Typical Conditions
The organic matter that is placed in landfills goes through a decomposition process that is exothermic and releases heat inside the landfill space. There are also other exothermic processes such as metal corrosion, hydration, carbonation, and acid-base neutralization that contribute to the heat generation phenomenon in landfills. Municipal solid waste has a relatively low heat conductivity characteristic, which means the heat is not as easily conducted through the waste keeping the landfill interior generally warmer than the areas near the landfill exterior.
Landfills expel the heat in different ways; propagating through the waste mass to the air, ground, leachate, and gas heat sinks. The heat escapes the landfill at its boundaries by convection to the air above the landfill surface and by conduction to the ground below the waste. Heat can also escape from landfills through liquids and gases removed from the landfill. For example, by conduction, via leachate that flows through the waste and is removed by leachate sumps and by convection, and via gases generated inside the landfill that are removed through the gas collection system.
Special Conditions
The large majority of landfills in the country show no signs of special conditions indicating too much heat. The characteristics noted in this blog have been observed in a few large, deep, wet landfills. Field investigations at landfills with high temperatures revealed that the highest temperatures are generally located at mid-point to the two-thirds depth of waste from the top surface. Temperatures as high as 250 °F have been recorded by specialized measuring devices.
Under certain conditions, elevated temperatures may occur inside a landfill, and the excess heat changes the character of chemical reactions taking place in the landfill, such as the decomposition process of the organic matter. Other documented changes that may take place in accumulated heat conditions are: leachate becoming stronger with higher BOD, lower pH, higher carboxylic acids and salts; concentrations of certain acids increasing; carbon dioxide and carbon monoxide generation increasing; the ratio of methane to carbon dioxide decreasing; hydrogen generation increasing; landfill odors changing to a significantly pungent character; landfill settlement rates increasing; gas generation and gas pressure increasing; leachate generation increasing; along with other changes.
Research
Heat generation in landfills is studied by researchers, reported in technical literature and scientific papers by academia and the industry. A summary of the findings related to the amount of heat generated from municipal solid waste in landfills is presented in Table 1 of Heat Generation in Municipal Solid Waste Landfills posted on the California Polytechnic State University, Robert E. Kennedy Library website.
Since the issue of high temperatures in landfills is of extreme importance to landfill operators with respect to compliance, operations, and financial aspects of these cases, finding out the cause and sources of excess heat is a hot subject in the field of landfill science. The largest research grant supporting the on-going research in this field was awarded by the Environmental Research & Education Foundation (EREF) in December 2014. So far, three parts of a technical article explaining chemical mechanisms through which organic matter decomposes and generate various types of other chemicals and heat have been published by the researchers of the above grant in Waste360. The research is on-going, and more information will be published in future. Links to the first three parts of the above article are provided here:
Prevention, Diagnosing and Managing ETLFs
SCS was involved in the preparation of standards for large, deep and wet landfills for a major waste operator in 2016. The intent of the standards is to implement measures to prevent elevated temperature conditions in large, deep, and wet landfills. SCS’s experience at such landfills and its in-depth knowledge can be valuable to those waste operators who are either experiencing elevated temperature conditions in their landfills or want to prevent conditions forming in their landfills proactively.
About the Author: Dr. Ali Khatami
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Discovering unexpected pockets of soft soils at the time of construction can delay your project and drive up costs for landfills, support features, and many other types of construction. If you don’t find them, building over them can result in unexpected settlement affecting a structure or building, or cause a slope stability problem for a berm or stockpile. You can avoid both of these scenarios with early investigation and appropriate construction planning.
While landfill development investigations typically require numerous soil borings within the proposed waste limits of the landfill, it’s common to overlook perimeter areas. Pockets of soft soil deposits can be associated with nearby existing wetlands, lakes, or rivers; with wind-blown silt or ancient lake deposits from periods of glaciation; or with fill placed during previous site uses.
The landfill perimeter areas may contain tanks for leachate or fuel, buildings, perimeter berms for screening or landscaping, stockpiles, and other features. A tank or building constructed over soft soils could experience unexpected settlement affecting the performance and value of the structure. The potential for a slope stability problem can increase for a large berm or stockpile built on soft soils.
The first step to avoid these problems and identify problem soils is to include perimeter areas in your subsurface investigation. Perform soil borings or test pit excavations at the locations of the proposed perimeter features such as tanks or berms. If you encounter soft soils, address them like this:
Contact SCS’s geotechnical engineers for more information on how to find and test soft soil areas early in a landfill’s project schedule, so you can effectively address associated construction issues in a way that considers cost and minimizes unexpected project delays.
Pat Sullivan discusses two case studies that provide examples of two different approaches to odor management. The proactive approach resulted in a more positive outcome than the reactive approach. Although the odor issues never go away completely, the proactive facility has avoided lawsuits and regulatory enforcement and continues to have a positive working relationship with the community.
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Click to read Part I of this two part series. We’ll let you know when Part II is published soon.
