Whenever I've read articles on people using biomass for biofuel there's always some paragraph in there about how the cost of biomass and the process makes the whole system somehow not cost effective vs. fossil fuels. This has never sat right with me. Aren't there literally rivers of biomass beneath every single city on earth? Aren't we currently PAYING to have these treated and swept away? Isn't the veritable "horn of plenty" of biomass right beneath our feet? How is it possible that fossil fuels can be cheaper than a process that uses something that's FREE as an input?
Well, it turns out that I don't know everything there is to know about cleantech. With no background in biology, or chemistry, or poop, for that matter, it seems that I have overlooked a crucial issue with using waste-water and turning it into bio-diesel:
It's really easy to make alcohol from sugar-rich substances (like corn) and then mix that with other oils to create diesel. This is the method used by most ethanol-fuel co-generation plants. But the process of having to add oils and mix it into something suitable for a typical internal combustion engine really screws up the economics of the equation.
Secondly, there isn't enough sugar-content in human wastewater for typical bacteria to even make the ethanol you want, so you're stuck having to use uxpensive feedstock (like grain), which further ruins the economics.
So, being able to actually create diesel without the need for those other oils, AND, being able to do so with a free feedstock like human waste could turn this industry on its head.
These folks have figured out how to breed yeast and bacteria derivatives that create fats, that through a few steps of esterification can be directly turned into bio-diesel.
They have also greatly reduced the amount of sugars needed in the process. Meaning that most of the feedstock can be human waste, with only a small amount of other feedstock (e.g. use grain from breweries) being used to top up the carbohydrate levels.
This is extremely promising work.
Obviously: "it's not yet at industrial scale" & "we can't compete with $2 per gallow diesel yet" but let's suspend our disbelief for a second, shall we, and celebrate the proverbial polishing of the turd.