Dear Linas jurgutis,

Hydrogen sulfide (H2S) is always present in biogas, normally at concentrations between 80 – 4,000 ppmv depending on the feed.Methane gas is derived through anaerobic digestion processes used by, among others, food processors, landfills, waste treatment, water treatment, and livestock farms. To produce biogas, methane gas first needs to be purified by removing the hydrogen sulfide (H2S). Once the H2S is efficiently and economically removed, the methane can then be reused for power generation, cogeneration, and heating applications.

A large number of technologies exist to remove H2S from gas streams

Following are Procedure.

1. A biogas plant in south Sweden is now treating it's H2S emissions with Ozone Tech Systems ozone generators. The complete system was delivered on a plug & play skid to simply installation and operations. The H2S ozone treatment reduces the smell of the plant to the surrounding areas.

H2S + O3 ---> SO2 + H2O

2. With Eco-Tec's H2S reduction system, Please see the link

http://www.pollutiononline.com/doc/h2s-bbgpur-ibiogas-purification-systemib-0001

3. Internal biological desulfurization by addition of air

One common method for desulfurizing biogas is biological oxidation by atmospheric oxygen. To this end, air is injected into the gas space of the fermenter above the surface of the liquid, or into the secondary fermenter. A quantity of generally 8 to 12% by volume fresh air is added to the generated biogas stream by means of a pump [7]. As a result of the atmospheric oxygen, hydrogen sulfide is oxidised into elemental sulfur by microorganisms that grow on the surfaces in the gas space. This sulfur accumulates on the surfaces and ultimately passes back into the substrate, where it is partly converted into hydrogen sulfide again [8], the remainder being discharged from the fermenter with the fermentation residue.

2 H2S + O2 = 2 S + 2 H2O

Please see the attached pdf file.

Yes, according to Delgado et al. (1999) temperature influences the H2S in the biogas:

H2S GENERATION IN A RECLAIMED URBAN

WASTEWATER PIPE. CASE STUDY: TENERIFE (SPAIN)

Wat. Res. Vol. 33, No. 2, pp. 539±547, 1999

yes , many of the researchers suggested that temperature change has direct effect on H2S concentration during Biogas Production.

As sulfide production is a biological process done by sulfate-reducing bacteria commonly known as SRB which consume mutual  substrates with methanogens; changing process parameters such as temperature, hydraulic retention time (HRT), , pH, and organic loading rate (OLR). Many researches shows that rather than temperature the most influential variable on the H2S concentration  was found to be the retention time.

Also the reduction in temperature would have adverse effect on methane production which is the main usable part of bio-gas .

I hope articles in attached link below will be helpful.

http://publications.drdo.gov.in/ojs/index.php/dsj/article/view/3798

http://onlinelibrary.wiley.com/doi/10.1002/clen.201000372/abstract

http://lup.lub.lu.se/record/3409140

Conference Paper Reduction of hydrogen sulfide (H2S) from poultry based bioga...

http://www.jocet.org/papers/236-E0014.pdf