More than two years after odor complaints about Bristol, Virginia’s landfill began, city residents are still dealing with the stench, the price to fix it has jumped to more than $60 million and the city is now being sued by Virginia’s attorney general.
But what is actually causing the stink – which often smells like rotten, sour garbage combined with a chemical odor?
The smell can be attributed to a combination of factors, including a reaction taking place within the buried waste, a likely failure of the subsurface sidewall liner system, elevated temperatures and settlement, according to a 36-page report released in April 2022 by a panel of experts.
The 11-member panel was convened by the Virginia Department of Environmental Quality and asked to study the landfill problems and offer solutions.
The landfill is in a former limestone rock quarry on 138 acres of land on Valley Drive. It started accepting waste in 1998 and is a little less than half full. Its permitted capacity was 7.8 million cubic yards and about 4 million of that is unfilled, according to the report. Its depth ranges from 325-350 feet.
Primarily, the odor is believed to be coming from the landfill/quarry sidewalls, which is why the panel said they believe the liner has been compromised. That failure means there is poor contact between the landfill liner and quarry sidewalls, which “hinders containment of high-temperature landfill gases.”
“Dating back to 2018, gas emissions were observed exiting the Landfill along the sidewalls between the quarry rock walls and the Landfill sidewall liner system. These point source emissions are referred to as ‘chimneys’ which are present at various locations along the Landfill perimeter, specifically the eastern and western walls,” and several were seen by the panel during a March 2022 visit to the site, according to the report.
The “chimneys” are where most of the odors are being released into the atmosphere, the panel found.
Odors are also likely coming from the landfill surface because there is “inadequate interim soil cover material,” the report states.
The panel was provided with odor complaints to DEQ, which began tracking them in late 2020. Most of the complaints were of a chemical smell, which one resident described as a “smoke.” That smell was apparent to panel members during their visit to the landfill, the report states.
The panel also found that there are signs – including unusual odors, low relative methane content in landfill gas and large and rapid settlements – of an Elevated Temperature Landfill (ETLFs), but it said there wasn’t enough data to diagnose the state of those conditions. Left alone, those conditions will likely continue to develop, the panel said.
ETLFs are known to be deep and very wet, with a thick waste mass. They are characterized by temperatures at more than 131 degrees Fahrenheit over a large area for a long time, the report states.
Also, waste beneath the landfill surface is saturated with leachate, which is known to contribute to ETLF conditions, including the generation of odors. Leachate is a liquid, mainly water, that “percolates through a landfill and has picked up dissolved, suspended, and/or microbial contaminants from the waste,” according to the Environmental Protection Agency.
There is also settlement at the landfill, which likely contributes to oxygen intrusion and inability of the gas extraction wells to efficiently collect gases and dissipate heat, the report states.
The panel’s 10 recommendations for odor mitigation were:
- Test and construct a sidewall odor mitigation system around the landfill perimeter.
- Improve performance of existing gas extraction wells and add wells to reduce emissions and temperatures.
- Identify and eliminate any landfill gas fugitive emissions at the surface and monitor weekly.
- Install settlement plates and conduct monthly surveys of settlement in the waste mass.
- Install and monitor a dedicated system of thermocouples in the waste mass to monitor temperatures.
- Install at least five deep dedicated monitoring wells to enable sampling and characterization of leachate and measurement of temperatures in the waste.
- Install and operate large-diameter, dual-phase extraction wells for removal of gas and leachate.
- Install a temporary geosynthetic cover over the entire landfill.
- Develop and implement an effective and sustainable stormwater management plan and settlement management plan.
- Conduct community outreach to communicate strategies, progress and get feedback.
Since the panel’s report last spring, the city has been completing the steps recommended with the assistance of a variety of experts, engineers and area contractors, according to information from City Manager Randy Eads that was posted on the city’s website Friday.
That work is in addition to prior efforts at the quarry landfill and is expected to result in “capping” the landfill, according to the city. The city stopped accepting waste at the landfill last September.
In acting on the recommendations, the city is also taking a variety of actions, including:
- Continuing to install a sidewall odor mitigation system, which began in December.
- Monitoring temperature, gas and water in and around the landfill.
- Installing additional gas wells to pull gas and liquid from the landfill.
- Implementing a stormwater monitoring system.
- Capping the landfill with a geomembrane that will further stop gases from escaping.
Capping a landfill is a process that involves a number of steps and can include the use of clay, sand and gravel, a geomembrane and soil, concrete or asphalt to begin transition the waste site to its next use. The city will use soil as the main ground cover and is evaluating its options for long-term solutions or uses, according to the information from the city.
The city manager said he estimates the costs for remediation and closing the landfill to be $60 million, but noted that the number is fluctuating, and a final number will be hard to give until the bidding process for all projects has been completed.
Last week, three Southwest Virginia lawmakers, Sen. Todd Pillion, Del. Israel O’Quinn, and Del. Will Wampler, all Republicans from Washington County, filed budget amendments asking the state to provide $12 million to help pay for remediation work at the city’s landfill.