Remediation Technology Demonstration Project Profiles
In Situ Chemical Oxidation Using Persulfate and Potassium Permanganate at an Unknown Location
Last Updated: December 3, 2004 |
||
| Site Identifying Information | ||
| Site Name, Location: | Xpert Design and Diagnostics - TCE-Contaminated Site, Location Unknown, | |
| Cleanup Program: | Not Specified | |
| Entity Responsible for Cleanup: | Not Specified | |
| Site Type: | Not Specified | |
| Government Affiliation: | Non-Federal | |
| | ||||||||||
| Project Information | ||||||||||
| Project Name: | In Situ Chemical Oxidation Using Persulfate and Potassium Permanganate at an Unknown Location | |||||||||
| Project Status: | Complete | |||||||||
| Contaminants Treated: |
| |||||||||
| Media Treated: |
| |||||||||
| Demonstration Technology and Type: | Permanganate (In Situ Chemical Oxidation) (In Situ Physical/Chemical) |
|||||||||
| Geology and Hydrogeology: | Site has a 10-foot thick semi-confined, sand and gravel aquifer with a hydraulic conductivity of 0.29 cm/sec and a groundwater velocity of 5 ft/day. | |||||||||
| Demonstration Start Date: | 11/1998 | |||||||||
| Demonstration Completion Date: | 8/1999 (Actual) | |||||||||
| Demonstration Year: | 1999 | |||||||||
| Year of Publication: | 2003 | |||||||||
| Goal of the Demonstration: | To understand the behavior of the reaction between the oxidants and the target VOCs, and between the oxidants and the native soil materials under field conditions. | |||||||||
| Design and Operations: | United Technologies Corporation in conjunction with the University of Connecticut's Environmental Research Institute has developed and patented a novel in-situ chemical oxidation process to mineralize VOCs using persulfate and permanganate either sequentially or simultaneously. The vendor identified the primary benefits of the patented process are to (1) minimize manganese oxide precipitation by satisfying the non-target oxidant demand by persulfate injection prior to permanganate injection, and (2) reduce the total amount of oxidant required for mineralization of target VOCs. Based on the results of laboratory treatability studies and a 3-dimensional high-resolution site characterization, a large-scale pilot test was conducted from November 1998 to August 1999. The target test area comprised of two treatment zones, each sized approximately 160 ft long, 175 ft wide, and 10 ft thick. The oxidant injection was performed through two rows of injection wells with 6 injection locations in each row. A total of 8,200 kg of sodium persulfate was injected over a period of 64 days at a concentration of 2 g/L and a rate of 4.33 liters per minute (Lpm). Following this addition, a total of 45,000 kg of potassium permanganate was injected over a period of 172 days at concentrations of 5 and 10 g/L and rates ranging from 1.57 to 3.78 Lpm. Monitoring was performed via 80 discrete monitoring points located at 36 wells downgradient of the injection wells. Monitoring was conducted during injection and seven times following injection (August and December 1999; March, June, September, and December 2000; and June 2001). Two types of monitoring were conducted: geochemical (pH, oxidation reduction potential [ORP], conductivity, and temperature) and chemical (VOCs, chloride, residual sodium persulfate, residual potassium permanganate, sodium, sulfate, potassium, and manganese). | |||||||||
| Performance Data Relevant to Demonstration Goals: | Based on limited sampling data for TCE, cis-DCE, and vinyl chloride concentrations collected during the seven post-monitoring events, a 735-ft long by 288-ft wide modeling grid was created using GMS software for data interpolation. The average interpolated concentration for the modeled zone indicated a decrease in TCE concentrations from 3,538 to 1,688 ug/L, while average cis-DCE concentrations decreased from 9,715 to 4,684 ug/L. Average vinyl chloride concentrations were relative stable through the post-injection period indicating relatively equivalent rates of vinyl chloride production (from cis-DCE