Frequently Asked Questions Regarding Treatability Studies

Are degradation rates/ trends observed in treatability studies representative of the field?

To the extent possible, treatability studies are designed to model aquifer conditions and replicate reaction rates observed in the field, nevertheless, the degradation rates observed in treatability studies are not always identical to that observed in the field.  
It is worth noting that, the relative degradation rates observed between treatments is often the most significant in terms of decision making. Furthermore, the error associated with treatability degradation half lives are often relatively small compared with errors associated with other groundwater parameters which can vary over orders of magnitude.        

How much Site material is typically required for a Treatability Study?

The amount of Site material required varies depending on the size of the proposed treatability study.  Typically 1 to 2 kg of aquifer solids from the target depths and 4 to 8 L of groundwater are required.

How long do treatability studies last?

Studies typically last 4 to 6 months, but may run up to 12 months if necessary.  Dechlorination assays are shorter in duration, lasting typically up to 12 weeks.

What are the different types of Biotreatability Studies?

Biotreatability studies include microcosm studies, column studies and dechlorination assays.  They can be anaerobic, aerobic, and incubated at different temperatures.   

What is a dechlorination assay?

A dechlorination assay is a modified microcosm study in which filter concentrated microorganisms are resuspended in either a enriched microbial media or site groundwater. Microbial concentration and the enriched media reduce the amount of time required to demonstrate dechlorination potential of indigenous microorganisms. Dechlorination assays provide rapid, sensitive and inexpensive measurement of dechlorination potential but are not designed to model in situ degradation rates.    

What data is provided by a treatability study?

Treatability studies provide degradation rates for target compounds, as well as monitoring  major anions, dissolved organic carbon measurements (if required),  dissolved hydrocarbon gases, and pH.   Data analysis includes evaluation of trends and calculation of observed target compound half lives.

How is treatability study data used?

Treatability data can be used to assess the applicability of alternate remediation technologies to specific site conditions, for example, bioremediation versus chemical oxidation, to answer field related design questions, such as, what is the most cost-effective electron donor?, the need for and effectiveness of bioaugmentation and how the site can be modified to optimize bioremediation, for example, through pH modification.    

When and where is treatability testing most advantageous?    

• Treatability testing has the most value at unique sites where remediation has not been demonstrated under similar conditions.
• Treatability testing is especially important at sites with a low threshold for negative impacts of remediation where it is important to rule out those impacts prior to field scale.
• Treatability testing is also advantageous to instill confidence where stakeholders may be unsure of a remediation technologies and at large sites where significant cost savings can be realized by use of lower cost alternatives.