Southeast Calgary landfill stench traced to leachate system
After a year of air monitoring, the city identified the Shepard Landfill's leachate system as a source of the rotten grass odour that has plagued southeast neighbourhoods for years.
The persistent rotten grass smell that has plagued southeast Calgary for years may finally have a solution: the city has identified the Shepard Landfill's leachate system as a primary source.
After a year of monitoring air conditions near the landfill, the city's waste and recycling services team discovered that the leachate system—a network of pipes that collects liquid trickling through the landfill to send for wastewater treatment—was releasing gases through access points created during construction. "The landfill essentially burps," explained Sharon Howland, leader of program management for the city's waste and recycling services.
Residents in New Brighton, McKenzie Towne, Copperfield, Douglasdale and Douglas Glen lodged over 100 complaints during air sampling, and odour complaints peaked in 2022. The city responded by installing a new air monitoring system with more than 100 sampling stations that measure air compounds and cross-reference them with weather data, wind direction, and resident feedback through 311.
Howland said the city has known for years that bad odours naturally came from the Shepard Complex, which includes the landfill, a composting facility, and biosolids lagoons. Nearby agriculture work and wetlands have also contributed. But the new data allowed officials to pinpoint the leachate access points as a problem.
In May, the city sealed off the access points where gas was escaping. John Lee, president of the New Brighton Community Association, said residents expected some odour when moving near the landfill but the smell had worsened in recent years. "Some days it'll smell like dead, wet grass. Some days it smells like a city dump. Some days it could be compost," he said.
Howland said August and September—historically the months with the most complaints due to heat and stagnant air—will show whether the sealing work succeeded. The city intends to expand its monitoring system to detect other odour sources in the area.
The outcome will test whether infrastructure tweaks can resolve a nuisance that's driven residents indoors on hot summer days.