In some instances, methane gas can be found in groundwater and wells. Where it is technically not considered a health hazard when ingested, methane does present its own dangers. For one, it is a highly flammable gas and can be explosive when mixed with air and can be lit with as little as a static charge. Additionally, it can cause asphyxiation as it will displace oxygen if released in an enclosed space. On top of all these dangers, it may also cause issues and interfere with the proper functioning of well pumps and water systems.
Most methane gas that is located in wells is a result of the decomposition of organic materials such as vegetation. It can also occur due to industrial activities in the area such as coal mining, well drilling, landfills sites or pipeline leaks.
Methane can enter at both above and below the water level. As it is lighter than air, if it enters above the water level, it will quickly rise to the top and accumulate beneath the well cap. If it enters the water below, it can stay dissolved, but how concentrated it is will depend on the pressure and temperature of the water. When water is pumped to the surface, this causes a rise in temperature and a drop in pressure, allowing the methane to be released from the water. Heating the water can also speed up the release of methane which is why gas issues tend to be worse at hot water faucets.
When there is methane located in a well, there are typically some tell-tale signs. At a faucet level, there may be sputtering or spitting present and there might also be gurgling noises from the well itself, however, these can also indicate the presence of other dissolved gases such as carbon dioxide. Sometimes you can see the gas bubbles in water samples, it may look clear with bubbles or may be milky, frothy or have a blue tint.
The best way to determine if there is methane in your well is to have it tested by an accredited water-testing laboratory. This involves professionals coming to take a sample and then taking it to test for the presence of gases. You can also test the levels of escaped gases from your well by installing gas detectors and meters to monitor the methane levels in your property.
Methane gas can be removed from wells in a number of ways, some of the most popular methods are as follows:
If there is a small amount of methane located in your well, venting may be a suitable option. This involves installing a vent tube to the well cap in order to promote the release of methane that has accumulated below the well cap and reduce the concentration of dissolved methane in the water. If your well cap is buried or covered, the casing will need to extend above the ground surface, and then be fitted with a cap and vent.
Wells that are located in basements pose a particular problem as if there is methane present it will be released straight into the building above. In these circumstances, a sealed cap will need to be fitted and the vent should be installed through the basement wall to the exterior of the property.
When venting alone is not enough, aeration devices may need to be installed. Also known as air stripping, this process is done with a device that may be something as simple as a spray aerator enclosed in a tank or a packed tower aerator that collects and releases the gas.
In some cases, water may need to be pre-treated prior to installing an aeration device as if there is high amounts of iron, manganese or other contaminants in the water it may cause the unit to clog. Additionally, it may be necessary to install disinfection equipment as some devices will allow for bacterial contamination to occur.
That’s our guide on how to remove methane gas from well water. For more information about bio methane solutions, learn about what gas flaring is next.
