Understanding groundwater preferential pathways is a critical link in the development of conceptual site models and the design of groundwater remediation strategies. Identifying and mapping transmission zones that contaminants favor, or “preferential pathways,” is crucial when making decisions about how to best approach groundwater remediation at a site. Time and money can be saved by using technology to quickly gain a comprehensive picture of subsurface hydrogeologic conditions.
Hydraulic Profiling Tool (HPT) systems are an asset in gaining a detailed picture of the subsurface. Used with mobile drilling platforms, an HPT probe system can provide boring logs that make it easy to interpret subsurface soil characteristics.
Defining Compounds Found in Soil and Groundwater VOCs (volatile organic compounds) are legally defined, but generally are organic compounds that evaporate at low temperatures, typically room temperature or below. Because of their volatility, they are more mobile than many other compounds. The USEPA and other regulatory agencies set limits for many VOCS in air, soil and water.
SVOCs (semi-volatile organic compounds) are legally defined but have lower volatility and evaporate at higher temperatures than VOCs. Because of their lower volatility, they can remain in soil or water for long periods of time and accumulate more readily than VOCs. The USEPA and other regulatory agencies set limits for many SVOS in air, soil and water.
HPT Operation and Benefits An HPT system operates by applying water through a small opening on the side of the drilling probe as it is advanced through the subsurface. Water pressure and flow rate are monitored by the HPT logging system and displayed in real time. Sandy soils that contaminants favor and clays that affect groundwater flow are easily identified. Electrical conductivity logs can also be generated using the HPT system for an added parameter in interpreting subsurface conditions.
A Membrane Interface Probe (MIP) can operate in conjunction with an HPT, and is used to detect the presence of volatile organic compounds (VOCs) in real time and at accurate depths. An added benefit of HPT, electrical conductivity and MIP technology is their footprint. Nothing is removed from the subsurface which means investigation waste, along with the associated disposal costs, is nearly eliminated.
Case Study: Using HPT in the Field McFadden Engineering (MEI) utilized HPT boring logs to create stratigraphic cross sections to develop a conceptual model of groundwater flow at a large site near Mobile, Alabama. A product released into soil and groundwater at an industrial facility impacted groundwater quality over many acres. MEI was retained by the client to conduct a subsurface investigation and design an effective remediation strategy.
Preliminary site assessments revealed a very complex geologic lithology. Using HPT in conjunction with discrete groundwater sampling conducted at various depths, geologists and engineers at MEI identified preferential flow pathways for contaminated groundwater at the site. This information was used to construct two remediation systems designed to intercept, capture and treat contaminated groundwater prior to interacting with surface water in the area. Recovery wells were installed at depths that coincided with preferential pathways identified using HPT to efficiently target contaminated zones.
In teaming up with our industry partners and utilizing HPT and MIP technology, MEI can bring great value to clients that need quick assessment of subsurface conditions. By identifying and targeting groundwater preferential pathways, MEI can design effective remedial options tailored to specific site hydrogeologic and contaminant properties.
Hydrogeology is the study of groundwater distribution and movement over the ground surface and through soils and rocks. At McFadden Engineering (MEI), we have a team of professional Engineers and Geologists who specialize in hydrogeology. Contaminants that reach the soil frequently become a two-part problem as both the soil and the groundwater in the soil can be affected.
Groundwater, Surface Water and Groundwater Contamination
Groundwater is water (liquid or frozen) that has seeped below the earth’s surface and is stored in the spaces between soil or rock particles. An aquifer is created when a large amount of groundwater is stored in the same place. Groundwater flows through the soil or rock under the influence of gravity, usually on the order of a few inches to a few feet per year. Surface water is water (liquid or frozen) located above the surface of the ground, including stormwater runoff, streams, creeks, rivers, glaciers, ponds, lakes and oceans. Surface water usually flows more quickly than groundwater.
Soil and groundwater contamination impacts the public and the environment in many ways:
It can affect drinking water quality and can lead to health maladies associated with drinking contaminated water.
Contamination can devalue property and limit future uses for that property.
When buildings or residences are built on top of contaminated soil there may be a danger of vapors traveling up through foundations and into the air inside, where people may breathe in toxic compounds.
Natural habitats for wildlife may be lost in areas with contaminated soil and groundwater. This is particularly true for aquatic habitats.
Site Evaluation and Remediation Approach
When it comes to our hydrogeology expertise and working with clients, we evaluate the entire site including the soil, the groundwater, and the surface water to determine the extent of the problem our clients might be facing.
When it comes to site solutions, remediating the soil is usually the easiest option. If the area can be excavated, removing the impacted soil and disposing of the material is typically the quickest and cheapest option. However, when contamination is under a building or other structure, or it reaches the groundwater in the soil, the situation is often more complex. Furthermore, regulatory agencies are more sensitive to groundwater issues because groundwater is mobile and can travel off-site.
