Learn about SCS Engineers Air Emissions Services
All landfills regulated under the NESHAP air program must comply with updated federal regulations by September 2021, including new requirements for landfill gas beneficial use treatment systems and gas system design plans. Additionally, the EPA is finalizing a federal plan implementing new NSPS air rules for landfills modified or constructed before July 2014, and not yet covered under an approved state plan.
At the state level, as part of a continued focus on greenhouse gas (GHG) reduction, Maryland MDE is expected to publish new regulations this year addressing landfill methane control.
Jacob Shepherd, P.E., will cover what landfills need to do to comply with the updated federal regulations and will discuss anticipated new requirements under the MDE regulatory initiative as an example of the direction states are moving.
This discussion takes place at REVISION 2021, an online conference.
For additional information, see our recent blog: Regulatory Alert: MSW Landfills Federal Plan to Implement the Emission Guidelines (EG) and Compliance Times.
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
(40 CFR Part 60, Subpart OOO)
On May 21, 2021, EPA published the final MSW Landfills Federal Plan, which implements the 2016 Emission Guidelines (EG Subpart Cf) under 40 CFR Part 62 Subpart OOO. The Federal Plan becomes effective June 21, 2021, and impacts landfills that have not triggered NSPS Subpart XXX requirements and landfills located in states and Indian country without EPA-approved EG Cf rules.
Affected are MSW landfills that commenced construction on or before July 17, 2014, and have not been modified or reconstructed since July 17, 2014.
The Federal Plan requires existing landfills that reach an annual emissions threshold of 34 metric tons of nonmethane organic compounds (NMOC) or more to install a system to collect and control landfill gas (GCCS). It also implements various emission limits, compliance schedules, testing, monitoring, reporting and recordkeeping requirements for GCCSs established in the 2016 Emission Guidelines for MSW Landfills.
The Federal Plan also establishes a definition for “legacy controlled landfills.” These are landfills that have previously satisfied the requirement to submit an initial design capacity report, initial (or annual) NMOC emission rate reports, and collection and control system design plan under 40 CFR part 60, subpart WWW; 40 CFR part 62, subpart GGG; or a state/tribal plan implementing 40 CFR part 60, subpart Cc.
If you are subject to the Federal Plan and are not a “legacy controlled landfill,” you must submit a design capacity report by September 20, 2021. And if the design capacity report indicates a capacity equal to or greater than 2.5 million Mg and 2.5 million m3 of solid waste, you must also submit an initial NMOC emission rate report within 90 days after the effective date of the Federal Plan (September 20, 2021).
SCS is working to develop a Technical Bulletin for distribution to our mailing list and on social media. The Bulletin will consolidate the Final Rule into several pages highlighting significant dates and key impacts for you.
(40 CFR Part 60, Subpart OOO)
EPA is submitting a pre-publication copy of the final MSW Landfills Federal Plan to implement the Emission Guidelines (EG) and Compliance Times issued on May 10, 2021. The Final Plan becomes effective 30 days after publication in the Federal Register, impacting any remaining landfills without approved EG Cf rules.
EPA’s federal plan includes an inventory of designated facilities and an estimate of emissions from those designated facilities. The Agency estimates 1,590 landfills will potentially be covered in 42 states and the US territories of Puerto Rico and the Virgin Islands, and one tribal entity.
SCS Engineers is preparing a Technical Bulletin for distribution to our mailing list and on social media. The Bulletin will consolidate 133 pages into several pages highlighting significant dates and impacts for you.
Affected are MSW landfills that commenced construction on or before July 17, 2014, and have not been modified or reconstructed since July 17, 2014.
EPA is implementing emission guideline requirements for existing MSW landfills located in states and Indian country where state plans or tribal plans are not currently in effect because they were not submitted or approved.
The Final 2016 Emission Guidelines for MSW Landfills require existing landfills that reach a landfill gas emissions threshold of 34 metric tons of nonmethane organic compounds (NMOC) or more per year to install a system to collect and control landfill gas (GCCS).
It also implements the emission limits, compliance schedules, testing, monitoring, reporting and recordkeeping requirements established in the Emission Guidelines for MSW Landfills.
