Disadvantages

• Too little iron in the sediments that form the aquifer will make it impossible to generate an effective treatment zone.
• Too much iron in the sediments may limit the size of the treatment zone or will require more chemical reagents to be injected.
• The plume must be well characterized and its extent in the aquifer well defined.
• ISRM poses health and safety concerns related to the handling of hazardous chemicals and the injection of fluids.
• Up gradient and down gradient monitoring wells are required to assess the effectiveness of plume remediation.
• Unspent chemical, buffers, and some contaminants mobilized by treatment are brought to the surface, which incurs disposal costs, treatment, or measures to protect human health.
• ISRM is not well suited for low-permeability aquifers.
• Application of the technology for remediation is not well documented and thus regulatory agencies may resist its use.

 

Question:

The state environmental protection agency is concerned about possible dithionite contamination of the aquifer after completion of the remediation. Considering the average groundwater velocity and the reaction of the dithionite solution with the iron in the aquifer, is it reasonable to conclude that all of the chemical will be recovered by pumping? What steps would you take to assess the possibility dithionite contamination, or is that necessary?