Here at SCS, we work for developers, industry, and manufacturers to help them run cleaner, safer, and more efficiently. This PBS video provides insight into how SCS brings value to the waste industry, our clients, and, most importantly, our communities.
You may ask yourself, don’t pig farms create pollution? Yes, but even that waste is reusable!
Did you know the food you buy in the grocery is supported by our environmental experts? Learn more about SCS’s environmental engineers and consultants who bring contaminated properties back to life, lower and capture greenhouse gases for fuels and renewable energy, and make possible a brighter future.
If you are interested in becoming an SCS Engineers employee-owner, watch our comprehensive video to see the breadth of services our teams offer.
The main thoroughfare in Madison, Wisconsin, leading to the state capitol, is going through a major renaissance. Once an idle brownfield, and before that an active industrial-commercial area, the entire block has now been converted to residential, commercial, and office spaces, as well as a youth art center. After extensive due diligence to assess, then successfully remediate significant adverse environmental conditions from past uses, the property’s new mixed-use buildings are open for occupancy. The community art center opens in 2021.
The block formerly housed a dairy operation, gas station, auto maintenance shops, a print shop, and a dry cleaner. These past uses and the historic fill placed on the property resulted in chlorinated solvents, petroleum, polycyclic aromatic hydrocarbons (PAHs), and heavy metal contamination.
Remediating and mitigating environmental contamination and redeveloping brownfields like this one into vibrant, revenue-generating community assets takes pooled expertise from multiple disciplines, including hydrogeology and environmental engineering.
While these projects can provide high value for communities long into the future, they are complex and require large investments up front, explains Ray Tierney, an SCS vice president. Having a team that gets a full picture of the property’s environmental condition, knows regulators’ expectations, and can identify technically sound, cost-effective remediation and mitigation approaches can translate to substantial money savings.
In this case, a solid knowledge base and vetting key details resulted in seven-digit figure savings and facilitated prized redevelopments.
“We identified the amount of soil and groundwater contamination, evaluated strategies to best address the issues, and came up with a cost estimate for remediation. Based on the estimate, along with documentation validating the scientific rationale for our recommendations, the seller reduced their price to account for the legacy environmental liabilities which the purchaser agreed to accept and address as part of the property’s redevelopment.”
SCS Engineers assessed for contamination; oversaw the management of contaminated soil and groundwater during construction according to the materials management plan; supported the client in securing grants, permits and documented compliance with the approved planning documents.
For this project, as is often true in historic urban areas, the greatest expense was dealing with widespread contamination found in the historic fill soils and with groundwater issues.
“Our client is obligated to handle contaminated materials properly. We plan and permit the proper procedures, work with contractors to facilitate the work, documenting that procedures and plans are followed while making sure they only invest what is necessary to be judicious in protecting the environment and public health,” says the SCS Project Manager and Geologist Dr. Betty Socha.
During construction, Socha’s team was onsite to assist contractors in complying with environmental plans and permits, documenting that activities were completed safely and in compliance with Wisconsin Department of Natural Resources (WDNR) expectations. The team oversaw soil removal and management during site demolition and construction of the foundation, including piles and a structural slab. This support system reduces the geotechnical requirement of the underlying soils to reuse more onsite soil safely. But knowing what soil is acceptable and orchestrating the separation of contaminated and non-contaminated materials takes specialized expertise and skill.
“During construction, we evaluate soil conditions, so contaminated soil is safely disposed of at a landfill. But landfilling large volumes of soil is a considerable expense, so it’s important to determine what is safe to be segregated as clean soils for reuse elsewhere. Knowing how to do this efficiently will minimize disposal costs and maximize the use of valued resources,” Socha says.
Getting a handle on groundwater conditions and identifying the best management strategy requires equal attention.
“This property sits on a strip of land (an Isthmus) between two large and prized lakes, with a shallow water table. We thoroughly assessed the groundwater (aka, hydrogeologic) site conditions and managed groundwater generated during construction and dewatering activities,” says Tierney.
“We documented the extent of contamination, and the WDNR confirmed our evaluation that no additional remedial groundwater treatment systems were needed. We could show the contamination was contained enough to pose no risk to municipal wells, private wells, surface water, or other sensitive environments. However, the client still needed a permit to dispose of the contaminated groundwater generated during dewatering for construction of the building foundation and underground utilities,” says Tierney.
