Remediation of TCE-contaminated groundwater using KMnO4 oxidation: laboratory and field-scale studies

Abstract

The objectives of this study were to (1) conduct laboratory bench and column experiments to determine the oxidation kinetics and optimal operational parameters for trichloroethene (TCE)-contaminated groundwater remediation using potassium permanganate (KMnO) as oxidant and (2) to conduct a pilot-scale study to assess the efficiency of TCE remediation by KMnO oxidation. The controlling factors in laboratory studies included soil oxidant demand (SOD), molar ratios of KMnO to TCE, KMnO decay rate, and molar ratios of NaHPO to KMnO for manganese dioxide (MnO) production control. Results show that a significant amount of KMnO was depleted when it was added in a soil/water system due to the existence of natural soil organic matters. The presence of natural organic material in soils can exert a significant oxidant demand thereby reducing the amount of KMnO available for the destruction of TCE as well as the overall oxidation rate of TCE. Supplement of higher concentrations of KMnO is required in the soil systems with high SOD values. Higher KMnO application resulted in more significant H and subsequent pH drop. The addition of NaHPO could minimize the amount of produced MnO particles and prevent the clogging of soil pores, and TCE oxidation efficiency would not be affected by NaHPO. To obtain a complete TCE removal, the amount of KMnO used to oxidize TCE needs to be higher than the theoretical molar ratio of KMnO to TCE based on the stoichiometry equation. Relatively lower oxidation rates are obtained with lower initial TCE concentrations. The half-life of TCE decreased with increased KMnO concentrations. Results from the pilot-scale study indicate that a significant KMnO decay occurs after the injection due to the reaction of KMnO with soil organic matters, and thus, the amount of KMnO, which could be transported from the injection point to the downgradient area, would be low. The effective influence zone of the KMnO oxidation was limited to the KMnO injection area (within a 3-m radius zone). Migration of KMnO to farther downgradient area was limited due to the reaction of KMnO to natural organic matters. To retain a higher TCE removal efficiency, continuous supplement of high concentrations of KMnO is required. The findings would be useful in designing an in situ field-scale ISCO system for TCE-contaminated groundwater remediation using KMnO as the oxidant.

Comparison of Release Efficiencies for the Controlled-Release of Potassium Permanganate in Polycaprolactone

“…The present study focused on a CRBP system to measure the discharge of varied levels of KMnO 4 oxidant into aqueous systems. In the batch systems, dissolution of the PCL polymer releasing the KMnO 4 corresponded to what had been seen in other controlled-release systems [5] [23] [25] and, more specifically, with systems utilizing the same polymer oxidant system [20] [27]. As the amount of KMnO 4 in the PCL polymer pellets increased, a greater fraction of the oxidant was released as a function of time (Figure 2).…”

“…In situ chemical oxidation (ISCO) is one such remediation technology that has gained wide acceptance as a subsurface and groundwater treatment measure [1] [2] [3]. The purpose of chemical oxidation (or antioxidant) is to oxidize harmful chemicals in the environment to a less harmful level without inducing additional harm to surrounding areas and ecosystems or producing harmful by-products [4] [5]. ISCO oxidants generally include hydrogen peroxide, ozone, ferrate (VI), zero-valent iron and perhaps the most often used, permanganate [4] [6] [7] [8] [9].…”

“…Rate of controlled oxidant release is dependent on the type of encapsulation or binding agent employed. Common binding agents used for CRM formulations include paraffin wax, silica with clay, cement, and colloidal silica [4] [5]. More recently, several polymers have proven viable as a CRM mechanism when the goal for remediation is to allow treatment to be prolonged for a given operational [4] [15].…”

Urinary Malondialdehyde (MDA) and N-Acetyl-β-D-Glucosaminidase (NAG) Associated with Exposure to Trichloroethylene (TCE) in Underground Water

“…Thus, for those not working in industries that risk exposure to TCE but are still continuously exposed to polluted underground water through dermal exposure, it is possible to indicate that the past use of underground polluted water has contributed to adverse renal effects among residents. Therefore, it is crucial to immediately remediate TCE-contaminated groundwater under environmentally-related conditions using the continuous supplement of high concentrations of KMnO4 [32] and biomimetic iron-nitrogen-doped carbon [33].…”

Release efficiencies of potassium permanganate controlled-release biodegradable polymer (CRBP) pellets embedded in polyvinyl acetate (CRBP-PVAc) and polyethylene oxide (CRBP- PEO) for groundwater treatment

“…Potassium Permanganate (KMnO₄) has been widely used as a strong oxidant for the remediation of groundwater contaminated by chlorinated ethylenes such as trichloroethylene (TCE), perchloroethylene (PCE), Vinyl Chloride (VC), and dichloroethylene (DCE) [ [1] , [2] , [3] , [4] ] due to its relatively high stability, oxidation potential, diffusion in low permeability zones and cost-efficiency [ 5 ]. Studies have demonstrated that KMnO₄ can oxidize chlorinated ethylene compounds into both easily degradable and non-hazardous by-products such as hydrogen chloride, carbon dioxide, and organic acids through spontaneous cleavage of carbon-carbon bond [ 1 , [5] , [6] , [7] , [8] , [9] ].…”