Landfill is Water-Logged Resulting in Uncontrolled Gas Vents
Northville - October 24, 2019
The Michigan Department of Environment, Great Lakes and Energy (EGLE) issued two new Violations Notices to the Arbor Hills Landfill operators, Advanced Disposal Services (ADS) and Fortistar Methane. (Click Links for Violations Notices).
The violations are based on data in a quarterly report submitted by ADS. The quarterly report identified the liquid (leachate) levels found in the landfill's gas wells. The violations allege the landfill operators are not adequately removing leachate, resulting in the landfill’s gas collection system becoming restricted or blocked by the leachate. In layman’s terms, the landfill needs to be dewatered.
Each of the landfill’s approximately 400 gas wells has a perforated screen were the gas enters the well. Leachate (water) that is encountered in the landfill will block the well screen, preventing landfill gas from entering. Leachate can cause scale build-up and can permanently block a gas well. Leachate must be removed from the landfill to prevent restricting the gas wells. Many of the wells are equipped with leachate pumps and more were added after a violation earlier this year, but leachate levels continue to increase.
When leachate is not adequately removed from the landfill, the gas collection system becomes restricted. Landfill gas will eventually find an alternate pathway and create an uncontrolled vent to atmosphere. EGLE has noted numerous uncontrolled gas vents during landfill inspections. EGLE has also identified over 20 pinched or damaged gas well which need to be addressed.
The violation notice does not cite any specific data, but it does state that conditions are getting worse. In March 2019, EGLE issued a similar violation notice to ADS based on data from September of 2018. At that time 215 wells were checked for leachate levels. 151 of those wells had 50% of the well screen submerged (blocked) in leachate. Of those 151 wells, 75 wells were 75% blocked and 35 were fully saturated with liquid. In September 2016, the USEPA reported 70 wells had more than 50% of the perforated well screen submerged in leachate. Good engineering practices note that no more than 25% of the well screen should be covered in water.
The primary disposal method for leachate from Arbor Hills is via the sanitary sewer system. There is limited capacity in the sanitary sewer which results in ADS incurring considerable higher costs to truck leachate off-site for disposal. It is important to note that this appears to be a long term issue that will take significant time to correct. Correcting this issue will require a commitment from ADS to upgrade leachate wells/pumps/piping and to truck significantly more leachate to off-site disposal for the foreseeable future.
A response to the Violation Notices are due from ADS and Fortistar by November 12th. The Conservancy Initiative will obtain and post their responses.