Major brownfield redevelopment projects are involved with multistep processes. They begin with a Phase I Environmental Assessment entailing an inspection of the property and a historical review.
That’s where SCS initially identifies potential or existing environmental liabilities from contamination. Then the team confirms the presence of multiple soil and groundwater contaminants through a Phase II Assessment, involving collecting and analyzing soil and groundwater samples.
Next comes a site investigation, a robust testing program to see exactly what is going on. This is where the team further defines contamination, locations, how far it spread, and concentrations. That information lays the groundwork for developing the remedial action plan to file with the WDNR. The team then works with the redevelopment contractors to seamlessly and concurrently manage both the property’s remediation and the buildings’ construction.
In Madison, Socha, Tierney, and their team also helped the developer apply for and win a $500,000 brownfield grant from the Wisconsin Economic Development Corporation, a practice that is as much an art as a science. Additional public support for the project was also received through tax incremental financing (TIF) and the Wisconsin Housing and Economic Development Authority (WHEDA) tax credits for low‐income housing.
“We merge our technical backgrounds to show the land has the potential to be turned into a strong asset that addresses the legacy environmental contamination, promotes public health, and delivers a high-value property that pays taxes and supports important city services,” says Tierney.
It takes technical horsepower to show regulators just how you are addressing contamination. You need to show the economic development group awarding the grant that the project will create well-paid jobs and tax revenue. Equally important, it must be shown that the redevelopment helps address a community need for affordable workforce housing and additional market-based housing,” Tierney says.
Tenants have already moved into the two 11-story mixed-use buildings. In addition, The Madison Youth Arts Center (MYAC) is slated to open in early summer, with a grand opening ceremony this fall. The MYAC includes classrooms, offices, rehearsal spaces, and a 300-seat auditorium.
The final project showcases the heartbeat of this popular downtown space situated between two large lakes, with features such as a rooftop terrace, plazas with seating and green space, and soon to come are 3D urban art installations and murals that tell the story of this long-lived community.
“The redevelopment of brownfields and the creation of projects like the Lyric and the Arden align with the City of Madison’s Performance Excellence Framework Vision of Our Madison – Inclusive, Innovate, and Thriving. These types of redevelopment projects help the City act as a responsible steward of our natural, economic, and fiscal resources. While making efficient use of land and cleaning up brownfields, the City is able to provide workforce housing, job opportunities, and cultural venues, all while enhancing the City’s tax base,” says Dan Rolfs, the Community Development Project Manager for the City of Madison’s Office of Real Estate Services – Economic Development Division.
It takes a village, or in this case – a City, to revitalize an urban brownfield!
Brownfields Resources to Organize, Educate, and Implement Plans in Your Community
If you thrive in a friendly, collaborative, and client-focused company, SCS Engineers is the place for you. We’re looking for field technicians to work collaboratively on our Field Services teams nationwide. Specific information is posted for each open position. Use our job search to find your desired location.
Under general supervision, our technicians operate, monitor, and maintain gas migration control and recovery systems, including gas well monitoring and adjustment, troubleshooting, and system repairs.
Become one of the engineers, consultants, scientists, and technicians that help private and public entities run cleaner and more efficiently. A very rewarding place to have a career!
A Nebraska city earned an $800,000 grant from the Environmental Protection Agency. The City of Lincoln plans to use the grant to assess and clean up brownfield sites, including up to 10 acres of land city officials hope to use for self-sustaining urban agriculture projects.
Officials plan to create a self-sustaining urban agricultural area in two adjacent 5-acre parcels for lease by local farmers. Lincoln can begin moving local food production into commercial use by local businesses.
In a recent Journal Star article, Tim Rinne, chairman of the Lincoln-Lancaster County Food Policy Council, said, “Rather than continuing to rely exclusively on drought-stricken and wildfire-plagued California to produce the bulk of our produce, or waiting for the next breakdown of our national food distribution network like we saw with the COVID-19 crisis, Lincoln’s city government leadership is taking the visionary and cautionary step of building a resilient local food system.”
The planned agricultural use also helps protect surrounding developments. The five-year grant will help the city assess four other sites in the area and could support cleanup plans at two more sites.