Tuesday, October 10, 1:00 pm – 2:30 pm ET
This Air & Waste Management Association webinar covers the effective, sustainable operation of municipal solid waste (MSW) landfills in today’s changing environment.
The latest updates to EPA regulations in over two decades limiting air emissions from landfills will be reviewed in detail.
Participants will learn the available models for quantifying landfill gas generation emissions and which model to use in different situations as well as energy recovery from landfill gas, its emissions, and how control requirements can affect feasibility.
Oil and gas processing facilities, federal and local governments, landfills, land developers, contractors, industries with industrial hygiene plans can spend too much money for too little information if they don’t have an understanding of the limits and capabilities of their equipment and methods before the development of their Air Monitoring Plan (AMP) . That’s before considering the risk to their employees and to public health.
Even if you can’t afford a dedicated air monitoring group, you can eliminate the health risks, overwriting a plan, or overburdening your budget. A cost-benefit analysis and integrating stakeholders’ goals can help provide the guidance you need to develop a balanced air monitoring plan.
Start with this list of considerations when developing an Air Monitoring Plan (AMP). The list is followed by tips and suggestions which are helpful under specific circumstances.
Location of the monitoring site is initially dependent on the monitoring objective. For example, once it is known that there is a requirement to monitor for peak ambient H2S at a microscale site, it reduces the monitoring site location to specific areas. Hence, the first task when evaluating a possible site location is to determine the scale for which a candidate location can qualify by considering the following:
1. Location and emissions strengths of nearby sources, especially major source;
2. Prevailing wind direction in the area;
3. Nearby uniformity of land use;
4. Nearby population density.
To select locations according to these criteria, it is necessary to have detailed information on the location of emission sources, the geographical variability of ambient pollutant concentrations, meteorological conditions, and population density. Therefore, selection of the number, locations, and types of sampling stations is a complex process. The variability of sources and their intensities of emissions, terrains, meteorological conditions and demographic features require that each network is developed individually. Thus, selection of the network will be based on the best available evidence and on the experience of the decision team.
Developing an Air Monitoring Plan (AMP) can be a daunting task. There are many decisions to make that have downwind ramifications relative to budget, logistical constraints, and labor requirements. In addition, there may be competing goals in regards to the project stakeholders. SCS has the experience developing and implementing air monitoring plans and systems to meet these challenges; including developing site specific and network-wide AMPs for various monitoring objectives. SCS also understands the costs and demands of the implementation of AMPs on industry and government.
If you need to perform Air Monitoring or are in the initial steps of developing an AMP please contact for expert advice and guidance specific to your region and industry. We have robust programs and experts nationwide. We can also incorporate the use of remote monitoring controls and monitoring by our FCC authorized drones.
Author: Paul Schafer, SCS’ National Expert Ambient Air Monitoring
Thanks to you, our clients, SCS Engineers has received many awards and industry recognitions for research achievements and technology innovations. Engineering News-Record (ENR) recently released the Top 500 Design List, ranking SCS Engineers in the top 100 for the 9th year in a row. In the same publication, SCS is ranked in the Top 10 Sewerage/ Wastewater Firms.
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Historic fill is common on properties that were once rural and have become prime redevelopment sites as communities expanded. The fill may include contaminated materials like foundry sand, ash, demo and construction debris, and even municipal waste. In the past, these materials were used to fill wetlands or change the grade of the property before initial development. Today regulations have evolved, and state agencies require property owners to manage these materials appropriately during redevelopment. Also, particular types of historic fill are often not robust enough to structurally support your new building.
There are many different kinds of fill materials – each with different physical properties and different potential contaminants. Knowing what is on your property before you start designing the site layout, and certainly, before you start digging, will help you plan your project to save time and money, and to receive state agency approval.
Before You Buy
The more you know about the property and the earlier you know it, the better prepared you will be to make decisions about how best to protect yourself from potential environmental liabilities and prepare for the environmental and geotechnical issues that historic fill can cause. Since every property is unique, the first thing you need to do is gain a thorough understanding of the property’s history and past use. Invest in a comprehensive Phase 1 Environmental Site Assessment (ESA). Consider it a starting point for clues about the possible types and amounts of historic fill which may be present on the property.
If the results of the Phase 1 ESA warrant it, conduct a Phase 2 ESA and geotechnical study to collect soil, fill, groundwater, and soil vapor samples. The Phase 2 ESA and geotechnical studies will help you understand if fill and contaminants are present and the best options for addressing them during the development planning stage.
Historic fill on a property is no longer the impediment to development that it once was. Take these steps to get ahead of potentially contaminated historic fill, and keep your project on time and budget.
By testing early, performing a proper geotechnical evaluation, and incorporating design adaptations where needed, you can successfully develop projects with historic fill within your schedule and without breaking your budget.
SCS professionals are available to answer questions or concerns you may have pertaining to commercial, residential, or private development on brownfields – we provide remediation, brownfields, and Environmental Due Diligence services nationwide. Contact or one of our experts.
