Hi all,
I have been making small batches of biodiesel using cavitation to heat and mix the vegetable oil with methanol and caustic soda. Its worked well, giving a really clean product.

My next challenge is to use raw sewage to make biodiesel using a cavitator.
Has anyone done anything along these lines before?
Any advice is much appreciated!

Sewer gas is methane. Microorganism interact with sewage to produce the gas. You might be able to make methanol from methane as part of the biodiesel raw materials. The process of making the methane might be called anaerobic digestion of sewage. It was being done in Africa a few years ago.