Deep well injection can give electric utilities something that’s getting harder to find: long-term certainty. Where it’s suitable, it offers regulatory durability, operational flexibility, and a way to permanently store compatible liquids in deep geologic formations, away from surface resources and public exposure.
Utilities and independent power producers are under increasing pressure to manage complex liquid waste streams coming from power generation, air pollution control systems, and legacy infrastructure. CCR leachate, FGD wastewater, landfill leachate, and other industrial liquids are pushing the limits of traditional treatment and discharge options. Concurrently, regulations are tightening, treatment capacity is becoming constrained, and public scrutiny around wastewater management is growing.
At the upcoming 12th Annual CCR Workshop, SCSers Steven Freund and Kacey Garber share a practitioner’s perspective on how deep well injection can fit into a broader liquid management strategy. We’ll evaluate the feasibility of Class I injection systems, from waste characteristics and site conditions to the geologic setting, permitting strategy, and surface system design. We’ll also discuss the importance of aligning subsurface evaluation with pretreatment needs, operational flexibility, and long-term monitoring requirements.
From an owner’s point of view, deep well injection works best when it’s treated as strategic infrastructure, not just a compliance solution. Early integration into long-term planning can reduce cost uncertainty, decrease reliance on offsite disposal, and support changes in site conditions such as unit retirements, CCR closure activities, fuel changes, or water reuse initiatives. It can be especially valuable for facilities facing storage constraints, legacy waste challenges, or future regulatory risks.
We’ll also touch on how deep well injection can lower surface handling and transportation risks and help address community concerns tied to offsite discharge or downstream treatment. These benefits tend to matter most in areas with sensitive receiving waters, limited treatment capacity, or heightened public awareness.
We’ll conclude with lessons learned for utilities and regulators, including the value of early regulatory engagement, conservative geologic characterization, and planning for long-term operations and closure so owners can make informed decisions about long-term liquid waste management options.
Additional Resources:
Effluent Limitation Guidelines (ELGs) under the Clean Water Act set technology-based discharge standards for Steam Electric Power Generators. Recent regulatory updates and proposed deadline extensions have increased the complexity of achieving compliance for flue gas desulfurization (FGD), bottom ash (BA), combustion residual leachate (CRL), and legacy wastewaters. These changes in the regulatory landscape have prompted generators to evaluate alternative technologies to achieve compliance in a cost-effective and timely manner.
Deep well injection, regulated under the EPA’s Underground Injection Control (UIC) program, offers a potential solution for wastewater disposal by removing and isolating wastewater from the surface hydrologic cycle. Groundwater protection is assured through rigorous demonstration of geologic containment and well construction standards. However, there are additional operational considerations for deep well injection, particularly for pretreatment design.
Pretreatment design bases are directed towards maintaining the deep well’s operability and injectivity. Geochemical modeling is essential for identifying and defining mineral scaling and corrosion potentials in the subsurface, thereby establishing pretreatment design targets. Process design modeling can then optimize flowsheets that evaluate potential solutions towards achieving the pretreatment design targets.
Learn more at The World of Coal Ash (WOCA) 2026, May 4 – May 7
The World of Coal Ash – affectionately called WOCA – is the premier international conference on the science, application, and sustainability of coal combustion products. WOCA is hosted by the American Coal Ash Association (ACAA) and the University of Kentucky Center for Applied Energy Research (UK CAER).
Our Author, John Yang, will present a session titled “Managing Pretreatment Design, Injectivity, and Cost Through Modeling.” In his presentation, SCS will detail the workflow for establishing pretreatment design basis for two representative scenarios – a sulfate-rich contact water and an FGD wastewater currently undergoing heavy metal removal for indirect discharge. Jon discusses the geochemical basis for selecting pretreatment operations and high-level budgetary considerations. A combined geochemical and process modeling approach for deep well injection helps operators with vetting all potential options for achieving ELG compliance.
Jon Yang, PhD, is an engineering-focused geochemist with extensive experience serving industries for critical minerals and rare earth elements, industrial wastewater management, contamination, carbon capture and sequestration, and environmental services. He holds a Doctorate in Ocean, Earth, and Atmospheric Science from Oregon State University and a Bachelor of Science in Chemical Engineering from the University of Arizona. Dr. Yang’s background combines fundamental geoscience with applied engineering and has broad applicability to service areas such as deep-well injection, electric utilities, mining, and wastewater treatment.