Unless the landfill is a legacy controlled landfill, owners or operators of MSW landfills subject to the MSW Landfills Federal Plan must submit a design capacity report within 90 days after the effective date of the Federal plan (40 CFR 62.16724(a)).
Should the design capacity report indicate a capacity equal to or greater than 2.5 million Mg and 2.5 million m3 of solid waste a landfill can accept; then, an annual NMOC emission rate report must also be submitted within 90 days after the effective date of the Federal plan, and then every 12 months until the landfill installs a GCCS (40 CFR 62.16724(c)).
You may find a copy here on EPA’s website.
Contact your SCS project manager or for assistance. Follow us on Twitter, LinkedIn, or Facebook to receive EPA alerts and SCS Technical Bulletins, along with other news.
SCS Engineers, a top-tier ENR environmental consulting and construction firm, welcomes Professional Engineer Mary Kennamer to its environmental services team in Raleigh, N.C. As a Senior Project Professional, Mary is responsible for designing and engineering solutions to help landfills, manufacturers, and businesses comply with federal and state environmental regulations.
As a chemical engineer, Mary’s background and degree are useful to help North Carolina landfill owners prepare to meet more stringent federal and local air regulations. She will advise on air compliance issues, air permitting, compliance reporting, and consulting for landfills and manufacturing.
“Mary’s previous consulting experience and work with the US EPA is a tremendous asset and value for our landfill and manufacturing clients,” states Kenton Yang, the Raleigh office’s project director. “We’re excited to add another bright star to the Raleigh office.”
In order to permit new or expanding plants and facilities, there are complex environmental policies to meet. As an environmental and chemical engineer, Mary researches, plans, and completes the technical work for air permitting and compliance, SPCC, and due diligence that keeps owners in compliance and projects moving forward.
About SCS Engineers
SCS Engineers’ environmental solutions and technology directly result from our experience and dedication to solid waste management and other industries responsible for safeguarding the environment. For more information about SCS, please visit our website at www.scsengineers.com/, contact , follow us on your preferred social media, or watch our 50th Anniversary video.
SCS Engineers – Raleigh specializes in permitting and meeting comprehensive clean air, water, and soil goals and provides a range of services such as PFAS treatment, solid waste master planning, landfill technology, risk management, groundwater monitoring, pre-closure and landfill closures, and Brownfields remediation.
When Doug Doerr got a call from a Colorado-based landfill operator with a hot gas probe at his site’s boundary, Doerr’s day kicked into high gear. Chasing down gas migration problems is nothing new in an SCS client manager’s life, but that reality makes the job no less complex. And in this scenario, he was dealing with a site that he occasionally got called to visit, so to understand the problem fast, he needed the site’s historical data and the current information to fully picture what was happening.
Doerr started with basic landfill gas information from the client: the monitoring probe’s location and a drawing of the gas collection system to determine where the probe was in relation to the gas system. But as you know, that is one small slice of a king-sized pie.
“All the LFG data that I would typically wade through to identify the problem can be overwhelming, but I had a recourse enabling me to get up to speed quickly. It didn’t take long to assess the problem,” he says. That recourse is a combination of quick teamwork from his peers nationwide and sophisticated technology developed by SCS practitioners for landfill owners and operators.
“I queried our in-house landfill gas technical group (engineers, geotechnical experts, and field personnel). And got over 25 responses within several hours with suggestions, one of which came from Ken Brynda in SCS Field Services, who leveraged DataServices to help me identify and narrow down the potential cause of the problem,” recalls Doerr.
DataServices, a module of the SCS eTools® digital platform, collects, stores, manages and analyzes large volumes of continuously accumulating landfill gas data for individual sites or multiple landfills. The module provides a quick method to view landfill gas scenarios.
The beauty of it is that it generates maps and charts to visualize every well and every probe. These system components are viewed in relation to one another and in relation to the perimeter, where the methane on that Colorado site flowed. Further, SCS Field Services’ landfill gas gurus, such as Ken Brynda, plug-in specific parameters that keep a close watch on any well or a group of wells.
“I logged into DataServices and pulled data from the five wells closest to the hot probe, which showed we had vacuum, flow, and gas quality, indicating the wells were pulling hard enough. I shared the results with our landfill gas technical group responders in a table and range map I’d created. And they started chiming in,” Brynda recalls.
