Sewage sludge is but one of many sources of hydrocarbons that presently are in an unusable form and given the right economic conditions could be converted into usable fuels that would compete in the marketplace with fuels from other sources.
The company that right now is converting the waste from processing turnkeys in Carthage, Missouri with their proprietary Thermal Conversion Process stated a few years ago that their pilot plant had successfully processed sewage sludge into liquid fuel roughly equivalent to diesel fuel.
Based on that experience, they (not me) estimated that if all the sewage sludge produced in the US were converted using their process, it would produce enough fuel to totally eliminate the need for foreign imports. Even if they are wrong by a factor of two or three, that is still a lot of fuel.
When that outfit [or anyone else using a thermal de-polymerization produce a hundred thousand barrels a day net [about one tenth of one percent of current oil consumption], give me a ping. Heck, when they produce ten thousand barrels a day gross give me a ping.
Some extremely large dairy farms are producing enough methane to run a few thousand houses. I applaud them, but I would like to reiterate: As full of crap as people [and cows] are, we aren't going to run our civilization on sewage sludge or cow manure.
Oil is simply a wonderful thing. Liquid. Energy dense. Producible in vast quantities at the price of a few thousand feet of 8 inch hole, casing and tubing. However, it won’t last for ever and the alternatives are all going to cost us. In your lifetime or the lifetime of your kids, the age of oil is going to end. Maybe very soon [my belief] maybe a few years in the future. Get over it.If you want to direct your optimism in a more realistic direction, try nukes, more coal fired electric generation, wind, photo voltaics, wind or simply more efficient consumption patterns based on higher prices.