Dr. Yang has previously led critical mineral and rare-earth element (REE) resource assessments at the National Energy Technology Laboratory for unconventional geologic feedstocks, including coal-related materials, shale, and ultramafic rocks. His experience includes advanced geochemical modeling of extractive processes, detailed lithologic and geochemical evaluation of core samples, and interpretation of depth-dependent compositional changes. He has designed and advanced novel extraction and geochemical process workflows, contributing to patented technologies and federally funded research programs designed to further the critical mineral supply chain in the U.S. Dr. Yang’s work has advanced research from early technology readiness levels along pathways for potential commercialization and/or technological transfer. He has served in professional capacities, providing technological due diligence on emerging technologies.
Thursday, February 12
Class VI UIC Session
8:30 AM – 10:00 AM
Injecting supercritical carbon dioxide increases pressure within the injection zone. If an improperly plugged borehole that penetrates the confining zone is near the injection site, an increase in pressure could induce formation fluid to flow upward through that borehole from the injection zone. Upward flow of fluid in the borehole could carry dissolved constituents, potentially endangering underground drinking water sources. The pressure at which this would occur is called the threshold pressure, a key factor in delineating the Area of Review for a Class VI Permit Application.
The EPA Class VI Guidance approach to calculate threshold pressure is conceptually flawed and has proven difficult to implement. The approach in the guidance does not consider typical project time scales and ignores important physical processes. EPA is currently reviewing the details of this approach and considering revisions to the guidance.
In this work, SCS can identify the geologic conditions under which the equilibrium approach grossly underestimates the critical pressure, as well as the operational details that affect pressure buildup in the injection zone over time. SCS can identify conditions under which the equilibrium approach is not appropriate for evaluating the critical pressure, and we establish a kinetic framework for its evaluation.
This kinetic approach, using time-based single-phase computational modeling, is less complicated than the multiphase flow modeling already required by the Class VI regulations and is equally capable of calibration, monitoring, testing, and reevaluation during the operational phase of a Class VI project.
Tara Gross, Project Advisor, SCS Engineers
Ms. Gross is a Project Advisor on the Deep Well Initiative team. She is a geologist with over 20 years of experience in oil and gas (O&G), land-use permitting, subsurface mapping, and compliance. Project experience includes support developing Class I, II, and VI Underground Injection Control (UIC) applications, oil production plans, midstream O&G pipeline permitting, surface and groundwater compliance, subsidence evaluation, critical minerals, carbon capture, utilization, and storage (CCUS), produced water, seismicity, lithium extraction, environmental studies, Department of Energy grant programs such as CarbonSAFE and CarbonBASE, and CEQA analysis.
Join Tara at the Class VI UIC Session
February 12, 2026
8:30 am – 10:00 am
Tara will present Advancing Class VI Permitting: A Lessons Learned Approach to Critical Pressure Modeling and Impact Analysis at 9:30 am.
This blog addresses a salient question among the plethora of questions asked and answered during the feasibility phase of a Class I Underground Injection Control (UIC) well. State agencies, the US Environmental Protection Agency, and other government bodies worldwide approve permits for energy, industrial, and waste management developers eager to permanently and safely inject hazardous and non-hazardous wastes into deep, confined rock formations. As environmental engineers and geologists, we plan all classes of injection wells to manage risks, navigate technical challenges, and meet regulatory requirements.
How much liquid can we inject into a UIC well?
This question is in everyone’s mind when we talk to clients about the feasibility of using a Class I injection well to manage their liquid wastes. Once we have decided that the answer is greater than zero, we have to quantify that rate and volume to see if a Class I well (or multiple wells) may meet their liquid management needs by considering other feasibility requirements.
There are many considerations when determining what injection rate is suitable for a facility, such as peak and average flows from operational or seasonal variations, stored liquids to drain down, facility planning (expansions or closure), and optionally accepting off-site wastes. The governing factor that dictates what injection rate is achievable is the geology.
Without data from a nearby operating injection well, there will be some uncertainty about what injection rate may be achievable until you drill a well. There are methods to calculate an estimated injection rate to inform decision-making and support permitting. The same principles to calculate an oil well’s theoretical production rate can help estimate the Class I well’s injection rate.
Applying Darcy’s law to the ideal well model produces an inflow performance relationship shown below:
Where:
Does it work?
