title: Development of a slow polycolloid-releasing substrate (SPRS) biobarrier to remediate TCE-contaminated aquifers.
abstract: In this study, an in situ slow polycolloid-releasing substrate (SPRS) biobarrier system was developed to continuously provide biodegradable substrates for the enhancement of trichloroethylene (TCE) reductive dechlorination. The produced SPRS contained vegetable oil (used as a slow-released substrate), cane molasses [used as an early-stage (fast-degradable) substrate], and surfactants [Simple Green (SG) and soya lecithin (SL)]. An emulsification study was performed to evaluate the globule droplet size and stability of SPRS. The distribution and migration of the SPRS were evaluated in a column experiment, and an anaerobic microcosm study was performed to assess the capability of SPRS to serve as a slow and long-term carbon-releasing substrate for TCE dechlorination. The results show that a stable oil-in-water (W/O, 50/50) emulsion (SPRS) with uniformly small droplets (D₁₀, 0.93 μm) has been produced, continuously supplying primary substrates. The emulsion containing the surfactant mixture (with 72 mg/L SL and 71 mg/L SG) had a small absolute value of the zeta potential, which reduced the inter-particle repulsion, leading the emulsion droplets to adhere to one another after collision. The addition of SPRS creates anaerobic conditions and leads to a more complete and thorough removal of TCE through biodegradation and sorption mechanisms.
authors.affiliation: Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
authors.forename: S H
authors.initials: SH
authors.lastname: Liang
authors.affiliation: Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
authors.forename: Y C
authors.initials: YC
authors.lastname: Kuo
authors.affiliation: Institute of Urban Environment, Chinese Academy of Science, Xiamen, China.
authors.forename: S H
authors.initials: SH
authors.lastname: Chen
authors.affiliation: Formosa Plastics Corp., Taiwan, Kaohsiung, Taiwan.
authors.forename: C Y
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan. Electronic address: jkao@mail.nsysu.edu.tw.
authors.forename: C M
authors.initials: CM
authors.lastname: Kao
mesh_terms: D000327:Adsorption; D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D004655:Emulsions; D005232:Fatty Acids, Volatile / Q000378:metabolism; D060587:Groundwater; D054709:Lecithins / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D008965:Molasses; D013501:Surface-Active Agents / Q000737:chemistry; D014241:Trichloroethylene / Q000737:chemistry / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004655:Emulsions; D005232:Fatty Acids, Volatile; D054709:Lecithins; D008055:Lipids; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; D014241:Trichloroethylene