In June of this year several residents in the area between Beck and Sheldon Roads, south of Seven Mile Road, complained of noxious odors. When the odors were traced to the sanitary sewers, work crews from both the Township and the Western Township Utility Authority (WTUA is responsible for the sanitary sewer system from Northville to the treatment plant in Ypsilanti) were called to investigate. Testing determined the sanitary sewage contained higher than allowable levels of hydrogen sulfide which was resulting in odors. Additional testing along the path of the sanitary sewer confirmed the source of the problem was the Arbor Hills Landfill operated by Advanced Disposal Serviced (ADS).
ADS has a contract with Northville Township and WTUA to discharge up to 110,000 gallons per day of industrial wastewater (leachate) into the sanitary sewer system. The contract is a 40-year contract and has been in place since 1992. The leachate must meet limits defined in the township ordinance before entering the sanitary sewer. The leachate is treated under a permit with the Ypsilanti Community Utility Authority (YCUA). For almost 30 years wastewater from Arbor Hills has run through the sewer system for treatment without significant issues.
Following an investigation, the Township expeditiously issued an Administrative Order for a Show Cause Hearing on June 22nd to ADS. The hearing took place on July 8th. A Show Cause Hearing is a required step in the process before the Township could break its contract with ADS and prohibit future discharges into the sanitary sewer.
Leachates at Arbor Hills are normally pre-treated before either being trucked or discharged into the sanitary sewer. The pre-treatment reduces hydrogen sulfide levels to minimize odors. It appears the problems in the sanitary sewer began when ADS modified its leachate collection processes which caused an imbalance in their pre-treatment process. Since being notified of the problem, ADS has made changes to their pre-treatment process and has been monitoring hydrogen sulfide levels in the sanitary sewer to verify their pre-treatment process is working effectively. Odors have not been reported in sewers since the changes over a month ago.
ADS has agreed to a Consent Order with corrective actions designed to prevent the reoccurrence of the sewer odors. The consent order includes:
ADS will install a hydrogen sulfide meter and datalogger in the sanitary sewer at a manhole located within the Township over a mile from the landfill. The meter will monitor hydrogen sulfide in sewer and record results every 30 minutes.
ADS will manually measure and record hydrogen sulfide levels at the monitoring manhole three times per day whenever the automatic meter is not operational.
The hydrogen sulfide level must remain below 10 ppm. The Consent Order defines actions to be taken in the event the limit is exceeded.
ADS will perform sewer cleaning and camera inspection of sanitary sewer from landfill to monitoring manhole twice per year.
Stipulated penalties of $500 to $1,000 per event per day are included for any requirements of the Consent Order that are not met (including high levels of hydrogen sulfide).
ADS will pay administrative assessment of $20,000 to the township.
Kudos to the team at the township who were able to resolve this issue quickly with a very narrow impact on the community. The Conservancy Initiative is hopeful that the fast actions taken to settle this issue are a sign that ADS may be getting ready to move forward and settle the larger issues which persist at the landfill.
Link to Update on Northville Township Website