About the author: Ray Tierney
Ray Tierney, PG, is a Vice President of SCS Engineers and one of our National Experts on Sustainability. He has 30 years of experience in environmental and sustainability engineering and has helped a wide range of organizations control and reduce their legacy environmental impacts and liabilities, lower their costs, obtain grants and permits to expand, and implement cost-saving practices. Ray serves the Midwest region and projects throughout the U.S.
JohnTabella, PG, LEED AP®, is SCS Engineers National Expert for Environmental Due Diligence and for Federal Services. In this capacity, he oversees all aspects of environmental services opportunities and projects primarily throughout the eastern seaboard and supports on opportunities and projects throughout the U.S.
Floyd Cotter specializes in solid waste management projects. His project work involves all areas of solid waste management including planning, permitting, transportation, landfill design, construction, and monitoring. Floyd is also experienced in general civil engineering, construction oversight, environmental site assessments, closure and post-closure plans, and permit and contract document preparation. Floyd is located in the Central region.
Randy Bauer has nearly 3 decades of experience conducting environmental site assessments, subsurface investigations, groundwater monitoring programs, soil and groundwater remediation, and geotechnical investigations at industrial hazardous waste and solid waste facilities. Randy is available to answer questions on the western seaboard.
Increased separation and segregation correlate to additional space needs in transfer stations. Given the move to automation in solid waste collections, it is reasonable to assume that the processing of MSW is going to move toward automation as well.
In his most recent article, Mike Kalish discusses some of the key considerations for the development, or redevelopment of transfer stations today.
Mike Kalish, P.E., LEED AP, is a Vice President of SCS Engineers and SCS’s National Expert on Transfer Stations. He has been the Project Manager for major transfer station renovations and expansions in several states.
Imagine that one of your employees comes and tells you that a 100-gallon spill just took place at your facility and it is flowing swiftly toward a storm sewer on your property.
Suddenly all eyes are on you. What you do next will show your leadership and skill at addressing the issue and limiting the company’s liability. Are you ready to be the hero, or is spill preparedness the one item that just keeps slipping down your to-do list?
Use the techniques recommended in Chris Jimieson’s latest article to make your spill response training engaging and interactive for staff handling oil. Spill preparedness becomes part of your routine and you’re ready to be the hero if a spill occurs.
Improve Your Spill Preparedness
SCS Management Services™ helps many of our clients’ incorporate economic planning, financial analysis, and feasibility studies into their master planning and have requested copies of our articles. All can be found and filtered by topic area, and we are always ready to help you find the information you need.
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Contact Vita Quinn for more information. Ms. Quinn is SCS Engineers’ National Expert on Solid Waste Finance and Rate Studies. She has 12 years of experience as a financial analyst and management consultant. She has extensive experience working for local government and has developed financial sustainability solutions for various general governments, special revenue funds, and utility enterprise funds. Ms. Quinn has an MBA in Finance and a Bachelor’s Degree in International Economics.
An Exercise in Sound Fiscal Planning: A Rural County’s Public Works Professionals Evaluate Future Solid Waste Service Scenarios, Costs, and Financing Options
Residential Automated Collection Makes Sense for Idaho Falls
The Nuts and Bolts of Implementing a Residential Automated Collection Program
Conducting a Rate Analysis as Part of a Master Plan Study in Killeen, Texas
https://www.scsengineers.com/scs-articles/conducting-a-rate-analysis-as-part-of-a-master-plan-study/
Financial Tools Assist in Completing Cost of Service Studies
Conducting Solid Waste Rate Studies and Business Plans
https://www.scsengineers.com/conducting-solid-waste-rate-studies-and-business-plans/
Get a Firm Handle on Solid Waste Costs to Optimize Performance
https://www.scsengineers.com/get-a-firm-handle-on-solid-waste-costs-to-optimize-performance/
Cash Flow Analysis Forestalls Long-Term Debt
Is Privatization the Answer? You Need to Consider Several Factors Before Making the Decision for Solid Waste Services
https://www.scsengineers.com/publications/articles/page/11/
Developing a Strategic Business Plan for Your Agency
Economic Feasibility 101 – Understanding the Tools of the Trade
Assessing a Solid Waste Agency’s Financial Health
Are Your Rates Correct? Collection and Disposal Rate Studies are a Valuable Tool
Integrating Financial Analysis into Solid Waste Operations Planning
High Costs and Limited Markets Put a Crack in Glass Recycling
Recycling Trends in the United States
https://www.scsengineers.com/scs-articles/6555/
Calculated Decisions: An Engineer’s Feasibility Report Can Help Communities and Financiers Assess the Risk of a Waste Conversion Project
Anaerobic Digester Economics
Give SCS a call or send an email to if you have questions. Find your local office here: https://www.scsengineers.com/locations/. Visit our Solid Waste Planning Services page for additional information, articles, whitepapers, and case studies.
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