As responders viewed initial results from their respective bases around the country, Brynda churned out more information in a few hours, running point charts to capture the balance gas, methane, flow, temperature, supply vacuum, and the vacuum applied to each well. He looked for trends that narrow down cause and point to solutions.
Eliminating the Possibilities – Rule Out Well System Malfunctions
“It can take days if we’d had to do it the old school way with spreadsheets laid out in a lot of rows. But we could identify the potential problem in a matter of hours, backed by a comprehensive evaluation for the landfill operator in eight hours,” Doerr says.
When Field Services staff work to solve a problem with a probe, they look for an outlier, something from a group of wells that’s not behaving like the other wells. In this case, Brynda determined that the wells near the hot probe were functioning properly. DataServices eliminated potential problems by slicing through and analyzing large chunks of data confirming the system was working efficiently.
Next, we observed that the wells are likely too far away to pull gas back from waste, adjacent to the probe in question, where there are no wells.
“DataServices helped rule out malfunctions, and that’s a big deal because if you can confirm the landfill system is working properly, you have narrowed your focus and can look toward other possibilities, ultimately leading to corrective options,” Doerr says. Brynda and Doerr suggested putting in temporary wells in that area to avoid odor migration and health and safety issues.
Doerr continues watching the situation and is prepared with a several-point action plan to mitigate exceedances and avoid falling out of compliance. “We continue watching the data to ensure the gas collection system continues to function well. Should there be issues again, we’re able to fully identify the gas migration pathways and anything in the system that looks out of the ordinary,” Doerr says.
If the client decides to add wells in time, data from the expanded infrastructure will be added to the app and monitored. “As the number of wells grows, DataServices grows with it, adding any, and as much, monitoring and collection data as the operator wants. DataServices will always be in the background to monitor, collect and analyze LFG data in real-time, whenever we need it,” he says. Being able to store, organize, dissect and analyze unlimited volumes of information from one location is powerful. And not just because it helps operators identify problems as they are happening, but because it and our teams can support them in looking for trends over time. Keeping an eye on the activities that keep the systems in balance is less costly.
For Doerr, who spends time in the field but longer hours with his clients, DataServices and the ability to interact quickly with experts like Brynda help SCS deliver more value to clients. “As much as I’d love to master DataServices, I need to focus all of my time on my clients’ business and goals; having support from Field Services and DataServices makes us all more efficient.”
Landfill Technologies and Comprehensive Expertise
SCS eTools® and SCS DataServices®, now with SCS MobileTools® for viewing data and charts anywhere; available to pull landfill data into DataServices for analyzing. You can customize and focus on exactly what you need fast. As Doug and Ken emphasize, it’s info that you likely already have, but may not be able to use quickly for troubleshooting.
SCS RMC®, remote monitoring and control of landfill equipment and systems.
Comprehensive Landfill Services
The 2020 Compost Awards recipients, nominated by peers were honored this year at COMPOST 2021, the USCC’s virtual conference. The 2020 Small-Scale Compost Manufacturer Award, given to facilities producing 10,000 tons or less, was awarded to Big Reuse, New York City Compost Project. Big Reuse operates two community composting facilities in NYC, one in Brooklyn and the other in Queens. Big Reuse redeveloped a garbage-strewn lot into an effective facility beneath the Queensboro Bridge on NYC Parks land. Big Reuse works with the New York City Department of Sanitation, community organizations, and NYC Parks to collect food scraps and leaves for composting. Big Reuse composts 2 million pounds annually.
Greg has 35 years of experience in all aspects of solid waste management, including composting and solid waste management plans. He is SCS’s national expert for organics management projects. SCS offers comprehensive services including the design, permit, construction, and operations of compost and anaerobic digestion systems and facilities for public and private clients. Greg’s expertise includes all of these services and regulatory support, economic analysis, and technology assessment.
Outside of work, Greg is the Compost Team Leader for a community garden in Bergen County, New Jersey. The garden produces about 1500 pounds of produce annually, which is 100% donated to soup kitchens in Newark and New York City. He also manages a backyard compost system for use in his own garden.