degradation) and degradation. Average post-injection chloride concentrations have remained elevated (36 to 41 mg/L) when compared to the pre-injection concentration of 17 mg/L. Daughter to parent compound ratios (cis-DCE:TCE) and (vinyl chloride:cis-DCE) increased by approximately 80% and 70%, respectively. A chloride mass balance was performed because chloride is a non-sorbing chlorinated VOC degradation end-product. During the post-injection monitoring period through September 2000, a net increase of approximately 1,669 kg in chloride mass was observed, which equates to approximately 2,060 kg of equivalent TCE destruction. To determine the role of sulfate reduction in the ongoing reductive dechlorination process, additional analyses, (hydrogen, sulfate, iron, and phospholipids fatty acid (PLFA) sampling) were conducted in May 2000 at 3 locations. These locations showed high concentrations of TCE and its reductive daughter products during the previous quarterly monitoring event (March 2000), and were assumed to be likely locations where TCE reduction was ongoing. Hydrogen sampling was done to support the conclusion that reductive dechlorination of TCE was occurring; hydrogen concentration ranged from 1.36 to 1.69 nano-moles/liter. Sulfate concentrations ranged from 43 to 430 mg/L, which support the growth of sulfate-reducing bacteria in the aquifer. PLFA analysis identified Gram Negative bacteria and the bio-indicator for the sulfate-reducing bacteria was detected at 2 locations. The data indicated that sulfate-reducing bacterial activity dominated reductive dechlorination contributing to TCE removal at the site. Reductive dechlorination of TCE was enhanced following oxidant injection, which may be explained by one or more of the following mechanisms: (1) sodium persulfate injection directly enhancing sulfate-reducing bacterial growth by supplying sulfate, (2) oxidant injection providing simpler organic carbon for the bacteria by degrading naturally-occurring complex organic carbon in the aquifer, and (3) oxidant injection making VOCs more bioavailable by breaking down the sorption sites. | |||||||||
| Interesting Aspects or Significance of the Demonstration: | Unusual or Novel Aspects of Technology Design | |||||||||
| Other Interesting Aspects or Significance of the Demonstration: | Treatment of source zones (DNAPL) and treatment of recalcitrant compounds (VOCs, primarily TCE). | |||||||||
| Lessons Learned: | Reductive dechlorination of TCE was enhanced following oxidant injection. | |||||||||
| Vendor(s) or Consultant(s) Associated with the Demonstration: |
Xpert Design and Diagnostics (XDD) United Technologies Corporation University of Connecticut |
|||||||||
| Information Source(s) for the Demonstration: |
Enhanced Reductive Dechlorination Resulting from a Chemical Oxidation Pilot Test. Paper A-17, in: V.S. Magar and M.E.Kelley (Eds.), In Situ and On-Site Bioremediation - 2003. Proceedings of the Seventh International In Situ and On-Site Bioremediation Symposium (Orlando, Florida; June 2003). ISBN 1-57477-139-6, published by Battelle Press, Columbus, Ohio. http://www.battelle.org/bookstore# |
|||||||||
| Contact Information | ||||||||||
| Point(s) of Contact: |
Jaydeep M. Parikh Xpert Design and Diagnostics Stratham, New Hampshire, United States |
|||||||||
|
Edward X. Droste Xpert Design and Diagnostics Stratham, New Hampshire, United States |
||||||||||
|
Annette M. Lee Xpert Design and Diagnostics Stratham, New Hampshire, United States |
||||||||||
|
Paul M. Dinardo United Technologies Corporation Hartford, Connecticut, United States |
||||||||||
|
Bernard A. Woody United Technologies Corporation Hartford, Connecticut, United States |
||||||||||
|
George E. Hoag University of Connecticut Storrs, Connecticut, United States |
||||||||||
|
Pradeep V. Chheda University of Connecticut Storrs, Connecticut, United States |
||||||||||
|
Michael C. Marley (Primary Contact) Xpert Design and Diagnostics Stratham, New Hampshire, United States E-mail: marley@xdd-llc.com |
||||||||||
| | ||||||||||
