Enviros Methane Stripping
The aim of this web site is to provide a resource for all those promoting, designing, and regulating for the provision for safe removal of methane from solution, in landfill leachates, methane which would otherwise pose a risk of explosion or fire, in the sewers to which they discharge.
”Controlling dissolved methane in leachates discharged into public sewers is vital to minimise the risk of generating explosive atmospheres.”
The process of removing dissolved methane, by blowing air through leachate in suitable tanks, is commonly referred to as “methane stripping”.
Contents:
Click on any of the following links to enter that section:
Introduction
Explosion Hazard
Safe Concentrations
Experimental Trials
Trial Results
Full Scale Plants
Red Moss Methane Stripping Plant, Manchester
Kendal Fell Methane Stripping Plant
Red Moss methane stripping plant. Typical operating results
Methane Stripping Methods
The method of methane stripping we have adopted is that of aeration into 4 tanks of leachate placed in series.
An alternative technique is to utilise a column and create a contra-airflow within a cascade in a tower.
Health & Safety
A contra-airflow methane stripping column based upon a cascade would present us with concerns that in the event of a failure of the air blower the air within the cascade column may become an explosion hazard in it’s own right. In other words if the pumping system was to continue to run after failure of the ventilation system the air space would become saturated with methane at a concentration above the Lower Explosive Limit (LEL).
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A full scale methane stripping plant
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This is a much larger airspace than the top (freeboard) of a tank, and therefore the stripping column design is likely to be less inherently safe than the tank based design described here.
Common Mistakes in Methane
Stripping Plant Design
We have seen, and replaced, UK methane stripping plants which have failed, on a number of occasions. Some reasons for failure have been:
- Inadequate air flow rate
- Inadequate mixing in single tank designs
- Excessive calcification.
The first two can be avoided by applying basic science as described on this web site.The third is achieved in our systems, by unique process design features incorporated into our designs.
The image on the right shows calcification in progress. A 2-3mm deposit is visible on the tank wall between the red arrows
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