Let’s take an example with known reservoir parameters, pressures, and injection rate and see if we can estimate the actual injection rate. The following terms come from operational testing of a Class I well in southern Illinois:
So, how close is the UIC calculated injection rate to the actual injection rate?
The injection rate during a recent fall-off test at these conditions was 371 gpm or 115% of the calculated injection rate of 322 gpm, a useful approximation for evaluation feasibility.
Data from a nearby well and site-specific reservoir data are best when calculating an estimated injection rate. If data from a nearby well is unavailable, use legacy oil and gas data such as geophysical logs, drill stem tests, and core data to develop parameters for the calculation. The more data available and the closer to the proposed site that data is, the more accurate the estimated injection rate will be.
To evaluate the feasibility of a proposed well, pR may be obtained from nearby drill stem test data and may be calculated based on fracture pressure. Calculate a conservative estimate of fracture pressure using the minimum calculation of the Hubbert and Willis Method. The difference between the calculated fracture pressure and pR is the pressure increase that can occur before fractures may be induced. Multiplying the difference by 0.8 will give a conservative estimate of Pwf.
Additional consideration should be given to the total volume of liquids injected by performing pressure build-up calculations over the proposed injection lifetime to confirm the non-exceedance of the fracture pressure.
There are many considerations when evaluating the feasibility of operating a Class I well. When our clients determine if a well or multiple wells can support their liquid management needs, an estimated injection rate is one important criterion that informs that decision.
Additional UIC Well Resources:
About the Author: Senior Project Professional, Jacob (Jake) Dyson
As a Professional Geologist Jake Dyson is responsible for the permitting, drilling, regulatory compliance and operation of Class I, II, V, and VI UIC wells. Dyson manages permitting, testing, and workovers of UIC wells and serves his clients as a technical advisor on developing and executing well construction material, formation fluid, and well testing programs including managing drilling and construction cost, interpreting geologic data for model inputs and developing static geologic models.
Join SCS Engineers at the 2024 PWS Permian Basin Summit. The Produced Water Society brings together industry-leading speakers such as Neil Nowak to address the produced water issues faced by operators, water midstream companies, and water service providers.
Neil will present “Produced Water Recycling and Evaporation Facilities” as a Roundtable Presentation at the event.
August 13, 2024
2:00 – 3:15 PM
Produced water experts with Permian Basin experience will discuss the existing solutions, technological innovations, and produced water management best practices needed to keep the most productive unconventional shale play in the world pumping hydrocarbons while ensuring sustainable business operations and safeguarding the local environment and freshwater resources.
Join SCS Engineers to solve environmental challenges.
• Carbon Sequestration & Deep Well Injection
• Greenhouse Gas Services
• Oil and Gas Services
Meet with SCS Engineers at the 2024 Railroad Commission (RRC) of Texas Regulatory Conference July 30-31 at the AT&T Hotel and Conference Center to inform the oil and gas sector on the applicable laws, rules, and procedures for hydrocarbon production in Texas.
Join SCS Engineers to solve future energy challenges like:
Since the 1980s, the USEPA and state regulatory agencies have made great strides to regulate wells and have a robust list of requirements that industrial, municipal, commercial, and manufacturing applicants must adhere to for installing and operating a deep injection well.
Despite the regulations, many communities fear injection wells, and who can blame them? Cutting through the misinformation and online “studies” makes understanding the facts and science difficult. The myriad of groundwater concerns making headlines can become overwhelming. This video, by our team of environmental and injection well experts, takes you through the critical elements and regulations when considering injection wells. And how they help create a safe well site acceptable to regulatory authorities, communities, and industry.
Our presenter is Kokil Bansal, a licensed professional engineer with experience in landfill redevelopment site assessments, geologic sequestration, wastewater permitting, and advising her clients on proven sustainability practices. She holds a Bachelor’s in Chemical Engineering and a Master’s in Environmental Engineering. Ms. Bansal works on the SCS Engineers’ team of licensed engineers, geologists, hydrogeologists, and scientists dedicated to safe and sustainable environmental solutions for industry.
