Thank you for pointing out these important aspects to methane digesters. How can fires be avoided and is there a way Hydrogene Sulfide levels can be regulated?
Haven't heard about the ones in China in the 70's. I wonder why that went out of practice. Was that during the Great Leap Forward? I can see how a great idea could be ditched because it was introduced together with something that could not work, like backyard furnaces. Or maybe I'm completely wrong, but would love to hear it still.
It sounds like you've had seen or maybe even worked with some digesters. Would love to know more about it, what aspects you liked, what not, and why. :-)