In-Situ Chemical Oxidation Application of High pH Activated Persulfate at a Challenging DNAPL Contaminated Site
Presented on Monday, March 16, 2015
Rong Yuan1, Michael Hansen1, Robert Gan2 and Michael Fontana2, (1)Verina Consulting Group, LLC, Somerset, NJ, (2)VERINA Consulting Group, LLC, Somerset, NJ
Verina was retained to conduct remediation of a former chemical manufacturing site located in northern New Jersey. Groundwater has been impacted with chlorinated volatile organic compounds, including tetrachloroethene (PCE) and carbon tetrachloride and their daughter compounds along with base neutrals consisting primarily of hexachlorobutadiene (HCBD) and hexachloroethane (HCA). The dissolved groundwater plume and mobile and immobile DNAPL are found in two different hydrogeologic zones.
Based on a feasibility study, Verina proposed activated persulfate injection to restore groundwater quality beneath the site. A bench-scale treatability study and field pilot tests were conducted to optimize full-scale remediation design and to finalize the activator selection. The final remedial strategy includes DNAPL recovery followed by ISCO using high pH activated persulfate.
Given the size of the site, the multiple aquifer units impacted, and the complexity of the urban/developed setting, the full-scale remedy was planned to be implemented in four phases based on site constraint considerations. This will allow for “lessons learned” during the previous treatment phase to be applied in the more challenging areas. Additionally a customized injection trailer system was designed and constructed to provide flexibility to accommodate the current site usage.
Different densities of injection points were designed based on chemicals of concern (COC) concentrations observed in a given area. A higher density of injection points in DNAPL areas was implemented to provide greater mass in an effort to more effectively oxidize the COC.
Initial monitoring results revealed significant COC decreases in most monitoring wells where free-phase DNAPL was not identified.
This article discusses the challenges encountered, selection of remedial strategy and full-scale remediation design, innovative engineering planning and management to overcome the challenges, and a brief discussion of post-injection groundwater monitoring and data evaluation.
Rong Yuan
Verina Consulting Group, LLC, Somerset, NJ
Tammy Rong Yuan, PE, is an environmental engineer based in New Jersey. She has more than eight years of experience in site investigation, characterization, and remediation. She has been involved in various remediation projects in New York and New Jersey and has been taking a leading role in remedial strategies development, remedial alternative evaluation, and remedial system design. She obtained a master’s degree in Environmental Engineering from Stevens Institute of Technology, Hoboken, New Jersey, and received a bachelor’s degree in Environmental Engineering from East China University of Science and Technology, Shanghai, China.
Michael Hansen
Verina Consulting Group, LLC, Somerset, NJ
Michael Hansen, PE, is a senior engineer with more than 20 years of diverse experience in the areas of site evaluation, groundwater and soil remediation, environmental compliance, and the overall evaluation of potential liabilities-associated contaminated sites and other facilities. In addition, Hansen has extensive experience in project, program, and customer management for individual environmental projects as well as portfolios of projects/sites serving both private and public sector clients.
Robert Gan
VERINA Consulting Group, LLC, Somerset, NJ
Robert Gan, Ph.D., PE, has more than 27 years of professional experience in the civil and environmental engineering field. Areas of expertise include business management; leadership development; merger and acquisition support; marketing strategy development; environmental liability management; litigation support; water and wastewater characterization, treatment, discharge permit applications and engineering design; soil and groundwater remedial investigations/feasibility studies (RI/FS) and remedial design/remedial action (RD/RA); environmental and regulatory compliance assessment and audits; environmental support to property transaction activities; and air dispersion modeling, emission evaluation, and permit application. He earned his doctorate in civil and environmental engineering at the University of Wisconsin-Madison
Michael Fontana
VERINA Consulting Group, LLC, Somerset, NJ
Michael Fontana, LSRP, oversees technical studies and offers consulting services for soil and groundwater assessment, investigation, and remediation. He specializes in complex hazardous site investigation and remediation, underground storage tank (UST) investigations, litigation support, regulatory compliance, and the environmental aspects of real estate transactions.
