Column Treatability Studies

Column treatability studies are bench-scale laboratory tests that help evaluate remedial technologies under flowing conditions.

We are the leading provider of column studies, which are a critical step in the design of permeable reactive barriers and gravel bed reactors (GBRs) as well as a tool for understanding, designing, and combining other treatment technologies.

By simulating the impact of groundwater movement through an aquifer, SiREM’s column studies can help evaluate different remedial technologies under flowing conditions.

Column studies evaluate the following key parameters:

  • Degradation Half-lives: By measuring degradation half-lives of compounds of concern, one can assess breakdown products to rule out incomplete degradation along the treatment flow path.

  • Treatment-Zone Residence Time: By measuring concentrations along the column, one can understand the rate of treatment, which is a critical step in designing a treatment that achieves site-specific remedial goals.

  • Treatment Design Thickness: Using the residence time required for treatment and the expected groundwater-flow velocity, clients can arrive at the appropriate treatment design thickness for permeable reactive barriers.

  • Biological Processes: Column studies can compare intrinsic biological processes with enhanced bioremediation processes, including biostimulation and bioaugmentation.

  • Treatment Longevity: By understanding a site’s geochemical gradients, which indicate mineral precipitation and reactivity loss, one can assess the potential for passivation and fouling of zero-valent iron (ZVI) or sorptive media. Column studies can also help evaluate the longevity of low-solubility, slow-release amendments, such as potassium persulfate, calcium peroxide, or emulsified vegetable oil, as well as solid electron donors, including chitin, mulch, and compost.

  • Amendments and Injection Techniques: Column studies can be used to compare candidate amendments, such as ZVI materials, ZVI–sand mixtures, electron donors, and combinations of electron donors and ZVI materials. These studies can also simulate different injection techniques used to place the amendments.

ZVI Continuous-Flow Column Studies

Granular ZVI permeable reactive barriers are a proven technology to treat groundwater plumes containing chlorinated solvents. Our ZVI continuous-flow column studies, which typically last 1 to 2 months, simulate the movement of groundwater through a permeable reactive barrier. In addition, these studies can assess if ZVI promotes immobilization of metals such as arsenic and molybdenum.

Learn more about ISCR treatability studies >

Here is a column packed with ZVI to assess the treatment of arsenic. Groundwater is pumped through the bottom of the column in an upward flow and is sampled at different points along the ZVI bed to track the precipitation of arsenic. ZVI column studies can also be used to evaluate remediation of chlorinated volatile organic carbons (cVOCs), where the degradation of the cVOCs can be tracked along the column.

In this photo, columns are packed with Site geologic material and impacted with dense non-aqueous phase liquid (DNAPL). Groundwater is pumped up through the bottom of the column and mixed with surfactant and persulfate reagent through the bottom side ports to evaluate the washing and destruction of DNAPL from the Site geologic materials.

ISCO Continuous-Flow Column Studies

In situ chemical oxidation (ISCO) can be an effective remedy for many compounds of concern, including chlorinated solvents, petroleum hydrocarbon compounds, and other semivolatile organic compounds, as well as for nonaqueous-phase liquids (NAPL). ISCO column studies can be an effective tool to measure the longevity of slow-release oxidants and evaluate the impacts of surfactant washing on the effectiveness and speed of the remedy.

Most oxidant remedies are soluble in water and do not persist in the aquifer for extended periods. To optimize your remedy, ISCO continuous-flow column studies test the persistence of slow-release oxidants. For example, less soluble amendments, like potassium persulfate, can be mixed into aquifer materials to support the release of the oxidizing persulfate anions into groundwater over sustained periods.

Additionally, these studies can help you understand how slow-release oxidants can be further enhanced by adding surfactants, which can wash insoluble contaminants off aquifer material, allowing them to be more easily treated.

Learn more about ISCO treatability studies >

Bench-Scale Gravel Bed Reactor Continuous-Flow Column Studies

Gravel bed reactors (GBRs) are in-ground or surface structures that hold gravel. Groundwater is directed to flow into the GBR, where soluble amendments are added to support biofilms; these biofilms, in turn, remediate contaminants in the water.

SiREM’s GBR column studies are relatively inexpensive bench-scale experiments that simulate GBR performance under different conditions. These studies test different amendment substrates and influent conditions to develop systems, optimize performance, and estimate the longevity of GBRs.

Here are some flow-through gravel bed reactor mesocosms, packed with gravel and amended with soluble electron donors to stimulate the growth of selenium-reducing bacteria. The mesocosms are designed to test and optimize electron donor dosing for removal of selenium in groundwater.

In this photo, a biotreatability column is being used to investigate the biological reduction of selenate from groundwater with continuous injection of soluble electron donor through a site geologic material matrix.

Biotreatability Column Studies

Enhanced in situ bioremediation can effectively treat a variety of organic and inorganic contaminants. SiREM’s column studies can evaluate the persistence of slow-release electron donor amendments under flowing conditions and can simulate changes to the flow path over the remedy’s lifespan. In addition, our studies can evaluate biological remedies in conjunction with other technologies. For example, column studies can be used to understand anaerobic bioremediation with ZVI and aerobic bioremediation in the presence of hydrogen peroxide.

Learn more about biotreatability studies >

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Contact us to investigate your treatability options. Together we can create custom remediation solutions for your site.