To tackle these challenges, we construct subsurface cross-sections and use groundwater modeling to develop hydraulic flow models for sites. These models help us predict groundwater flow direction and velocity, and indicate the best place to attack the issue with remediation systems. Using these tools and our experience in dealing with these issues, we can develop a cost-effective approach to cleaning up the site while meeting the regulatory requirements that may be present.
Timeline for Cleanup
Many variables can play a part in the timeframe for cleanup work. These can include:
Cost of remediating a site and how much funding is available to spend to solve the problem.
The chemical/physical nature of the contaminating chemical(s). For example, if the chemical dissolves easily in groundwater, it is easier to deal with than a chemical that separates itself from water (think oil/water).
The concentrations of the contaminants in soil or groundwater will affect how long it takes to remove them or break them down.
The response of time of state regulators is a big factor. It can take months to get approval from ADEM or another state’s regulatory agency to proceed with a remediation plan.
Best Management Practices
McFadden Engineering also specializes in designing Best Management Practices (BMPs) required at many sites. BMPs help minimize runoff that can ultimately allow contaminants to enter the surface water and groundwater. We can help keep clients in compliance by designing a Best Management Practices program, obtaining the necessary permits, and performing the required monitoring to help maintain compliance.
Our team has the personnel, tools and experience needed to help you develop a solution to solve your on-site challenges. If you have questions or are looking for project assistance, contact our team.
Some wastewater treatment facilities operate with an in-house facility management staff, but many other facilities do not have the resources to employ an experienced team to operate their wastewater treatment system. In these situations, it can be beneficial to consult with an environmental engineering firm with a certified wastewater treatment plant (WWTP) operator to develop optimized processes and recommendations to achieve regulatory compliance.
McFadden Engineering’s certified Grade IV Wastewater Treatment Plant Operator, Jimmy Wiggins, discusses the firm’s consultation process and benefits:
Q: What kind of wastewater treatment facilities often need assistance from a certified WWTP operator?
A: We do a lot of work with smaller and rural municipalities, water boards and other organizations that might have a facilities team, but not a dedicated wastewater treatment plant operator. Many times our clients employ an operator who doesn’t have much experience and works alone or with a very small team. We have worked with organizations of all sizes and operators of varying experience levels.
Q:When is the right time to reach out to a consulting engineering firm?
A: A process upset in the plant that cannot be resolved in house with routine corrective actions; a process is being altered or upgraded; compliance issues; applying for new discharge permits; new process equipment is being purchased and installed – each of these is a situation in which an experienced engineering firm can provide guidance. Sometimes all it takes is a sit-down discussion to answer questions, but other times an engineering firm can develop drawings, communicate with vendors, review equipment submittals and more to assist the in-house operator.
Q: What would be the first steps you would recommend to a non-compliant WWTP to help them recover?
A: The first step is to reach out to an environmental engineering firm with a certified WWTP Operator to perform a site assessment. A firm like this can make recommendations to help the plant reach recovery, which could range from mechanical and process control issues to laboratory procedures. A list of priorities can be developed to determine what issues to tackle first. Usually it starts by getting a handle on biological and lab data, then focusing on the mechanical components of the process. Additionally, recovery could include additional training for the facility’s operator and staff. It’s important to understand that when dealing with biological processes it can take time to make adjustments and corrections in order to see results.
Q: As an operator, what do you look for when initially assessing a treatment system?
A: As an operator, the first thing I want to evaluate is the lab data. This will give us a pretty good idea of how the plant is processing the wastewater. This includes monthly reporting to agencies and daily lab data if available. In addition, maintenance logs and equipment history are usually very helpful in evaluating issues. It’s important to observe the appearance and odor of the wastewater in all the processes. I also try to take a few hours with the senior operator on-site to walk through the entire process and ask questions.
Q: How important is an operation and maintenance program to the overall performance of a wastewater treatment facility?
A: Without a detailed and working maintenance program to guide the operator daily by outlining the mechanical needs within the plant, the operator could be set up for failure. All WWTP equipment should be maintained on a routine basis to add life and functionality. There are multiple free and low-cost software that can track these needs. It can be time consuming up front, but in the long run an ongoing maintenance program will allow the operator to have a better handle on equipment status, the treatment process, and avoiding issues later.
Q: What are some simple things owners can do to extend the life of mechanical equipment at a treatment plant?
