Re: In anerobic digestion, what is the chemical reaction taking place?

Dear Danial,

The water that collects in your gas receiver is from the high humidity of the gas as it issues from the genertor at a somwhat eleveted temperature. On cooling in the receiver, the excess water condenses and collects there. The only simple way to avoid this is to dry the gas stream (perhaps by the use of a calcium chloride tube in the connecting link), or pre-cool the gas to a lower temperature than it will encounter in the receiver, which in a cooler climate could be by simply passing the gas through bottle outdoors before collecting it.

As to the source of the methane, this arises by microbial disproportionation of the sugars, proteins,fats and whatever else is metabolizable in the manure feed stock. In disproportionation, part of the nutrient is oxidized to carbon dioxide, and another part is reduced to methane. The detailed reactions involved depend very much on what specific nutrient is being consumed and can be very complicated.

A bunsen burner would easily operate on a good grade of bio-gas, but beware! The gas in your collector may also contain air and the mixture of air and methan can be explosive so approach this cautiously, preferably outdoors and away from people and flammable materials.

Best of luck with your environmentally significant studies.

J. R. D. McCormick