SCS Engineers now provides the Augusta Environmental Services Department with engineering, environmental and testing, and Construction Management & Quality Assurance Services at the Deans Bridge Road Landfill, in Blythe, Georgia. The facility operates under the State of Georgia Environmental Protection Division as a Subtitle D Landfill, accepting up to 1,500 tons per day of waste. Active and closed sections of the landfill comprise approximately 1,177 acres of property. Some additional acreage contains ancillary facilities such as office and maintenance buildings, customer drop off area, sediment ponds, roads, and leachate holding facilities. The Augusta Department of Environmental Services is responsible for the landfill facilities, solid waste management planning for Augusta, and all residential solid waste collections. Additionally, the Department is responsible for the Augusta Brownfield program and other environmental compliance issues.
Landfills are carefully engineered facilities closely regulated and monitored to ensure they have the protections necessary to prevent contamination of groundwater, air, and adjoining land. Best landfill management practices include collecting and treating leachate – the water that passes through a landfill. The methane gas naturally produced from decomposing landfill waste is collected and converted into various forms of energy – including compressed natural gas. This alternative fuel powers Augusta Solid Waste trucks or is a substitute for pipeline natural gas.
The Department consolidated all landfill services assigning them to SCS Engineers, a professional environmental consulting firm with over 50 years of experience in performing landfill site acceptability studies, landfill design services, landfill environmental compliance activities. The firm was already engaged in the Landfill’s Gas Collection and Control System (GCCS) expansion. The consolidation of services provides a more cost-effective approach for permitting, design, operations, monitoring, and maintenance. The comprehensive SCS team is a uniquely qualified and experienced full-service consulting and engineering team with demonstrated relevant field experience in Georgia. Leading the team is Sowmya Bulusu, a Georgia Professional Engineer, with over 12 years of landfill engineering performed in accordance with the Environmental Protection Division (EPD) of the Georgia Department of Natural Resources, the Georgia Solid waste management Act, and other applicable federal, state, and local rules and regulations. As the Project Director, Carlo Lebron is a registered Georgia Professional Engineer for 15 years bringing over 21 years of experience on over one hundred solid waste projects.
“The SCS team brought the five-year permit review submittal package in early, giving Georgia’s Environmental Protection Division plenty of time to deem it administratively complete,” stated Sowmya Bulusu. “Working with our field technicians, we quickly identified and brought at-risk gas wells into compliance, used our drones to provide an aerial survey of the entire landfill, saving Department funds.”
SCS Engineers’ environmental solutions directly result from our experience and dedication to solid waste management and other industries responsible for safeguarding the environment. Click for more information about comprehensive landfill services.
SCS Engineers is a leading environmental consulting and contracting firm with over 50 years of expertise in designing, permitting, constructing, and operating landfills. The firm is a pioneering force in developing landfill design technologies in use today by most landfill designers in the United States and internationally. Dr. Khatami describes several of the more prominent of these technologies below.
Landfills without Terraces
SCS is one of the first landfill designers to develop the concept of straight-up 3:1 slopes for landfills with no terraces. The modern version of tack-on swales (also known as tack-on berms) for control of surface water runoff came about along with this concept. This technology simplified waste filling operations for landfill operators and added significant additional airspace to landfill facilities. This concept’s financial benefits for SCS’s clients over the past three decades exceed one billion dollars.
Pipe Downchutes
SCS developed the single-barrel downchute and double-barrel downchute systems combined with the tack-on swales for landfill slopes during final cover installation. SCS has been designing and constructing these systems since the early 1990s, and none of the constructed systems have experienced failure. System performance for such a long time is a clear indication of the design’s suitability in combination with the tack-on swales. These concepts eliminate numerous problems that arise with open surface downchutes and other downchute systems combined with terraces on landfill slopes. The construction simplicity and rapid system installation make them the most useful systems for our clients.
Leachate Toe Drain System
SCS was the first landfill designer that developed the concept of a toe drain to collect and properly dispose of leachate seeps below the final cover geomembrane. SCS coined the term leachate toe drain system or LTDS for standardizing the design over 20 years ago. The LTDS is currently an essential component of all landfill designs that experience leachate seeps on exterior slopes, and landfill designers are catching up with the concept.
