SCS Engineers periodically prepares SCS Technical Bulletins – short, clear summaries of rules, plans, and standards. The Colorado Department of Public Health & Environment (CDPHE) Air Pollution Control Division adopted the Colorado Landfill Methane Rule – Regulation No. 31 in 2025, which sets methane emission reduction requirements for landfills in the state.
Colorado Regulation 31 requires more landfills to install gas collection systems, tighten monitoring and control requirements (such as phasing out open flares near communities), and mandates biofilters on closed sites to better align with the state’s net-zero goals.
As an environmental engineering, consulting, and contracting firm with a strong portfolio in landfill gas operations, monitoring, and collection and control systems (GCCS), SCS helps Colorado landfill owners and operators proactively budget, plan for, and implement compliance strategies for the new Colorado landfill methane rule (LMR).
The SCS Technical Bulletin for Colorado Regulation 31 addresses definitions and terminology, clarifies industry practice for the waste industry, and provides for updates and additions to thresholds, advanced monitoring, and remote monitoring for data collection, closed landfills, and flares.
SCS provides these additional resources and services for Colorado LMR compliance, as follows:
For more information, contact:
This SCS Engineers blog provides a summary guide on landfill gas collection and control systems (GCCS), focusing on design, construction, operation, and maintenance of landfill gas (LFG) infrastructure. It covers essential components such as LFG headers, condensate management, isolation valves, and quality assurance processes, emphasizing regulatory compliance, safety, and optimization of gas recovery. We provide links to the details below, and our professional staff are always ready to answer questions.
Landfill Gas Collection and Control System (GCCS) Overview
The GCCS is a critical component of landfills that accept organic matter, designed to control odors and landfill gas (LFG) emissions to protect human health and the environment. Over four decades, GCCS has evolved from passive venting to sophisticated piping systems with specialized components for handling gas, liquids, and condensate flow within the piping network.
Primary Vacuum Conveyance Line
LFG headers serve as primary vacuum conveyance lines from blower skids to LFG wells inside the landfill. Maintaining the integrity of these headers is vital to avoid system shutdowns that could disrupt gas-to-energy operations, cause financial losses, and lead to air quality and odor issues, especially in urban areas. The headers are activated from the first day of GCCS operation and expand as the landfill grows.
Conveying Condensate: Slope and Gravity
As LFG cools, water vapor condenses inside the piping system, creating condensate that must be effectively removed to prevent blockages and flow interruptions. The system’s design ensures gravity-driven condensate flow toward collection points by maintaining positive pipe slopes—any dips or improper slopes risk hydraulic blockages and reduced gas extraction efficiency.
Isolation Valves on LFG Header Inside Waste Boundary
Isolation valves are installed within the piping network to isolate segments for maintenance without shutting down the entire system. They also facilitate cost-effective expansion by allowing new sections to connect without impacting existing operations.
LFG Header Crossing an Anchor Trench
LFG headers sometimes cross the landfill lining system anchor trench at the perimeter. Positioning headers in contact with the anchor trench can complicate final cover construction, potentially causing weak points and gas leaks. A recommended minimum clearance of three feet between the anchor trench and the LFG header bottom allows proper welding of geomembranes and system integrity.
Condensate Sumps Inside Landfills
Condensate sumps are placed at low points in the piping network, often inside the landfill footprint, where the LFG header follows a serpentine path. These sumps are vulnerable to damage from landfill settlement and may require vertical extension during landfill closure, causing operational interruptions. Designers are advised to locate sump tops above future final cover elevations and provide access for maintenance until closure.
Condensate Force Main Inside Landfills
Condensate collected in sumps is pumped via electric or pneumatic pumps into force mains that discharge to leachate systems or storage tanks outside the landfill. Force mains buried deep in waste must be structurally designed to withstand waste loads and avoid contact with the lining system anchor trench to prevent costly geomembrane welding issues.
Pneumatic Pumps Inside the Landfill
Pneumatic pumps require compressed air lines extending from compressors outside the landfill to power condensate sump pumps and liquid-removal pumps in LFG wells. These air lines must be designed to withstand compressive waste loads and avoid interference with the lining system anchor trench to maintain final cover integrity.
Collapsing LFG Header Buried Deep in Waste
In older, large landfills, multiple layers of LFG headers may exist vertically buried in waste. These headers can collapse under waste surcharge loads, reducing vacuum effectiveness. To compensate, new headers at higher elevations are added, creating a layering effect without waste extraction.
