Methane removal from drinking water


Methane

Methane or CH4 is a naturally occurring gas commonly found in drinking water. It is colorless, odorless and
tasteless. It is not believed to present health effects in drinking water and is not regulated by the EPA.
Methane is the principal component in natural gas so it’s not uncommon to find it in ground water near
underground gas deposits.

Easily removed from water
Of the many possible drinking water contaminates methane is relatively easy to remove. Its physical
composition and lighter than air quality provides for simple treatment systems with few or no moving parts.
The fact that it does separate from the water so easily presents the primary hazard of the compound;
explosion or asphyxiation.

Potential Hazards
Typically methane in the air has the potential to explode when the level is between 50,000 - 150,000 parts
per million (5-15% by volume). The danger of asphyxiation generally presents itself only when the methane
level becomes extremely high. For asphyxiation to take place the methane must displace the air within the
space leaving the occupants without oxygen to breath. Because methane is lighter than air this displacement
generally would start at the upper points in the building and work it's way down.

How much methane is too much?

Because it is not considered a health concern in drinking water the EPA has not set a maximum contaminate
level. The Department of Interior has recommended installing treatment when methane levels in water are
above 28 parts per million (or .0028% by volume)

Removal methods

Almost all treatment methods take advantage of the methane's tendency to separate from the water and rise.
Venting the wellhead and aeration within a holding tank or pressure vessel are common approaches.
Selecting a proper ventilation path is critical. It should be oriented to avoid gas build up within structures.







Steve Cade is the operations manager for UMGL a water management and consulting company.                 
He can be reached at
scade@umgl.net or (206) 462-3153 Ext 201.                                               
More information is on the company web site
www.umgl.net