|
|
| Line 1: |
Line 1: |
| − | Emulsified Vegetable Oil (EVO) is commonly added as a slowly fermentable substrate to stimulate ''in situ'' anaerobic bioremediation. This article summarizes information about EVO transport in the subsurface, consumption during anaerobic bioremediation, and methods for effectively distributing EVO throughout the target treatment zone.
| + | Permeable reactive barriers (PRBs) are ''in situ'' treatment zones created below ground to clean up contaminated groundwater. PRBs take advantage of natural groundwater migration to transport contaminants to a defined treatment zone. Contaminants are removed from groundwater in the PRB and treated groundwater passes through the permeable zone; eventually a “clean front” is created on the down-gradient side of the PRB. Zerovalent Iron (ZVI) was the first reactive material used in PRBs for groundwater remediation and it continues to be the primary material used in the construction of these treatment systems. ZVI PRBs can treat groundwater contaminated with chlorinated solvents and their breakdown products such as tetrachloroethene (PCE), trichloroethene (TCE), ''cis''-1,2-dichloroethene (''cis''-DCE), vinyl chloride (VC), 1,1,1-trichloroethane (1,1,1-TCA), 1,1-dichloroethane (1,1-DCA), 1,2-dichloroethane (1,2-DCA), chloroform, and carbon tetrachloride; explosives such as TNT and RDX; cations of Pb, Cd, Ni, Zn, and Hg; and anions of Cr, As, Sb, Se, U, and Tc. |
| | | | |
| | <div style="float:right;margin:0 0 2em 2em;">__TOC__</div> | | <div style="float:right;margin:0 0 2em 2em;">__TOC__</div> |
| Line 5: |
Line 5: |
| | | | |
| | '''Related Article(s):''' | | '''Related Article(s):''' |
| − | *[[Bioremediation - Anaerobic |Anaerobic Bioremediation]]
| |
| − | *[[Bioremediation - Anaerobic Design Considerations| Anaerobic Bioremediation Design Considerations]]
| |
| − | *[[Chlorinated Solvents]]
| |
| − |
| |
| − |
| |
| − | '''CONTRIBUTOR(S):''' [[Dr. Robert Borden, P.E.]]
| |
| − |
| |
| − |
| |
| − | '''Key Resource(s):'''
| |
| − |
| |
| − | *[[media:2017-Borden-Post-Remediation_Evaluation_of_EVO_Treatment.pdf| Post-Remediation Evaluation of EVO Treatment – How Can We Improve Performance?]]<ref name = "Borden2017EVO">Borden, R.C., 2017. Post-Remediation Evaluation of EVO Treatment: How Can We Improve Performance. Environmental Security Technology Certification Program, Alexandria, VA. ER-201581[[media:2017-Borden-Post-Remediation_Evaluation_of_EVO_Treatment.pdf| Report.pdf]]</ref>
| |
| − | *[[media:2006-Solutions-IES-Protocol_for_Enhanced_In_Situ_Bioremediation.pdf| Protocol for Enhanced In Situ Bioremediation Using Emulsified Edible Oil (Solutions-IES, 2006)]]<ref>Solutions-IES, 2006. Protocol for Enhanced In Situ Bioremediation Using Emulsified Edible Oil. Environmental Security Technology Certification Program, Arlington, VA, USA. ER 200221 [[media:2006-Solutions-IES-Protocol_for_Enhanced_In_Situ_Bioremediation.pdf| Report.pdf]]</ref>
| |
| − |
| |
| − | ==Introduction==
| |
| − |
| |
| − |
| |
| − |
| |
| − | {|
| |
| − | |-
| |
| − | |align=left|- rapid flocculation|| 0 mV|| < || zeta potential || <|| -5 mV
| |
| − | |-
| |
| − | |align=left|- incipient instability|| -10 mV || < || zeta potential || <|| -30 mV
| |
| − | |-
| |
| − | |align=left|- moderate stability|| -30 mV|| < || zeta potential || <|| -40 mV
| |
| − | |-
| |
| − | |align=left|- good stability || -40 mV|| < || zeta potential || <|| -61 mV
| |
| − | |-
| |
| − | |align=left|- excellent stability|| || || zeta potential || <|| -61 mV
| |
| − | |}
| |
| − |
| |
| − |
| |
| − |
| |
| − | {| class="wikitable" style="text-align: center;"
| |
| − | |+ colspan="3" | Table 1. Effect of solution composition on zeta potential
| |
| − | |-
| |
| − | ! rowspan="2" | Colloid
| |
| − | ! colspan="2" | Average Zeta Potential (mV) (standard deviation)
| |
| − | |-
| |
| − | ! DI Water
| |
| − | ! 200 mg/L CaCl<sub>2</sub>
| |
| − | |-
| |
| − | | SA17 Soil 15-23’ || -29.4 (0.8) || -8.5 (0.5)
| |
| − | |-
| |
| − | | SA17 Soil 30-40’|| -22.3 (0.9) || -7.5 (0.9)
| |
| − | |-
| |
| − | | OU2 Soil 37-40’ || -19.9 (0.5) || -12.2 (0.9)
| |
| − | |-
| |
| − | | EOS 598B42|| -43.0 (0.7) || -10.3 (0.4)