LFG Header Above the Final Cover Geomembrane
Constructing LFG headers above the final cover geomembrane provides maintenance access without disturbing the cover. However, it requires careful design to avoid conflicts with surface water management structures such as downchute pipes. Depressing down chute pipes and geomembranes at crossing points ensures proper condensate flow and water drainage [19] [20].
Benefits of Placing the LFG Header Outside the Waste Boundary
Locating the LFG header and condensate sumps in the landfill perimeter berm during cell construction offers multiple benefits:
Construction Quality Assurance (CQA) Services
CQA ensures GCCS construction complies with design intent, allows field adjustments, and documents construction events. It involves site familiarization, pre-construction meetings covering project scope, safety, permits, and coordination among all stakeholders. Regular progress meetings monitor work status and address issues. CQA personnel verify well locations before drilling and oversee safe drilling operations with odor control and fall protection measures.
Landfill Gas Collection and Control System Operation, Maintenance, and Monitoring (OMM)
OMM programs optimize gas recovery and compliance by implementing durable, beyond-compliance practices. Safety plans tailored to site-specific hazards are critical, including evacuation procedures and hazard communication. Monitoring plans review historical data, permits, and manufacturer recommendations to develop clear procedures and schedules. Wellfield tuning stabilizes the vacuum and addresses maintenance issues such as air leaks, surging, and liquid blockages. Compliance management involves tracking exceedances, reporting, and maintaining regulatory relationships.
Wellfield Tuning and Maintenance Details
In conclusion, SCS Engineers emphasizes careful GCCS design that considers final cover construction, recommends placing LFG headers in perimeter berms for operational advantages, and details CQA and OMM best practices to ensure system integrity, safety, and optimized landfill gas recovery throughout the landfill life.
Take a deep dive into these landfill topics, plus using LFG as a renewable energy source, and greenhouse gas reporting.
Please read the SCS Engineers’ series of landfill articles and resources published and available on our website:
About the Co-Authors: Sr. Vice President Ali Khatami, Ph.D., PE, LEP, CGC; Sr. Vice President Srividhya Viswanathan, PE; and National OM&M Compliance Manager David Fisher. Contact our authors or a landfill, LFG, and GCCS expert near you.
On July 7, 2020, the City of Brownsville Commission approved a recommendation by the Engineering and Public Works Department to continue an existing multi-year partnership with SCS Engineers. SCS is an environmental consulting and contracting firm that will serve the City for an additional five years. The environmental contracts support the Landfill Gas Collection and Control System (GCCS) expansion and provide landfill engineering, compliance, monitoring and operations assistance.
Project Director, J. Roy Murray, an SCS vice president, and the team’s principal consulting engineer will continue to serve the City’s citizens and staff. Mr. Murray has decades of experience in civil and environmental permitting, design, and construction at municipal solid waste landfills (MSW), including 20 years serving the Brownsville Landfill. Mr. Murray states:
The City staff and Commission continues to entrust SCS Engineers to help the landfill staff with the safe, efficient, and compliant operation of the landfill. We are honored by their trust. The City of Brownsville MSW Landfill Operations team serves the City well. The facility is the primary solid waste disposal site for surrounding communities, carefully engineered and maintained regularly even during severe weather and now a pandemic. The forethought of the Landfill Division, their leadership, and innovative practices provide the citizens with stellar services while protecting the environment.
The initial installation of the City Landfill’s Gas Collection and Control System (GCCS) completed in 2011, was part of an Energy Efficiency and Conservation Block Grant the City received from the American Recovery and Reinvestment Act of 2009. SCS Engineers assisted with the application process, and as a result of the collaboration, the City received a $1.7 million grant to install a landfill gas collection system at the landfill. With GCCS operation, the City has reduced its greenhouse gas emissions. The landfill infrastructure and emission reductions were voluntary at the time, but the Texas Commission on Environmental Quality (TCEQ) Air Quality rules and regulations, and EPA’s New Source Performance Standards, now require them.
The Gas Collection and Control System consists of 16 landfill gas extraction wells and currently provides coverage of 32 acres of the City Landfill’s disposal footprint. The City plans to expand the GCCS during 2021, to support landfill’s growth and stricter air permit regulations. The expansion includes 38 additional wells covering 120 acres of the landfill footprint. The new wells will integrate with the collection system and integrate with liquids management, leachate control, and stormwater systems, among others.
About SCS Engineers
SCS Engineers’ environmental solutions and technology are a direct result of our experience and dedication to solid waste management and other industries responsible for safeguarding the environment. For more information about SCS, please follow us on your preferred social media channel, or watch our 50th Anniversary video.
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