Ms. Bansal reviews the significance of the following factors for a USEPA “safe” deep injection well:
Number one is proactive engagement; it is critical to talk to all stakeholders, including community organizations, the public, and local environmental advocacy groups, about the well installation plan covering the ‘how and where.’ Early involvement in the process leads to a better understanding of the benefits and factors you, as an applicant and local business, are implementing for the public. ~ Kokil Bansal
Additional Resources
SCS Engineers’ deep well injection expert, Monte Markley, is presenting at the 26th Annual EUEC conference, February 13-15, 2024, at the Irving Convention Center near Dallas, Texas.
The Energy Utility Environmental Conference (EUEC) attracts some 2000 attendees from around the globe and features over 300 speakers and 200 exhibitors. This is the first live in-person event since the pandemic, and we are happy to be together again!
Visit the EUEC 2024 website for abstract info, conference details, and registration information.
We hope to see you there!
Meet SCS Engineers’ carbon sequestration and deep well injection experts at BOOTH 729 at the 39th annual International Fuel Ethanol Workshop (FEW) & Expo, June 12-14, in Omaha, Nebraska.
The FEW provides cutting-edge content and unparalleled networking opportunities to the global ethanol industry within a dynamic business-to-business environment. It is the largest, longest running ethanol conference in the world—and is powered by Ethanol Producer Magazine.
The FEW delivers timely presentations with a strong focus on commercial-scale ethanol production – from quality control and yield maximization to regulatory compliance and fiscal management. The FEW is also the ethanol industry’s premier forum for unveiling new technologies and research findings. The program extensively covers cellulosic ethanol while remaining committed to optimizing existing grain ethanol operations.
Abstract: Carbon Capture and Storage (CCS) is becoming increasingly attractive due to growing climate change concerns as well as tax incentives related to conducting CO2 capture. Facilities that capture CO2 may consider storing captured CO2 via geologic sequestration (GS). GS at a given location requires a Class VI Underground Injection Control (UIC) permit for a Class VI UIC well(s) to inject supercritical CO2. These permits require multiphase flow modeling to delineate both the extent of the supercritical CO2 plume and areas that exceed a critical pressure threshold as a result of injection. We have found numerical modeling is also valuable during project scoping to provide a sense of what the total CO2 storage capacity may be for a given project. To determine long-term storage capacity, CO2 trapping (storage) mechanisms must be considered, including structural/stratigraphic, capillary, solution, and mineral trapping (depending on geochemistry). Solubility trapping appears to be the ultimate trapping mechanism for injected CO2 under most geochemical conditions; therefore, solution storage efficiency will be a key metric for project scoping. Solubility trapping occurs when the CO2 dissolves from its separate, buoyant phase into formation pore water. If the total available pore space for the project and the solubility limit of CO2 can be estimated, then the total solution storage capacity can also be estimated. Then numerical modeling can be used to estimate design and operational parameters to quickly examine under what conditions the most efficient use of pore space occurs. In this example, we investigated what factors may promote solution storage efficiency using a multiphase flow model. This includes how supercritical CO2 injection rate, duration, and location(s) affect solution storage efficiency. This simplified study concluded that injection rate, duration, and location(s) all affect solution storage efficiency. Project-specific considerations need to be incorporated into the model in order to determine the conditions ideal for maximizing solution storage efficiency.
The 2023 FEW program has four concurrent tracks and three additional events:
The FEW typically draws industry professionals from all 50 states and more than 30 countries. Upwards of 550 biofuels producers from 209 facilities all over the world attend each year.
The 2023 FEW proudly visits Omaha, NE. We look forward to seeing you there!
Click for more information as speakers and topics are announced. Early Bird Registration ends May 3.
Glenn Haave has had a close relationship with protecting our environment for years, ever since his days working on the ocean towing ships in and out of ports. He figured his deep appreciation of his natural surroundings and desire to protect them might carry into his chosen career path, especially after earning a Bachelor of Science in Geology. But when he came to SCS Engineers as a high-spirited, new graduate, he had no idea of the opportunities that would come his way— both at SCS and serving in the U.S. Coast Guard Reserves.
“Both SCS and the Coast Guard hold you accountable to rise to the occasion and get the job done. With that trust and delegation of responsibilities, I am challenged to become a leader, which gives me a sense of duty and confidence,” Haave says.