Brownfields Resources to Organize, Educate, and Implement Plans in Your Community
Among the extensive list of landfill operating costs are those incurred for landscaping to keep the slopes trimmed. While regularly mowing large spaces is expensive, keeping sites well-groomed is essential for protecting landfill covers and providing other safeguards. Putting sheep and other grazing livestock to work eliminating invasive plants and other vegetation from properties difficult to traverse for two-legged workers could be a good alternative. Grazing is an often useful technique for maintaining traditional native plants while reducing weeds and unwanted vegetation, mitigating risk for growth to dry out and possibly catch fire or intrude on a site’s pipelines and infrastructure.
In municipal solid waste landfills near urban areas, such as in Pennsylvania, Arizona, and California, grazing animals are helping with slope management. These locations also reap environmental benefits of reduced soil erosion; improved air and water quality; better plant diversity, vigor and production; and improved wildlife habitat.
As with all landfill operations, planning is everything. The choice of grazing animal (i.e., sheep, goats, cattle, or horses) and the number of animals necessary is site-specific. To determine the best choices, SCS Engineers looks at site characteristics such as the age of the plants and the proportion of grass species present, the local climate, and wildlife species present.
A landfill operator in California using sheep to groom landfill slopes is pleased with the results after three months and plans to continue the grazing method in the upcoming years. “We use 400 sheep per acre, per day, and have 600 on-site.”
“We talked about it for years before we implemented this method,” he says. “We needed time to research the feasibility and the costs, but that isn’t a challenge for SCS; their environmental scientists have landfill expertise in gauging air, soil, water, inorganic and organic content. These are all conditions requiring careful consideration before bringing in sheep to graze.”
The operator was sold on grazing, seeing the environmental, economic, and safety benefits of this alternative to herbicides and staff maneuvering trimming equipment on steep slopes. Finding a shepherd was the next step. With all its benefits, the method does require human oversight.
Luis lives at the landfill in a trailer home, his base of operations. He grew up in Peru, herding sheep. The landfill operations staff trained him on landfill safety, and Luis, in turn, teaches landfill staff what to expect from the 600 sheep.
The herd grazes during daylight hours, clearing patches of mustard grass and weeds. “Sheep are a better choice than goats here; they are more selective and won’t eat native plants or damage the infrastructure by trying to eat it too,” says the landfill operator.
As the sheep graze on invasive grasses, they are preventing tumbleweeds and destroying the seeds while chewing. A further benefit is the fertilizer they leave behind supports the growth of native plants that require minimal grooming, are tolerant of dry conditions, and facilitate the protection of the landfill cover.
“Around here, where the climate is very dry, preventing tumbleweeds and flammable conditions is a priority. The herd is packing the groundcover down while they’re eating, providing a great alternative to mowing while helping control runoff,” says the operator.
The herd is low maintenance, thriving outdoors without shelter and needing only to have their water troughs filled. The shepherd has two helpers, a border collie for herding the sheep to new locations and another larger dog to help protect the sheep from coyotes. Both the dogs and the wildlife help cut down the number of burrowing animals, which for obvious reasons are not landfill-friendly.
Occasionally, the landfill operation staff helps Luis move the herd. He sets up new locations across the landfill as the sheep are grazing in another area. Then the dogs help move the herd to the new location. Keeping the sheep going in the right direction is hard work, explains SCS’s Regional Manager. “If one sheep breaks off, twenty more will follow. Depending on where we’re moving them, Luis may need extra hands.”
This natural “landscaping” alternative with all its landfill-specific benefits is working well. The sheep can do some damage, they sometimes rub along exposed pipelines scratching themselves, but the staff is quickly alerted to anything broken. Luis uses a lightweight grid fence to corral the animals. The battery-powered fencing helps protect the sheep at night from coyotes with a light “shocking” deterrent, similar to static electricity. It’s enough to keep the carnivores at bay along with the dogs’ help.
The SCS landfill operations team has adopted the two dogs. Their Field Services Regional Manager points out, “We didn’t plan on adopting them, but we just couldn’t help ourselves. These are hardworking animals, and Guardian, the dog protecting the sheep at night, can get Foxtail, a grass-like weed, caught in his fur. The seeds can injure dogs, so we inspect and brush them, and we watch to ensure they stay healthy. These dogs, like the sheep, are part of the team and important to helping maintain the landfill − not to mention they’re special to us.”
