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Public Comment · Arbor Hills

Make Arbor Hills Energy Verify Clean Fuel on Every Turbine Run

by Trisha Kunst · resident living less than one mile from the proposed expansion border · submitted September 6, 2026

This is the comment I submitted to the Michigan Department of Environment, Great Lakes, and Energy on the renewal of Arbor Hills Energy's Title V air permit, filed September 6, 2026 through the MiEnviro public comment portal.

To: Diane Kavanaugh Vetort, Air Quality Division, Michigan Department of Environment, Great Lakes, and Energy (Jackson District Office)

From: Trisha Kunst, Northville, Michigan

Re: Draft Renewable Operating Permit ROP0000656 v3.0 for Arbor Hills Energy, LLC (SRN N1504)

Submitted: September 6, 2026, via the MiEnviro public comment portal (comment period closed September 9, 2026)

Please accept these comments on the proposed renewal of Arbor Hills Energy's Renewable Operating Permit. I live less than a mile from the Arbor Hills complex and publish public records about the site as open data on GitHub.

The draft ROP would make no change to permitted emissions. My concern is that compliance with the sulfur dioxide limits now depends on sulfur-removal equipment operated by another company and addressed in that operator's plan. The renewed ROP should make Arbor Hills Energy responsible for demonstrating that every turbine run uses gas that meets the permit's sulfur limit.

Why stronger monitoring is warranted

When landfill gas is burned, sulfur compounds in the gas, principally hydrogen sulfide in the available test results, are oxidized to sulfur dioxide. Arbor Hills Energy had exceeded applicable sulfur dioxide limits. The 2021 federal consent decree required either an RNG facility or a sulfur-treatment system to reduce those emissions. Under the chosen compliance pathway, landfill gas is now treated before it is sent to the turbines.

The treatment has been effective when tested. During the August 26 to 28, 2025 compliance test, hydrogen sulfide in the treated turbine fuel ranged from 2.6 to 6.2 parts per million by volume (ppmv). Calculated sulfur dioxide emissions were 0.05 to 0.10 pounds per hour, below the applicable limits of 0.41 or 0.5 pounds per hour.

The question is whether the permit will reliably detect a loss of that performance. The draft ROP sets an hourly limit of no more than 20 ppmv total reduced sulfur, measured as hydrogen sulfide, in gas used by the turbines. Yet after initial testing, it ordinarily requires only a monthly field sample and semiannual laboratory analysis. If a monthly sample exceeds 20 ppmv, testing increases to weekly. That approach can identify an exceedance after it occurs, but it may not show whether the gas met the hourly limit during each backup or peaker run.

The operating record shows why this matters. During EGLE's August 2025 visit, the RNG plant was shut down while the turbines and two landfill flares were operating. An operator reported that incoming hydrogen sulfide was about 375 ppmv and had recently ranged from 300 to 450 ppmv. The operator also reported that sulfur-removal media were changed about every 90 days and that some breakthrough was observed after 60 days.

The sulfur-treatment plan for Emerald RNG (SRN P1488) describes two lead-lag treatment trains. It calls for media replacement before hydrogen sulfide at the lag-vessel outlet reaches 20 ppmv and anticipates that media will remain effective for about one year, depending on incoming sulfur concentration and gas flow. A roughly 90-day replacement cycle, together with reported breakthrough after about 60 days, shows that actual conditions are materially more demanding than that planning estimate.

The same EGLE report documented a leaking pipe carrying untreated landfill gas. A repair weld caused another crack, and the operator decided to replace the pipe. It also recorded two DTE requests that summer for peaker operation: the turbines could not start for the first request because of maintenance, while two turbines operated for the second.

These facts do not show that the turbines are currently violating their sulfur dioxide limits. They do show that turbine compliance depends on a treatment system facing variable, sulfur-rich gas and frequent media replacement, including during intermittent operating modes.

The cross-permit gap

Arbor Hills Landfill (N2688), Arbor Hills Energy (N1504), and Emerald RNG (P1488) are separately owned but are treated by EGLE as one stationary source. The sulfur-removal system's lead-lag configuration, outlet trigger, and media-change procedures appear in Emerald RNG's plan. Arbor Hills Energy's Malfunction Abatement Plan addresses its gas-conditioning equipment but does not address sulfur-media breakthrough or loss of compliant desulfurized fuel.

The location or ownership of the sulfur-removal equipment should not leave a gap in enforceable responsibility. California's 2025 Landfill Methane Regulation rulemaking provides a useful model: the proposed amendments explicitly assign applicable gas-control-system duties to third-party owners and operators. Here, at minimum, N1504 should be prohibited from operating a turbine unless Arbor Hills Energy has timely evidence that the fuel supplied to it meets the 20-ppmv limit.

Requested permit changes

I ask EGLE to revise the renewed ROP to:

  1. Require a compliance demonstration for every turbine operating period. Require hydrogen sulfide or total reduced sulfur measurement before startup and at intervals sufficient to demonstrate compliance throughout each backup or peaker run. Continuous monitoring would provide the clearest demonstration if technically feasible. The data should be retained and reported to EGLE.
  2. Tie turbine operation to verified treated-gas quality. Prohibit operation when timely monitoring does not demonstrate that turbine fuel is at or below 20 ppmv, regardless of which entity owns or operates the upstream sulfur-removal equipment.
  3. Address sulfur-treatment failure in the Malfunction Abatement Plan. Add loss of compliant desulfurized fuel, including media breakthrough, as a malfunction condition. Specify response steps, shutdown criteria, notification, and the records required before turbine operation resumes.
  4. Require notification for abnormal gas-routing conditions. Require prompt notice to EGLE when the turbines operate because the RNG plant or sulfur-treatment system is unavailable, and identify the enforceable backup control pathway when gas cannot be routed to the RNG plant or turbines.
  5. Address the documented piping failure. Identify the permit or permits that require appropriate inspection and preventive maintenance of untreated-landfill-gas piping at this integrated source, and require records of failures and corrective actions.
  6. Document resolution of the 2025 violation. The draft staff report says the site is expected to be in compliance when the ROP takes effect. Please confirm on the record how Violation Notice VN-017118, issued March 6, 2025, was resolved and explain how the renewed testing and monitoring conditions will prevent recurrence.

The August 2025 results show that sulfur treatment can keep turbine emissions well below the permit limits. The renewed ROP should make that performance durable and verifiable during every operating mode, rather than relying mainly on monthly sampling and requirements housed in another operator's plan.

Thank you for considering these comments and entering them into the record for this renewal and any subsequent EPA review.

Trisha Kunst
Northville, Michigan
arbor-hills@trishakunst.com

Every figure in this comment traces to a primary regulatory record. Principal sources:

This is advocacy, prepared by a resident. It reproduces a comment submitted to Michigan EGLE and entered into the public record. Every figure traces to a primary regulatory record or a named source. Read the evidence brief on the landfill's elevated-temperature record, the written comment to the county on siting requirements, or write the county commissioners yourself. The underlying data and EGLE filings are published at Arbor Hills Monitor.