Combining Geology, Hands-On Experience, and Teamwork
Starting at SCS doing groundwater and soil sampling and helping remediate landfills for redevelopment, Haave proved to be a fast learner. Quickly building on his skills, he was presented with a unique proposition– to join one of only a few multidisciplinary teams in the country that design and install deep well injection infrastructure. EPA-approved injection wells are safe for placing fluids underground into porous geologic formations. These underground formations may range from deep sandstone or limestone to a shallow soil layer. Injected fluids may include water, wastewater, brine (salt water), or water mixed with chemicals.
Planning, permitting, and executing these projects is a multifaceted undertaking encompassing geologic consulting, reservoir engineering, and deep drilling, with environmental protections and sustainability as core goals.
“Few geologists ever get to work on this type of job. These projects require a lot of capital, time, and very specialized expertise. I was fortunate to be working at SCS’s Miami office at the right time, able, and willing,” says Haave, drawn to complex tasks calling for a razor-sharp eye for detail, focus, and discipline.
Drawing on his experience supporting the Miami-Dade Water and Sewer Department Ocean Outfall Legislation Injection Well Program, where he saw 11 wells constructed in a demanding, high-profile project, he is now on a multidisciplinary team of SCS professionals.
Innovations in Carbon Sequestration – Protecting Our Environment
Now, he takes on a new charge: working on a type of deep injection well called a Class VI well. This sophisticated infrastructure directs carbon dioxide (CO2) liquids and gases into the ground for long-term storage. A fairly new, EPA-approved carbon sequestration technique, it is proven effective at substantially reducing CO2 emissions to the atmosphere.
“Class VI wells are an exciting evolution as the world looks to decarbonize the economy. I feel like I am part of an extraordinarily innovative solution where I am using my background to support a global effort to impact our climate positively,” Haave says.
“I feel a sense of purpose in that we are helping mitigate exponential global warming. At least as important, I am comforted that what we do brings hope that my son, daughter, and their generation will grow up on a healthy, safe planet.”
Another Dimension – U.S. Coast Guard A School
As he embraces this unique opportunity to help the environment, he celebrates another milestone: graduating from U.S. Coast Guard A School and advancing in rank to Marine Science Technician Petty Officer Third Class. His calling will be responding to pollution incidents to protect U.S. waters and inspecting facilities and container vessels that transfer hazardous materials to and from land.
Getting into the Reserves is not easy, nor are the next steps. Making it into A school after boot camp is typically a two-year journey: the waiting list of accomplished graduates is long.
Haave finished three intensive months of classroom work; mock training in the field, morale-building exercises to keep spirits high while away from family and friends, and a battery of testing.
Through these rigorous trials, he took on the honorary role of Master at Arms, leading and mentoring his shipmates and serving as a liaison between the crew and captain.
“Becoming a Coast Guardsman was like a dream come true. It was something I had wanted to do since I was 19. But I needed time to mature. I did a lot of soul searching before I could fully realize what was entailed in living up to Coast Guard expectations; to truly embrace that it’s about a sense of duty to country and family, and to deliver on that conviction,” says Haave, now 37, and nominated as a most inspirational person by his shipmates and instructors.
When he shared his long-envisioned, materialized aspiration with his SCS supervisors, he was unsure what they would think; he was taking on another big commitment.
“They were not only accommodating, but they are proud. SCS Engineers is a military-friendly organization. They are always supportive, flexible, and believe in me.”
In the Coast Guard, he had a choice from a far-encompassing list of specialty areas, given his high military school entrance score. He chose marine science technology because it tied in with his civilian work – navigating and ensuring adherence to federal regulations and being a steward of the environment.
Looking Forward
Gazing back at how far he’s advanced in just the last few years, then looking forward, Haave says, “You know, I’m just 37 years old. I feel like I have a lot more in my gas tank –the amazing experiences I have been fortunate to have are just the beginning. I see more opportunities to advance as a leader and to become an even more rounded geologist, able to approach every project comprehensively and deeply.”
We thank all of our veterans and appreciate Glenn Haave for his service to the U.S. Coast Guard and his commitment to protecting our environment with SCS Engineers by advancing sustainable environmental practices and solutions.
Find out more about carbon sequestration and greenhouse gases:
Video: Building a Well
Information: Deep Well Injection and Sequestration Wells
Video: Carbon Sequestration for Landfills and GHG Tutorial
Safe engineering takes discipline and teamwork –qualities that have always served SCS and our clients with innovative, proven solutions for running operations more efficiently and greener. For a rewarding career, consider SCS Engineers, where all employee-owners have a vested interest in every solution.
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