The sheep, dogs, and Luis are doing an exemplary job. The operator expects in two or three seasons to see a significant improvement in maintenance; each consecutive year, there is less undesirable vegetation. “It’s working well; next year, we will start grazing in January to help prevent more invasive new growth earlier in the season,” he says.
“Environmentally, I like to think we’re helping our client be a good neighbor,” he continues. “And we save the landfill 66 percent of their landscaping budget every year; that helps us all sleep better.”
The U.S. Environmental Protection Agency recommends ecological restoration and revegetation of landfills, abandoned dumps, mines, and other site containment systems designed to protect people and the environment from exposure and prevent contaminant migration. Grazing is one cost-effective and efficient option to consider supporting these priorities.
Find more landfill engineering and operations information.
Join SCS on June 10 for another client webinar. Using case studies, we show you how our clients tackle common challenges using proven GIS technology to reduce expenses and run more productively.
Property Development: Time is money on development projects. Environmental engineers use GIS to more accurately pinpoint potential contamination sources, conduct site assessments, strategize remediation solutions, and see sampling results weeks faster. Infographics and dashboards show if and exactly where to continue sampling without waiting weeks or months for reports.
Landfills: Operators make diagnostic and forensic use of GIS to address maintenance tasks faster. We’ll cover modeling 3D wells and liquid level data, showing how GIS embedded dashboards and infographics pinpoint exactly where to assign staff. At the same time, supervisors monitor completed assignments seeing real-time results and what still needs attention.
Siting Solid Waste Facilities: Decision-makers use multi-criteria decision analysis incorporated into a geographic information system to account for relevant technical data, environmental, social, and economic factors during the site selection of a waste transfer station. The resulting maps and infographics are useful at public meetings too.
May 27, 2021, from two separate U.S. Environmental Protection Agency (EPA) announcements:
EPA intends to reconsider and revise the 2020 CWA Section 401 Certification Rule
Congress provided authority to states and Tribes under CWA Section 401 to protect the quality of their waters from adverse impacts resulting from federally licensed or permitted projects. Under Section 401, a federal agency may not issue a license or permit to conduct any activity that may result in any discharge into navigable waters unless the affected state or Tribe certifies that the discharge is in compliance with the Clean Water Act and state law, or waives certification.
EPA intends to reconsider and revise the 2020 CWA Section 401 Certification Rule to restore the balance of state, Tribal, and federal authorities while retaining elements that support efficient and effective implementation of Section 401. While EPA engages with stakeholders and develops a revised rule, the 2020 rule will remain in place. The agency will continue listening to states and Tribes about their concerns with implementing the 2020 rule to evaluate potential administrative approaches to help address these near-term challenges.
The agency’s process of reconsidering and revising the 2020 CWA Section 401 Certification Rule will provide an opportunity for public and stakeholder input to inform the development of a proposed regulation, and will include sustained dialogue with state and Tribal co-regulator partners and local governments around these issues. EPA will begin a stakeholder engagement process in June to hear perspectives on this topic and how to move forward. More information will be available at: www.epa.gov/cwa-401.
EPA, Region 7, public listening sessions on the RMP Rule
Section 112(r) of the Clean Air Act Amendments requires EPA to publish regulations and guidance for chemical accident prevention at facilities that use certain hazardous substances. These regulations and guidance are in the Risk Management Plan (RMP) rule, which requires facilities using extremely hazardous substances to develop a Risk Management Plan that:
These plans provide information to local fire, police, and emergency response personnel to prepare for and respond to chemical emergencies in their community.
The Region 7 EPA announced two upcoming virtual public listening sessions on the Agency’s Risk Management Plan (RMP) rule. The RMP rule has been identified as an action for review under Executive Order 13990: Protecting Public Health and the Environment and Restoring Science To Tackle the Climate Crisis.
The listening sessions will give people the opportunity to present information, and provide comments or views pertaining to revisions made to the RMP rule since 2017. The Occupational Safety and Health Administration (OSHA) will also participate in the listening sessions and receive comments on their Process Safety Management (PSM) standard, which contains similar requirements to the RMP rule.
Virtual public listening sessions will be held on:
For more information on the public listening sessions:
https://www.epa.gov/rmp/forms/virtual-public-listening-sessions-risk-management-program-rule.