A: Establish a user-friendly maintenance program using the equipment manufacturer recommendations. We recommend assigning one operator to take ownership and verify all maintenance is performed correctly, on time and that a record is kept of the activities. Routine maintenance is key, as is paying attention to the simple things – greasing bearings, checking belt tensions, changing oil and maintaining oil levels, etc. All these things can extend the life of equipment. Good housekeeping and keeping the facility clean and organized is just as important, too.
Q: What are some safety guidelines for treatment plants?
A: WWTPs can be dangerous if operators and staff are not trained properly. First, chemical training is important, as hazardous materials like chlorine and sulfur dioxide are commonly used and should be handled properly. Otherwise, it’s important to follow common sense. For instance, I always ask a new operator if they can swim. Additionally, any body of water should have a fence or barrier to prevent falls and life rings to prevent drowning. I also recommend operators employ the “buddy system” when possible. Always use the three-point rule when climbing stairs and ladders, and only allow certified personnel to work on electrical components. I also recommend that full safety training be performed by a certified trainer to all operators and staff. All training should be documented.
Q: What does McFadden Engineering offer when it comes to consulting on WWTP operations?
A: Our team of wastewater treatment experts have more than 100 years of combined experience and have been exposed to many issues and problems that individual facility operators likely have not encountered. We’re here to help operators as an ally – to solve unique problems and provide training to give them the comfort level to work confidently within their facility. We take pride in both problem solving and building operator confidence through training and expert guidance.
For more information about McFadden Engineering’s Facility Management and Operations services, click here or contact our team.
Beverly Lowery is a native of Biloxi, MS who fell in love with Mobile while obtaining her undergraduate degree in geology at The University of South Alabama. After graduating with her master’s degree in environmental science from The University of West Florida in August of 2018, she moved back to make Mobile her new home. She worked briefly at Energy Technical Services as an environmental lab technician before coming to work at McFadden Engineering. Before going back to school for her geology and environmental science degrees, she worked as an accountant for five years in Biloxi, Mississippi.
What led you to go back to school to study geology?
I had always wanted to be a geologist since I was a little girl. I started working when I was 14 and just naturally fell into the management and accounting field, but after getting my associates degree and working in the field for five years, I felt unsatisfied. I still longed to live out my dream of becoming a geologist, so I made the decision to go back and get my geology degree. I crave knowledge and enjoy learning, so going back to school to study what I love was an honor that I gave to myself. While obtaining my undergraduate degree, I became fascinated with researching natural ways to remediate polluted water. This led to me attending The University of West Florida where I got to research and create a water filter made out of biosolids biochar, while working at the university as an instructor and obtaining my graduate degree.
What attracted you to McFadden Engineering?
I first heard of McFadden Engineering when I attended a Partners for Environmental Progress breakfast that they sponsored. During this breakfast, McFadden Vice President Brad Newton got up to give a brief speech before the main guest went on. He talked about the company and their invention of the OxyShark® Water Reclamation System and when he went to sit down, I remember thinking “no wait, keep talking.”
Later a professor from UWF emailed me about an opening at the company and I knew I had to apply. I loved working at an analytical lab and testing water for various analytes, but I wanted to be part of the solution for improving water quality and eliminating excesses in these analytes that can be harmful to the environment. I felt that working for McFadden Engineering would allow me to use my skills and knowledge to better insure a safe and healthy environment.
What do you like most about being part of McFadden Engineering?
Honestly, everything, but mainly the people I work with. Being part of a great team that works together to solve environmental issues where everybody’s ideas and work comes together to form this wonderful solution, is incredible. I’m also learning a lot from everyone here and growing as an environmental geologist.
The Mobile Area Chamber named McFadden Engineering as the 2018 Innovator of the Year. OxyShark, a cost-effective wastewater treatment system has taken McFadden Engineering to the next level. “We wanted to develop a system that treated everything from domestic sewage to industrial strength wastewater in an efficient, reliable manner that was low in operation and maintenance costs,” said Frank McFadden, president and founder. Visit the Mobile Area Chamber’s latest issue Mobile Area Chamber Dec 2018- Jan2019.
Partners for Environmental Progress (PEP) recently asked Frank McFadden, P.E. to speak at a monthly lunch and learn event.
McFadden Engineering, INC is proud to be a PEP member and support their commitment to environmental responsibility.
Mr. McFadden spoke on the Alabama Department of Environmental Management’s (ADEM) expanding permit options for the discharge of treated wastewater. PEP members are embracing water reuse expansions in the state of Alabama. Click on the link to read about the PEP Lunch and Learn: Water Reclamation in Alabama.
Developing innovative water quality models and analyzing modeling results for private clients, municipalities and regulatory agencies are two of McFadden Engineering’s specialties. A leader in environmental water quality testing requires state-of-the-art in-house laboratory equipment.
There are many benefits to working with McFadden Engineering for water quality analysis. Here are four of them directly related to their in-house laboratory equipment.
