in C12-DPDS amended aqueous assays with concentrations up to 3.0 mM--slightly above the critical micelle concentration (CMC). However, the overall trend of results indicated a decreasing efficiency of degradation with increasing surfactant concentration with no significance to the CMC. Assays with C16-DPDS also demonstrated a decreasing trend in degradation rates with increasing surfactant concentration but with no indication of enhancement.
In soil-slurries with phenanthrene, surfactant-free controls and samples with very low surfactant additions (of both C12- and C16-DPDS) had equally strong, sustained mineralization responses. About 40 days later, samples containing mid level (sub-CMC) C12-DPDS had responses similar to the co ntrols. After 3 months, a supra-CMC C12-DPDS sample had a strong mineralization response. The nature of mineralization response in surfactant-free and supra-CMC surfactant-amended assays indicated that different routes of substrate utilization were involved.
In saturated soil systems (mud) significant mineralization only occurred with the surfactant-free controls and the samples with very low surfactant additions over about 20 weeks of testing. Surfactant sorbed in the soil was influential because the 1st order degradation coefficients were higher in the presence of low levels of surfactant. In particular, the C12-DPDS amended samples were, enhanced by a factor of 5 over the surfactant-free controls. As with naphthalene degradation and phenanthrene soil-slurry assays, the greater potential for enhancement was with C12-DPDS suggesting a greater compatibility of this surfactant with cell membranes.
Surfactant degradation assays in soil-slurry systems indicated the potential for a very gradual degradation of both C12-and c16-DPDS at low concentrations. For the surfactant to have some degree of recalcitrance with the possibility of eventual disappearance is an important factor to consider in surfactant-aided subsurface remediation.