Submit written comments via the docket at: http://www.regulations.gov, Docket ID: EPA-HQ-OLEM-2021-0312 until July 15, 2021.
EPA Region 7 serves Iowa, Kansas, Missouri, Nebraska, and Nine Tribal Nations.
SCS Engineers periodically prepares SCS Technical Bulletins – short, clear summaries of U.S. Environmental Protection Agency (EPA) rules and plans. On May 21, 2021, the EPA published a Federal Plan to implement the new Emission Guideline (EG) rule for municipal solid waste (MSW) landfills. The Federal Plan is published under Title 40 of the Code of Federal Regulations (CFR) Part 62, Subpart OOO.
Read, share, download the Federal Plan for Landfill EG Rule Tech Bulletin here.
It goes without saying: landfill operators are forever working to stay on top of odors, especially when the community smells something and points to the landfill or when regulators come calling. This blog shares two odor stories: one around landfill gas and another around trash. Then it looks at what happened when an operator got a permit restriction over alleged hydrogen sulfide emissions; odor was not the problem here. It was a perceived health risk; learn how SCS proved a predictive model was off the mark.
Is Landfill Gas a Source of Community Odors? And Ensuring Compliance
Living up to landfill odor nuisance standards is tough. The underlying premise is that odors must limit peoples’ ability to enjoy life or property to create a public nuisance, but it’s a subjective call. How strong an odor is and sometimes even if it exists depends on perception, so the question becomes: when they aren’t sure what they are being measured against, how do operators comply and prove compliance?
SCS recently helped a client figure out how to accomplish this after receiving odor complaints from the community, ultimately leading to a state agency-issued violation.
“We needed to thoroughly investigate to identify and mitigate odors, then prove compliance to the state regulator. Making a strong, valid case without having a numeric standard to go by takes both creativity and a scientific approach,” says Pat Sullivan, SCS senior vice president.
Sullivan, a biologist and his team of meteorologists, air dispersion modelers, and engineers, had a good starting point. They knew landfill gas was the source of the problem. But they needed more data to get to the root of that problem, and the operator’s required surface monitoring did not tell enough of the story.
The team launched a series of studies relying on multiple investigative tools.
“When we may have to put in more gas collection components, as we did here, we want to be sure we install them exactly where they are needed. This entails going above and beyond the standard modeling with a more rigorous methodology to get a comprehensive landfill gas emissions footprint,” Sullivan says.
SCS began by bringing out a drone to reach more landfill areas than technicians on foot for better coverage. The drone can fly over slopes, areas too dangerous to walk due to constant movement of heavy equipment, and areas inaccessible because of snow and ice. As it flies, it shoots a laser, which identifies methane based on the light refraction by methane molecules—then incorporates the data into a map for a comprehensive, visual picture.
Knowing methane concentrations at specific locations is important, but determining where to be more vigilant in controlling landfill gas also requires knowing hydrogen sulfide (H2S) concentrations. Sometimes overall methane levels are within acceptable limits, but the hydrogen sulfide in it is elevated, which could be a problem, Sullivan explains.
Getting a good grasp on H2S’s potential impact is tricky, as levels can vary radically from one area of the landfill to another. Pat Sullivan, SCS senior vice president, has seen them range from 100 parts per million to as high as 100,000 at different locations.
SCS used a Jerome meter, a highly sensitive tool that precisely quantifies H2S down to low-level part per million levels. SCS took it across the landfill and then into the community in search of H2S hot spots.
At the same time that the team investigated surface emissions of H2S, they went deeper down, sampling each landfill gas extraction well for levels of this volatile sulfur compound to identify potentially problematic spots within the landfill gas system.
“For this, we used Dräger sampling tubes, a resourceful tool in that rather than sending 100 samples to the lab, we analyze them ourselves and get immediate results,” Sullivan says.
Technicians get accurate quantitative results within plus or minus about 20% and can view concentration readings out in the field. Results are recorded on field logs and entered into a database for future analysis.
SCS overlaid the methane data from the drone study with the H2S data on both surface emissions and wells to develop a roadmap to design a landfill gas system upgrade. It includes new wells and piping in focused areas and more blowers for increasing the vacuum to pull more gas.
