permitting class VI injection wells

October 16, 2023

deep injection wells
Stephanie Hill is a program co-leader for the SCS Carbon Sequestration and Deep Well Injection practice. She is a hydrogeologist and licensed Professional Geologist in multiple states, advising industrial clients on geologic storage options for carbon neutrality and disposal of industrial liquid residuals.


Injection well technologies have stored fluids and gases below protected drinking water aquifers for over half a century. When properly sited, designed, and operated, injection wells are a safe and responsible environmental management option for industries seeking permanent disposal of liquid and emission byproducts. Using two types of deep injection wells, some with environmental stewardship and federal tax credits available, SCS Engineers explains.

Hydrogeologist and licensed Professional Geologist Stephanie Hill provides a plain language overview of how EPA-approved injection wells work, a simplified graphic to show where injection wells are useful, and the associated costs and time to implement an operational system using Class I wells for deep injection of liquids and Class VI wells for sequestering carbon dioxide.

Byproducts include industrial wastewater or leachates, among others, and, importantly, sequestering carbon dioxide to reduce greenhouse gases. With the rise of transportation costs and water treatment plant restrictions, more industries seek certainty to support business and environmental longevity. Consequently, there is an increasing interest in using injection well systems to manage waste liquids and leachate. The operation of injection wells permanently sequesters industrial byproducts and is a federal and state-preferred technology to protect underground drinking water sources.

SCS Carbon Sequestration and Deep Well Injection team co-leader Stephanie Hill explains how operating an injection well system at your facility may help insulate your business from increasing disposal costs and serves as a responsible environmental management option.


Watch An Overview of Carbon Sequestration and Deep Well Injection for Industry.


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Posted by Diane Samuels at 6:00 am

August 1, 2022



Optimize Protection of USDWs – Minimize the Sitewide False Positive Rate


EPA permit requirements for Class VI injection wells explicitly include incorporating a Testing and Monitoring Plan to optimize protection of USDWs – Underground Sources of Drinking Water. The regulatory requirement is for periodic monitoring of groundwater quality above the confining zone that may result from injection fluid movement through the confining zone. Testing and monitoring plans usually implement an antidegradation strategy. Take sufficient background data to characterize the statistical distributions of groundwater quality parameters before operation. Then the same water quality parameters are sampled periodically during and after injection and compared to the background. Any statistically significant increases over the background are investigated as a possible result of injectate migration above the confining zone.

To make the detection monitoring program more robust, there is a tendency to increase the number of well/parameter pairs in the monitoring network. This is done by adding additional wells to decrease well spacing and by adding monitoring parameters to make sure that nothing gets missed. Paradoxically, this tendency decreases the statistical power of the groundwater monitoring network by increasing the sitewide false positive rate (i.e., the number of false positive detections increases, often to an unreasonable degree). Each apparent statistically significant increase involves a costly investigation with greatly increased complexity. In this talk, we examine the sitewide false positive rate for sitewide groundwater monitoring networks and its relationship to the number of well/parameter pairs and discuss how hydrologic and geochemical knowledge and characterization can be used to build a more robust and cost-effective groundwater monitoring plan that is protective of USDWs near Class VI injection wells.


To attend this live presentation, register for the upcoming National Carbon Capture Conference November 8-9 in Des Moines, Iowa. Visit SCS Engineers at booth 120. Meet Charles Hostetler.






Posted by Diane Samuels at 11:06 am