Excess Biogas (environment issue)

[Aodwan]

Dear All,

Need your suggestion for this, we have new biogas plant to treat spent wash.
But before that we send lot of untreated waste water to cover lagoon, where there is no
Treatment takes place. Just stored waste water from last five years.

Since this is covered lagoon, there is excess biogas generates and currently we do not have
any input and output for this pond except the input coming from plant just to store waste water.

Now we have environment issue as the biogas ballon is very high and tight.

I need suggestion how to reduce/ decrease biogas level? I understand this is our mistake
That we ignore and not treated that. Sorry for long story.

Please advise.

 

[JedClampett]

Flare it?

 

[zelgar]

For the existing gas, you'll need to vent/flare/collect it in a safe manner. In the future, if you do not want biogas to accumulate in the lagoon, you'll need to aerate it to keep to oxygen levels high enough to prevent anaerobic conditions.

 

[dhengr]

Aodwan:
Instead of just flaring the gas, why not use it for some process or building heat? This may not be a continuous heat source, but why waste it or just adding the heat to the environment by flaring.

 

[Aodwan]

Thanks for your suggestions.

Since there is no piping( inlet / outlet ) and we need to down the level of gas
quickly before it becomes local issue, can we add some acid to lower the pH
through inlet pipie of spent wash coming from plant( only one inlet we have )

Is it work ? Since flaring and aeration needed more piping work.
Though we all understand this mistake not to treat this.

 

[BigInch]

Generate electricity with a biogas engine driven generator

https://powergen.gepower.com/applications/biogas.html

 

[bimr]

Flaring the gas is the most practical method to reduce it.

While generating power from waste gas appears to a great concept, in reality it is very difficult. One significant problem is that waste gas generally has impurities that tend to foul and destroy the gas generators. The other problem is that the gas stream will generally have a variable flow rate rate. The variable flow rate makes the process undependable if you want to use the waste stream for heating.

Have you considered changing the process to an aerobic process? That would end the problem of waste gas.

 

[JedClampett]

A client of ours tried selling the waste gas to the local gas utility. Another bad idea. The gas utility wasn't going to take any old nasty biogas. They wanted it perfectly clean. So a scrubber had to be installed. The scrubber took two maintenance guys full time to keep it running. And they sold the gas for maybe $100,000 a year.
So the scrubber is gone and they flare the gas.

 

[Aodwan]

Thanks to everyone. Now we have decided to aerate the system.
Dont know how much it will work, but that is the best way to reduce the waste gas.

 

[zelgar]

Aerating will only help by preventing additional gas generation. Before you aerate, you'll need to deal with the existing gas. I wouldn't be surprised if you're above the UEL (Upper Explosive Limit) of the methane gas currently trapped by the cover. The worst thing to happen is to add air into the system and get between the UEL and LEL and have an explosion.

 

[Aodwan]

Zelgar, we also thought the same, and still believe in
Conventional operation i.e. Flaring it. The results are positive
though will take some time . Thanks a lot for your suggestions.