Access to in-house laboratory equipment means results are available in a matter of hours, rather than days or longer. This capability allows McFadden Engineering to make recommendations on adjustments to wastewater treatment processes to maximize treatment efficiency and assist clients with compliance. Shorter wait times means faster analyses of issues related to treatment processes that enable McFadden Engineering to meet and exceed project deadlines.
Outsourcing laboratory results mean additional line items in a project’s budget. Let McFadden Engineering help streamline your project’s laboratory needs.
Field Sampling Capabilities
McFadden Engineering utilizes one of the industry’s lightest and most compact portable spectrophotometers that can perform a variety of water quality analyses using approved EPA methodology and verifiable accuracy using quality control standards.
Versatility and Customization
With McFadden Engineering’s equipment, clients gain access to a wide variety of analytical capabilities. From tests for metals, nutrients and other water quality parameters, the flexibility to customize testing requirements works to everyone’s advantage.
McFadden Engineering’s team of experienced engineers and geologists complement one another’s work to offer a holistic solution to solve even the most complex client project.
Get to know more about McFadden Engineering’s geologists in part two of this two-part blog series.
Matt Pastorcich – Staff Geologist:
McFadden Engineering’s staff geologist, Matt Pastorcich.
Matt Pastorcich joined McFadden Engineering in 2007 and will celebrate his 10th anniversary with the firm in October. He holds two bachelor degrees, one in geology and one in biology, from the University of South Alabama.
What led you to study and pursue geology?
My experience working in environmental testing got me interested in both hydrology and civil engineering. After working in the field for a major environmental laboratory, I decided to go back to college to pursue a degree that would lead to a professional certification. After studying engineering for a while, I became interested in the study of hydrogeology and contaminant hydrology. I switched my studies to geology with the goal of becoming a licensed geologist in the environmental consulting field.
What does a hydrogeologist do?
Geology is a diverse field of study. As a hydrogeologist, I interpret data from investigations of impacted groundwater sites to form an overall picture of what is going on below ground. In drawing meaningful conclusions based on the hydrogeology at a project site, we can make recommendations on the design of remediation efforts put into place at a site.
In my job, I write reports for clients that will be submitted to state regulators and make recommendations related to future actions at a project site. I also work in the field assisting with drilling, subsurface investigation, groundwater and surface water collection. Another task I am frequently engaged in is water quality investigation for wastewater treatment studies, in which I work closely with our engineers.
What is your favorite project or proudest moment that you have experienced in your role at McFadden Engineering?
My favorite project and my proudest moment took place as part of the same particular project site. The project was very challenging, involving hydrogeology, contaminant hydrology and innovative environmental engineering solutions. My proudest moment came when we completed the construction of our groundwater treatment systems at this particular site. It was the culmination of intensive investigation at the site.
What’s a common misconception about being geologist?
That you are a guy who looks like Indiana Jones who goes around the world with a pick axe cracking open rocks and studying them. That would be fun, though!
Marshall Eschete just celebrated his seventh anniversary with McFadden Engineering in September. He holds a bachelor’s degree in geology from the University of South Alabama and is a licensed professional geologist (P.G.) in Louisiana, Mississippi and Alabama.
What led you to study and pursue geology?
I have loved science since I was a kid and I like to work with my hands. Physics and astronomy are less hands on and I didn’t want to be a biologist. Geology was a natural fit.
How would you describe your role on the McFadden Engineering team?
As a geologist, I handle the subsurface portion of investigations. This includes soil, water or anything else we encounter. My work gives our engineers the information they need to design a remediation strategy or technology.
What does a typical day look like for you?
I spend a large portion of my time outside of the office managing and directing field crews and operations. The best part of field work is that I get to make the decisions about where and how far to dig or drill, but that doesn’t mean I can drill anywhere I want. I base my decisions on where and how deep we drill or dig with respect to budget constraints and project goals.
When I’m not in the field, I assist in writing reports that assemble the field data I’ve collected into a format that regulatory agencies and clients can understand.
What is your proudest moment at McFadden Engineering?
My proudest moment was when we closed the former Manufactured Gas Plant facility in downtown Mobile. It sat unused and locked up until we were brought into the project and through our efforts and the efforts of others, we were able to clean the property up and turn it into a beautifully landscaped public greenspace.
The property is in an area of town that badly needed a public park. It has been transformed from a fenced vacant lot to an open public area with walking trails, benches and play areas. It has transformed from an eyesore to a jewel of the community.
What is a common misconception about the field of geology?
Many people assume that all we do is drill oil wells. Geology is a very diverse field. You can study oil and gas, environmental issues, structural and engineering matters, mining, earthquakes, volcanoes and much more.