The recent settlement between the Michigan Attorney General’s Office, EGLE, and the Arbor Hills Landfill included a requirement to install an air emission monitoring system on the eastern perimeter of the landfill (Perimeter Monitoring System). The system was designed to detect excess emissions and conditions which may result in noxious odors in downwind neighborhoods. The system has been touted as one of the most advanced landfill monitoring systems in the country and has been an effective tool to quickly detect and diagnose catastrophic equipment failures. (e.g. – noxious odors in March of this year were quickly determined to be due to a flare outage that was not detected. The noxious odors were corrected by fixing the problem with the flare).
During the first 23 days of June, residents downwind of the landfill submitted over 100 valid odor complaints. The odor complaints were mainly the neighborhoods located very near the landfill, Steeple Chase and Northville Ridge. The Perimeter Monitoring System data gave very little indication of excess emissions or noxious odors during this time period (see analysis below). Methane (CH4) concentrations never approached the action level of 40 parts per million (ppm) required in the Settlement Agreement.
Fig 1 - 105 Odor Complaints were received June 1 - June 23, 2022
The Perimeter Monitor System was of little value in detecting the issues which resulted in hundreds of residents registering a complaint. Although it is only speculation, these conditions may have been the result of weather conditions (i.e. - temperature inversions) which caused the landfill emissions to evade the monitoring system but settle in neighborhoods approximately a mile away from the landfill.
Data Analysis
The Conservancy Initiative has compared data from the Perimeter Monitoring System to odor complaint data. First, the average Methane (CH4) concentration at all 6 monitoring stations was determined using data from May 5 – June 23, 2022 (all available dates). Data taken from Midnight – 7 AM was excluded, as it is rare to receive odor complaints at this time of day and the CH4 concentrations tend to drift higher when the evening winds are very calm.
Next, the CH4 concentration was determined on two days with a significant number of odor complaints. On June 10th 24 odor complaints were received but the average CH4 concentration was only slightly higher than normal (3.9 ppm vs 2.4 ppm). One air monitoring station, MS-4, increased from 2.3 ppm to 5.2 ppm CH4.
Fig 2 - CH4 Concentrations measured at Perimeter Monitoring Stations
On June 22nd the community made 12 odor complaints, but the average CH4 concentration measured was virtually the same as the overall average (see fig 2).
The Consent Judgement does not require Arbor Hills to take action until the CH4 concentration exceeds 40 ppm. As this simple analysis shows, the community located directly downwind of the landfill may experience significant noxious odors long before the 40 ppm CH4 is reached.
The Conservancy Initiative believes the perimeter monitoring system may be an excellent tool for detecting equipment failures (flare outage, loss of vacuum on GCCS, etc.) which result in significant odor events, but odor complaints reported by the community are better tools for responding to daily issues which require action at the landfill.
Unusual Vibrations/Noise
Many of the same residents on the western side of Steeple Chase and Northville Ridge subdivisions also experienced unusual noise and or vibrations that seem to be coming from the landfill. On or around June 11 and June 22, approximately 10 residents on each occasion complained to The Conservancy Initiative that something was causing their homes to vibrate.
I am reporting not for odor but for vibration of our home and loud echoing similar to if a helicopter …
… there is a very low-frequency noise coming from the landfill that is causing vibrations on the second floor of my house…
Windows were vibrating.. very noticeable in the west-facing windows.
Reports were also made to Northville Township and multiple posts were made on social media sites.
The Conservancy Initiative has contacted EGLE and Arbor Hills management. Arbor Hills believes the noise/vibration may be related to the operation of one of the flares, but they have not witnessed an occurrence as it has happened during off-hours. Arbor Hills has consulted with the flare manufacturers who have suggested preventative maintenance tasks which should reduce the possibility of noise issues. The landfill management seems to be willing to address this issue but they need it to re-occur so the cause can be diagnosed.
It is unclear if the recent odor issues and the vibration issues may be related. As always, please continue to report all the landfill-related issues to allow them to be addressed.