| |
| − | |}
| |
| − |
| |
| − | {| class="wikitable" style="text-align: center;"
| |
| − | |+ colspan="3" | Table 2. Oil retention in laboratory columns flushed with EOS598B42 and either DI water or 200 mg/L CaCl<sub>2</sub>
| |
| − | |-
| |
| − | ! rowspan="2" | Aquifer Material
| |
| − | ! colspan="2" | Average Oil Retention (g oil/g sediment) (standard deviation)
| |
| − | |-
| |
| − | ! DI Water
| |
| − | ! 200 mg/L CaCl<sub>2</sub>
| |
| − | |-
| |
| − | | SA17 Zone B || 0.0027 (0.0027)|| 0.0133 (0.0060)
| |
| − | |-
| |
| − | | OU2 || 0.0144 (0.0018)|| 0.0381 (0.0114)
| |
| − | |}
| |
| − |
| |
| − |
| |
| − |
| |
| − | ==Summary==
| |
| − | Emulsified Vegetable Oil (EVO) is commonly added as a slowly fermentable substrate to stimulate ''in situ'' anaerobic bioremediation. Commercially available EVO typically contains a mixture of 45 to 60% vegetable oil present in small (0.5 to 2.0 µm) droplets, more readily fermentable soluble substrates (e.g. fatty acids or alcohols), surfactants, nutrients and water. Oil droplets are retained by aquifer material when they collide with sediment surfaces and stick (referred to as interception). The tendency of oil droplets to stick to aquifer material varies due to a number of factors including pH, droplet and matrix grain surface coatings, ionic strength, surface roughness, sediment surface charge heterogeneity, and blocking of the sediment surface with previously retained droplets. Following injection, the vegetable oil is hydrolyzed to glycerol and long-chain fatty acids (LCFAs), which are subsequently fermented to hydrogen (H<sub>2</sub>) and acetate. The rate of LCFA fermentation and resulting H<sub>2</sub> production is limited by sorption to sediment surfaces and/or precipitation with divalent cations (Ca<sup>+2</sup>, Mg<sup>+2</sup>, Mn<sup>+2</sup>, Fe<sup>+2</sup>). Since H<sub>2</sub> is rapidly consumed near where it is produced, the oil droplets should be distributed as uniformly as possible throughout the target treatment zone. This involves injecting sufficient EVO and sufficient water to distribute the EVO throughout the treatment zone.
| |
| − |
| |
| − | ==References==
| |
| − |
| |
| − | <references/>
| |
| − |
| |
| − | ==See Also==
| |
| − | *[https://www.serdp-estcp.org/Program-Areas/Environmental-Restoration/Contaminated-Groundwater/ER-1205/ER-1205 Development of Permeable Reactive Barriers Using Edible Oils]
| |
| − | *[https://www.serdp-estcp.org/Program-Areas/Environmental-Restoration/Contaminated-Groundwater/ER-200221/ER-200221 Edible Oil Barriers for Treatment of Chlorinated Solvent- and Perchlorate-Contaminated Groundwater]
| |
| − | *[https://www.serdp-estcp.org/Tools-and-Training/Environmental-Restoration/Groundwater-Plume-Treatment/Protocol-for-Enhanced-In-Situ-Bioremediation-Using-Emulsified-Edible-Oil Protocol for Enhanced In Situ Bioremediation Using Emulsified Edible Oil]
| |
| − | *[https://www.serdp-estcp.org/Tools-and-Training/Environmental-Restoration/Groundwater-Plume-Treatment/Emulsion-Design-Tool-Kit Emulsion Design Tool Kit]
| |
Permeable reactive barriers (PRBs) are in situ treatment zones created below ground to clean up contaminated groundwater. PRBs take advantage of natural groundwater migration to transport contaminants to a defined treatment zone. Contaminants are removed from groundwater in the PRB and treated groundwater passes through the permeable zone; eventually a “clean front” is created on the down-gradient side of the PRB. Zerovalent Iron (ZVI) was the first reactive material used in PRBs for groundwater remediation and it continues to be the primary material used in the construction of these treatment systems. ZVI PRBs can treat groundwater contaminated with chlorinated solvents and their breakdown products such as tetrachloroethene (PCE), trichloroethene (TCE), cis-1,2-dichloroethene (cis-DCE), vinyl chloride (VC), 1,1,1-trichloroethane (1,1,1-TCA), 1,1-dichloroethane (1,1-DCA), 1,2-dichloroethane (1,2-DCA), chloroform, and carbon tetrachloride; explosives such as TNT and RDX; cations of Pb, Cd, Ni, Zn, and Hg; and anions of Cr, As, Sb, Se, U, and Tc.
Related Article(s):
