Persulfates for soil and groundwater remediation

ELS® Microemulsion and ELS® Concentrate

ELS® is a lecithin-based substrate of food grade carbon used to enhance anaerobic bioremediation. ELS® is available as a 25% microemulsion or as a 100% concentrate.

By creating reducing conditions and serving as an electron donor for dechlorinating bacteria, ELS® promotes enhanced reductive dechlorination reactions. ELS® is delivered as a either a 25% microemulsion or a 100% concentrate, that is cold water soluble and can be applied via existing wells, hydraulic injection networks or direct push technology. Lecithin is composed primarily of phospholipids, which have both hydrophilic and hydrophobic regions in their molecular structure. As a result, ELS® can be expected to form a more stable emulsion compared to oils that are strictly hydrophobic compounds, making it easy to apply and handle.

KEY BENEFITS

  • Stimulation of biotic reductive dechlorination
  • Structurally bound nutrients phosphorous and nitrogen released to bacteria via the fermentation of the lecithin molecule
  • Forms stable emulsions
  • Easy to handle and cold water soluble

EXAMPLE CONTAMINANTS

  • Chlorinated solvents
  • Chlorobenzenes
  • Energetic compounds
  • Most pesticides
  • Haloalkanes
  • Nitrate compounds
  • Chromium

Key functions

  • Direct push injection
  • Gravity feed through existing wells
  • Low pressure injections
  • Recirculation systems

TECHNOLOGY: ENHANCED REDUCTIVE DECHLORINATION

Anaerobic bioremediation of chlorinated solvents involves the use of the contaminants as the terminal electron acceptor (respiratory substrate) i.e. instead of oxygen, nitrate, sulfate etc. This process could be enhanced by the addition of organic carbon, which serves as an electron donor. The addition of organic carbon to the subsurface will support the growth of indigenous heterotrophic bacteria in the groundwater environment. As the bacteria feed on the carbon, the bacteria consume dissolved oxygen and other electron acceptors, thereby reducing the redox potential in groundwater creating conditions favorable for reductive dechlorination to occur. Furthermore, as the bacteria ferment the organic carbon, they release a variety of volatile fatty acids (VFAs) such as lactic, propionic and butyric acids, which diffuse from the site of fermentation into the groundwater plume and serve as electron donors for other bacteria including dehalogenators and halorespiring species.

Technical overview and white papers

We give an overview of the different properties, mechanisms, and key attributes of our various reductive technologies that are applicable for a broad range of halogenated contaminants such as chlorobenzenes, chlorinated solvents, a number of pesticides, herbicides, haloalkanes and energetic compounds.

We present the results of emulsified lecithin-based substrates used as a reductive treatment of chlorinated solvents in groundwater. In situ chemical reduction and enhanced reductive dechlorination are cost effective remedial approaches for groundwater containing elevated concentrations of chlorinated solvents.

ELS® application guides

Mixing Guidelines to prepare diluted ELS® Microemulsion from a 25% concentration for injection.

ELS® webinars

Dan Leigh illustrates the basic principles of biologically mediated Enhanced Reductive Dechlorination (ERD). He explains the techniques used to set up the process and the problems that can be encountered. Using examples, he demonstrates the abiotic degradation pathway during biogeochemical degradation and ISCR. 

Brianna Desjardins and Brant Smith explain the lab-scale testing being conducted in our Environmental Solutions Laboratory for EHC® Reagent, ELS® Microemulsion, KLOZUR® persulfate, MetaFix® Reagent, and hydrogen peroxide. Lab-scale testing is required for the successful implementation of remediation technologies to prove a conceptual approach in a field trial.

We will present biological and in situ chemical processes, field comparisons of the biotic approach (ERD) to the ISCR approach, and show how ISCR improves biological processes in high sulfate aquifers.

Evonik’s laboratory created the KLOZUR® field test kit to provide a quick and reliable measurement of persulfate in the field.

There are two different kits available, depending on the activation method used. Each kit is capable of running ten tests and has a measurement range of 1g/L to 100g/L, with a theoretical accuracy of ±1g/L and ±2g/L respectively.

Contact and further information