Fires present a particularly dangerous challenge to landfill management. They can threaten the security of employees and harm the environment by releasing toxic emissions. Some fires can burn for several weeks or months, threatening a landfill’s profitability and resulting in devastating economic impacts.
In recent years, the occurrence of landfill fires has increased. In 2018, more than 8,000 fires were reported at waste facilities across the U.S. and Canada. The risk is especially high in the summer, where outside temperatures can rise significantly. The proliferation of lithium-ion batteries remains a common denominator in a significant portion of landfill fires. These batteries can spontaneously combust, acting as a spark in an environment that is dry and combustible.
Not all fires are created equal. Surface fires burn on the top layer of a landfill and can be started by lightning, hot waste, or arson, and are relatively simple to put out. Deep-seated fires, on the other hand, begin deep in the landfill. These are usually caused by buried heat sources or spontaneous combustion from decomposition or chemical oxidation. Detecting them is much more difficult, but common signs include subsurface temperatures exceeding 170 degrees, elevated carbon monoxide levels, combustion residue in wells, temperatures of extracted gas reaching above 140 degrees, and the smell of smoke in the gas extraction system.
Due to the varying types of materials found in landfills, there is no single best practice in extinguishing waste fires, as prevention is the goal. Should a fire start regardless, options include excavation, burying, water injection, nitrogen or carbon dioxide injecting, foam-based methods or freezing the ground. These methods are costly and, depending on the fire, might not be completely effective, requiring the combination of multiple options in order to work. Only by preventing a fire can one avoid devastating environmental and economic impacts.
To avoid deep-seated fires, compaction is an effective strategy. The denser the waste, the less oxygen and lower the risk of combustion. Smoke detector systems might seem like a good idea, but in an open area such as a landfill, where fires start by burning at low combustion levels in low-oxygen environments, waiting until smoke is visible can mean it is already too late. Smoke is also often confused for steam, which, though harmless, is often spotted in landfills. Prevention should also be part of every step in the process, starting with ensuring that nothing hazardous or combustible has been inadvertently buried. Asking questions about risky loads, such as how long ago it was picked up, whether the temperature was checked or if any risks were assessed will help in mitigating the amount of fires.
Failing all that, the best method to prevent large-scale fires is continuous monitoring and surveillance. Wastack’s Smart Thermal Camera can monitor landfills even when no one is around. The Smart Thermal Camera is always watching, twenty-four hours a day, seven days a week, so that even when everyone has gone home for the night, the thermal monitor keeps watch. If a fire is detected, the system will send a message to alert the owner of an ignition, and automatically call the local fire department to prevent the fire from escalating further. Contact a sales representative today to ensure you have the best tools available to prevent fires at your landfill, transfer station or Material Recycling Facilities.