“We saw immediate results,” Sullivan says.
“Total gas collected went up 15 to 20 percent. Complaints went down significantly, and our client has not received another violation since.”
Of course, as the landfill takes in more trash, it will generate more gas, so due diligence is ongoing.
“Problem-solving is a phased approach. You do what you determine to be most effective; evaluate; then do additional work to improve. We will continue to follow this site and fine-tune where needed to keep the system running efficiently and keep the community and regulators happy,” Sullivan says.
Taking Down Landfill Odors from Trash
New garbage on a landfill’s active face can be a source of offsite odors, but determining if the waste facility is responsible, and determining when, where, and how odors travel, takes forensic work. Landfill odor experts rely on multiple data sets and tools to understand what can be complex issues and ultimately devise the most effective odor mitigation program when necessary.
In a couple of recent scenarios in Southern California, SCS combined complaint data, meteorological data, and smoke studies to get a full picture that verified the decomposing waste was the odor source. Then staff helped nail down specific times the problem occurred and under what conditions; providing a concise window can save operators labor and other resources because they can execute proactive measures only when needed.
“We look at complaint data to learn the location, day, and time of the complaint, but these accounts are not reliable by themselves. So, we overlay this information with meteorological data to determine the wind conditions during those days and times. Weather-related data is important in vetting offsite odors because if the landfill is not upwind of the location when the complaints happen, there likely is another source,” says Pat Sullivan, SCS senior vice president.
Sullivan and his team begin their investigations in two possible ways – setting up meteorological stations at strategic areas on the landfill to capture wind-related data or capturing data from already situated stations. Then they produce wind roses from their findings, which graphically represent wind speed; how often the wind blows from certain directions; and how these two correlate. In these two scenarios, graphing wind data times during each day helped determine exactly when specific wind conditions are prevalent.
In one of the two cases, odors occurred in the summer and almost always in the morning. The data not only showed where the winds were coming from at those times, but also showed they were traveling at low to moderate speeds.
“We matched that information to complaints and confirmed that the wind conditions were indeed driving the odors,” Sullivan says, explaining the speeds were just enough to carry the odor molecules into the community but not high enough to disperse and dilute them.
“Now we have painted a picture of wind conditions that we can focus on to get more information. We are getting closer to designing a multi-tiered odor mitigation program,” he says.
The next step was a smoke study, which reveals how odors move offsite, identifying the exact pathways and movement trajectory. These details are important because to treat or disrupt odor molecules; operators need to intersect the odor plume before it leaves the site.
SCS odor experts release colored smoke at the time and location they believe odors are, based on the meteorological data. They film from a drone to get a bird’s eye view of the smoke plume as well as get a camera filming from a different angle, following the plume movement to identify its path out of the landfill. This method enables them to determine where to intersect the odors as they move through the air before leaving the site.
From this research came three recommended measures to take during unfavorable wind conditions:
One of the landfill operators now has the problem under control and has received no further violations.
The other site made many of the same changes and plans to open a second disposal area for smelly loads. This client has seen a significant reduction in complaints and violations, but it’s a work in progress. The next true test will come when Sullivan and his team reevaluate in the summer.
“We will see then if any improvements are needed and tweak the solution if needed.”
And as with our other clients, we are training operators on how to be proactive. We teach them how to identify and grade odors and how to follow set procedures. And we help them with strategy implementation,” he says.
Odor mitigation is an ongoing undertaking. The team continually assesses and quantifies emissions and potential impacts.
“We look for changes that will control odors or prevent them in the first place. And we provide clients with the know-how and support to stay ahead today and into the future. Landfills and waste volumes are growing and changing. It’s a dynamic scenario. And we continue to build on what we have proven and adjust to keep up to make more progress,” Sullivan says.
Showing That a Model Can Over Predict H2S Emissions
Hydrogen sulfide (H2S) can be problematic even at very low concentrations, so this volatile sulfur compound is on federal, state, and local regulators’ radar. Some jurisdictions require the evaluation of air toxic emissions to determine potential health impacts to nearby communities.
They are also calling for these evaluations during permitting or to decide when controls are needed. To make these impact determinations, regulators typically rely on standard H2S risk assessments leveraging air dispersion modeling that predicts concentrations at locations away from the source.
