Although solid waste management is an essential service to the community, sometimes it produces an unpleasant side effect – smelly odors. Our transfer stations are cleared of waste every day, so odor complaints for those facilities are uncommon.

When our landfill in Melissa opened in 2004, there were very few residents near it. Now, as communities in the region are growing and expanding, housing developments have been built as close as one mile away. Our landfill is unique in that there is a composting facility onsite and a feedlot nearby, both of which produce odors similar to the landfill.

Our 156 collection wells capture landfill gas before it leaves the landfill which will help to further minimize odor. An additional 11 wells are under construction and will be operational by June 2018. During construction there will be infrequent times when a section of the well field will be off-line to allow for connecting the new wells to the gas collection system. This usually lasts less than four hours but could potentially result in orders from that area.

Here are some of our most frequently asked questions about landfill odors

  • What's That Smell?

    Landfill gas is formed when buried solid waste decomposes. This process creates gases, the most common of which are methane (CH4) and carbon dioxide (CO2), which typically combine to make up more than 95% of the landfill gas. While these two gases are odorless, the unpleasant aromas are caused by the small percentage of other gases. The most common odors from the landfill are caused by hydrogen sulfide (H2S) and volatile organic compounds (VOCs). Hydrogen sulfide is most commonly recognized as a strong “rotten egg” smell. The smell of volatile organics can vary, but typically have a somewhat sweetly pungent smell.

  • What Does the Landfill do to Help Control Odor?

    We operate 156 gas collection wells to capture landfill gas before it leaves the landfill and harvest the gas for energy production. Every day, employees spread and compact the solid waste in the active area of the landfill as it arrives. At the end of each day, it is then covered with a minimum 6 inch layer of clean soil. This cover helps to control the odor, prevent litter from blowing around, prevent fire and ward off scavenging animals. An odor patrol assesses the presence of odors from nine different locations in Melissa each day the landfill operates. Monthly, the landfill surface is walked and inspected for excessive release of landfill gas.

  • Why Does the Strength of the Odor Vary So Much from Day to Day?

    The generation and spread of landfill gas depends on a variety of atmospheric conditions:


    Because water speeds up the decomposition process, landfill gas odors can become stronger in the aftermath of heavy rain.

    Barometric Pressure

    On days when the barometric pressure is low or dropping, it is easier for landfill gas to migrate from the landfill.


    During warmer temperatures, hot air rises taking escaping gas higher up into the atmosphere, where it is not as noticeable. In colder temperatures, the escaping gas and odors are held closer to the ground in greater concentrations, thereby creating a stronger smell. Wind helps spread the escaping gas and lessen their concentration, but days with little wind mean that odors may be more noticeable.

    Moon Phases

    Certain moon phases also contribute to gas migration, similar to the influence the lunar pull has on tides. The pull of a New Moon or Full Moon can make it easier for landfill gas to migrate from the landfill. On a cold, damp, cloudy, windless day with low barometric pressure, the landfill gas and their associated odors will be hardest to control.

  • Does the Smell Pose Any Health Risks?

    Even when odors are strongest, the air’s circulation significantly reduces the concentration of the gas to levels far below any that could be harmful by the time the smell is noticeable. See additional information provided in the links below.

  • How Do I Report Landfill Odors?

    Contact Gary Higgs, NTMWD Landfill Manager at (972) 442-5405 or for odor complaints so they may be investigated. This phone number is always staffed.