As increase concentration of H2 decrease the production, we are curently working on the influence of the mixing. The type of mixing could increase the interface exchange and so it could  increase the production of H2. Thesis about this subject in progress.

To promote H2 production to further convert it to biogasI would recommend you to combine AD with MEC. Storage now is an issue, as it is extremely light and subsequently you must increase its density. Options that are usually applicable in industry are either high-pressure storage in the gaseous form, or very low temperature storage in the liquid form, or hydride-based storage in the solid form.

Hope this helps a bit

Evangelos

Ya , it is possible to produce Bio-hydrogen in Batch tank reactor by Dark fermentation in anaerobic condition, plz mention what are the bacterial or fungal strain you are using

I will go in the same line with some of the aforementioned suggestions. Through the dark fermentation process, it is possible to produce H2 gas. However, unlike an anaerobic digestion process, you need to provide an acidic environment (5.0-6.0) in the bioreactor to enhance bio-H2 production. Besides, increase in partial pressure in the bioreactor has a negative effect on H2 production. You should go for a low working volume, use gas sparging techniques (CO2 or N2) or continuously release the gas produced. Additionally, the culture you are using for bio-H2 production is also important. If it is a mixed culture, the acidic pH is further important so as to suppress methanogens. You may also go for inoculum pre-treatment to suppress H2-consuming bacteria in mixed cultures although for large scales, these are not currently feasible.