Rainwater Toe Drain System
SCS was a pioneering landfill designer in developing the proper means for collecting and removing water from the final cover drainage layer located above the final cover geomembrane. SCS coined the term rainwater toe drain system, or RTDS, to standardize the design over 20 years ago. The RTDS concept is currently an integrated component of all closure projects designed and constructed by SCS and many other landfill designers.
Sustainable Landfill Design Concepts
SCS revolutionized the landfill base grades design by developing the Landfill Green Design concept over two decades ago. Many regional landfill owners welcomed the concept and its numerous benefits, including savings in construction material and increasing airspace, to name a few. Introducing the second generation of the landfill green design within a few years, SCS addressed solid waste rules in several states. The improvements apply to very long disposal cells, minimum slope values for the leachate collection pipes, and minimum slope for a disposal cell’s base area. Coining the second generation design a Landfill Green-H Design, with “H” for hybrid, SCS reflects the combination of the landfill green design concept and the traditional herringbone concept. Readers of the SCS Advice from the Field blog can look forward to an upcoming blog on the term herringbone soon!
Over the past two decades, SCS has increased the airspace of many large regional landfills by modifying their solid waste permits incorporating the first and second generations of these concepts. The savings in construction material for these facilities exceeds $130,000,000, and the added financial benefit related to extra airspace is nearly $300,000,000. These SCS design concepts not only reduce construction costs and increase landfill airspace; they also have other sustainable benefits that landfill owners and operators value to help meet their sustainability goals.
The third generation of SCS’s Landfill Green Design is now available. Landfill Green+ Design provides its predecessors’ benefits with a higher degree of sustainability to our clients.
Tiered Vertical Gas Wells
SCS developed the concept and coined Tiered Vertical Gas Well, or TVGW, for the largest waste operator in the world as part of the developing standards for preventing elevated temperature conditions forming in deep and wet landfills. TVGWs collect landfill gas from the entire vertical column of waste from the bottom lining system to the final cover system. SCS developed additional concepts for horizontal blankets and fingers around the TVGWs to improve gas collection and rapid vertical movement of leachate through the vertical column of waste, allowing leachate to migrate vertically down to the leachate collection system rapidly. TVGWs have been a necessary component of new disposal cell construction at deep and wet landfills since their introduction to the industry.
Recently, SCS developed the second generation of TVGWs, known at SCS as TVGW+. TVGW+ simplifies the construction of intermediary pads and improves the connection of the pads to the vertical wells. Horizontal blanks and fingers can integrate easily into the TVGW+.
Gas Release System at Lining System
SCS developed the concept and coined the term Gas Release System (GRS) for the largest waste operator in the world as a part of the developing standards for preventing the formation of elevated temperature conditions in deep and wet landfills. The GRS releases high-pressure landfill gas near the bottom of the landfill. Excessive pressure can adversely impact leachate flow within the geocomposite drainage layer above the lining system geomembrane. Landfill owners and operators can apply the GRS concept to non-wet or shallow landfills as long as gas pressure near the bottom lining system is an issue.
Clog-Free Leachate Collection Pipe System
Over five years ago, SCS developed a design for leachate collection pipes without geotextile, which is a primary source of clogging in the vicinity of leachate collection pipes. SCS coined the term Clog-Free LCS Pipe or CFPIPE to standardize the design. Leachate from the geosynthetic drainage layer flows directly into the gravel around the LCS pipe and then into the pipe without passing through a geotextile. Since its introduction to the industry, SCS incorporates the CFPIPE into the design of landfills requested by clients looking for sustainable and clog-free systems.
Superior Ranking
The development of these technologies and many other SCS Firsts illustrates the value that the combination of our engineers, consultants, field staff, and scientists brings to each client. Our landfill designers work in combination with other highly sophisticated landfill related technologies developed by SCS, such as landfill gas systems, renewable energy systems, SCS RMC® remote monitoring and control, SCS eTools® for data management and decision making, and stellar operation and maintenance services.
As environmental industry pioneers, we never stop striving to be the most valuable landfill full-service provider. We highlight industry Firsts on our website just beneath the photo headlines.
Corporate Headquarters
3900 Kilroy Airport Way Suite 300
Long Beach, CA 90806
Telephone
1 (800) 767-4727
1 (562) 427-0805 | FAX
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