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Tier 3 NMOC Testing Using Apis Technology

  • Mar 3
  • 3 min read

Apis Innovation, Waste Management (WM), and Weaver Consultants Group collaborated on a U.S. EPA Tier III (Method 2E) Non-Methane Organic Compound (NMOC) test to evaluate the need for a landfill gas collection and control system (GCCS) at a landfill in Colorado. The project combined traditional EPA testing methodology with Apis’ automated, cloud-connected monitoring technologies to improve data quality, operational efficiency, and testing consistency.


Site Background

Buffalo Ridge Landfill (BRLF) presents a unique operating profile, with approximately 85% contaminated soil and special waste and only 15% municipal solid waste (MSW). As required by the Colorado Department of Public Health and Environment (CDPHE), the site completed a Tier 2 NMOC test to determine site-specific NMOC concentrations.


Due to regulatory constraints, contaminated soils could not be excluded from the NMOC analysis. When paired with EPA default methane generation factors, the site calculated NMOC emissions above the 34 Mg/yr regulatory threshold, triggering a requirement to install and operate a GCCS.


However, given the site’s arid conditions and low MSW content, it was evident that default EPA assumptions significantly overestimated methane generation and NMOC emissions.


Regulatory Path Forward

Pursuant to 40 CFR §60.35f(a)(5), BRLF requested approval to use a site-specific methane generation potential (LO) to better reflect actual waste composition. The EPA required that a Tier 3 NMOC test (Method 2E) be performed in conjunction with LO testing before approving an alternative approach.


WM then partnered with Weaver Consultants Group and Apis Innovation to conduct a Tier 3 NMOC test from August through October 2023, incorporating Apis’ automated wellhead and pressure monitoring technologies.


Test Design & Technology Deployment

The Tier 3 test utilized a combination of Apis devices, including:


Each smartWell was installed on a 2-inch wellhead and surrounded by three headerMonitors and nine pressureMonitors positioned within the radius of influence. This configuration enabled precise evaluation of gas flow, pressure response, and well interaction across the landfill.


The smartWell and headerMonitor devices are solar-powered and continuously measure key gas parameters, transmitting data via cellular connectivity to the Apis Cloud dashboard. smartWells autonomously tune individual wells to maintain site-specific performance targets, while headerMonitors track flow, pressure, and gas composition at header pipes. PressureMonitors captured subsurface pressure response in surrounding areas of the landfill.


Figure 1: Example of Apis Device Setup on BRLF


Operational Advantages

Unlike traditional Tier 3 testing, which relies heavily on manual field readings and adjustments, Apis devices enabled:

  • Real-time, remote monitoring and control

  • Continuous data collection

  • Remote tuning at 10-minute intervals

  • Reduced need for on-site personnel


During the test period, the system achieved 99% uptime, including a three-week period in which sampling and tuning occurred every 10 minutes throughout the day. This approach produced a more consistent and higher-resolution dataset than is typically achievable with manual methods.


Data Insights & Environmental Factors

The automated system also enabled detailed evaluation of external variables, such as barometric pressure, and their impact on gas flow and quality, an especially important factor at arid landfill sites.


Operators were able to:

  • Tune individual wells and observe pressure and flow response in surrounding wells

  • Incrementally adjust vacuum levels to evaluate radius of influence (ROI)

  • Assess vertical and horizontal gas movement across the landfill


This level of insight improved understanding of well interaction and supported more informed system optimization.


Below is an example of some of the data for one of the 27 pressureProbes. This illustrates the variations in oxygen, nitrogen, and pressure in the well and the probes


Figure 2: Oxygen and Nitrogen Data


Figure 3: Gauge Pressure Data


LO and k Determination

Although the initial objective was to obtain a site-specific LO, EPA Method 2E also allows for calculation of LO′, a revised methane generation potential that accounts for non-decomposable waste material.


Waste samples from the site were analyzed at North Carolina State University to determine biochemical methane potential (BMP). Based on this analysis:

  • LO′ was determined to be 22.06 m³ CH₄/Mg, significantly lower than the EPA default of 170 m³ CH₄/Mg


Following completion of all phases of Method 2E testing (Leak Test, Static Testing, Short-Term Testing, and Long-Term Testing), iterative calculations produced a site-specific:

  • k value of 0.019 yr⁻¹


Project Outcome

Using site-specific LO′ and k values, the NMOC emission rate was recalculated and found to be below the 34 Mg/yr regulatory threshold. As a result, the site was not required to install or operate a GCCS under NSPS/EG regulations.


Key Takeaways

In addition to avoiding unnecessary GCCS installation, the project demonstrated:

  • How modern automated technologies can be effectively integrated with legacy EPA Test Method 2E

  • The operational benefits of remote monitoring and control

  • The sensitivity of gas behavior to barometric pressure in arid environments

  • The value of LO testing for landfills with atypical waste streams


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