Science Buddies: "Ask an Expert"

Biogas digesters have been widely used in the past by converting livestock wastes into usable energy. I was thinking of the same concept but replace livestock wastes with leftover food wastes. My project idea was unsuccessful because I realized that scientists have already discovered that idea. I've been trying to think of biogas-related topic (by using food instead) and I still haven't got anything yet. This is a very large concept and I don't really know how to break it down into a suitable study.
I know bleep gas is bad for the environment and people invented the biogas digester just to turn this gas into goods. Does this means that we should extract as much bleep gas as possible once it is inside the biogas digester, so that we can get more goods ?
Can we study on an alternate way to produce biogas by using different bacteria and producing different flammable gas ?
(I was thinking of yeast to produce alcohol and carbon dioxide)
Again, I'm still not satisfied with those ideas listed above. There are some factors about it that make it impossible to study. Can you please give me some suggestions on how to make my topic more accessible ? It's okay if you think I have to go for a total different idea.

Hi missybitsy,

Some thoughts:

Queries to either answers or google of either:

1. "leftover food wastes energy"
2. "biogas biomass science fair"

to either answers or google yield many suggestions.

Some notes:

1. Please excuse if you've already done the above.
2. Biomass is synonymous to Biogas.
3. That the project has already been done is not a reason to not do it again. (Anyone, please correct me here.)
4. I can't provide any guidance on bleep. Again, can anyone help here?