However, this methodology, which includes estimates of emissions and predicts offsite concentrations based on algorithms that mimic how air moves, is not always accurate. Inaccuracy proved to be the case at one SCS client’s site. The model overpredicted offsite measurements of H2S that the state and local agency classifies as toxic.
Ultimately, the client entered into an enforcement agreement with the state because the operator had a permit limit, based on results of the risk assessment that it could not meet.
“Respectfully, the agency came in maintaining that the levels were out of compliance; it came as a surprise and seemed questionable to our team given our experience. We felt that the air modeling and risk assessment results derived from this modeling were not accurate,” says Sullivan.
First, his team tried to adjust model inputs and variables that would yield what they believed would be more accurate data. Even though they could show improvements, the model adjustments could not obtain readings that showed compliance with the risk-based limits.
Next, they began going out monthly and measuring real concentrations at receptor locations. The team used a Jerome sensor, a highly sensitive handheld device that detects H2S down to single-digit parts per billion levels with good accuracy.
When they compared the predictions from the standard model to their readings on the same days of each month and same times of day, they confirmed the concentrations were well below the acceptable risk threshold.
“Because we did this over an extended period, we have continuous readings and a large data set from many locations that give a history and statistical validity,” Sullivan says. Every monitored value was substantially lower than the values predicted by the model.
“What that means is we could show that while there were onsite emissions, they were not escaping the landfill at levels that would exceed risk-based thresholds. That was useful in proving to the regulators that the landfill was actually in compliance with the standard, even when the model suggested it was not,” Sullivan says.
Now SCS is asking for revising its client’s permit and that the limitations are made more flexible based on real-time, longer-term findings. While the team is still waiting on the final permit decision, they’re confident they have proof that the site complies with the risk-based limit.
The outcome of this project has potential beyond possibly changing one permit for one operator, Sullivan surmises.
“We think the data developed from this study showing how the models can overestimate real-world conditions can ideally help other operators build a sound case in circumstances where they truly are in compliance.”
Related Resources
Staying Ahead of Odor Management at Solid Waste Facilities – This video recording is from a live session about the challenges of odors, including measuring them and the science behind them. Throughout the recording, the speakers’ field questions as they make recommendations for assessing and avoiding odors, regulatory issues, litigation, and responding to complaints.
The presentation and Q&A run for 1 hour 41 min. It’s well worth your time, with plenty of questions posed by solid waste facility operators, landfill managers, and composting operators answered.
SCS Engineers encourages you to share this video or any from our Learning Center. You can embed them at events and use them for in-house training. Look for our
SCS Engineers is expanding its environmental expertise with Nathan Williams, PE, as an Environmental Engineer in the firm’s Portland, Oregon office. Williams will support SCS’s growing client base in the region to meet and remain compliant with local, state, and federal regulations that impact their business or municipality, with particular emphasis on stormwater compliance and management.
Washington, Oregon, and Idaho clients have regulatory requirements that include Compliance Audits, Spill Prevention and Countermeasure Plans (SPCC), Stormwater Pollution Control Plans (SWPCP), Air Pollution Control Discharge Permits, Risk Management Plans, Form R reports and Resource Conservation and Recovery Act (RCRA) Part B. These plans and permits address regulatory requirements and help protect watersheds and wetlands that provide drinking water to downstream communities, habitat for fish and wildlife, and countless other public and economic benefits.
Williams brings expertise and credentials to provide comprehensive stormwater management services to support businesses in the region ranging from vineyards to landfills. His experience includes working on permitting and remediating contaminated sites for industrial, residential, and power generation reuse across Oregon and Washington.
As a Certified Erosion and Sediment Control Lead, Williams has extensive experience in erosion and sediment control projects, from design, permitting, implementation, and project closeout with final stabilization. Combining these skillsets helps businesses continue to deliver products and services on schedule as they encounter increasingly rigid compliance regulations.
As with all SCS Engineers employee-owners, Nathan Williams engages in industry associations and his community. Learn about Nathan and how his work on the SCS team helps municipalities, all citizens, and businesses thrive.
About SCS Engineers
SCS Engineers’ environmental solutions and technology directly result from our experience and dedication to industries responsible for safeguarding the environment as they deliver services and products. For information about SCS, watch a short video, visit our website, or follow us on your favorite social media.
