What did we do wrong in our bio diesel synthesis?

This is for an experiment and not for a practical batch, but we took 100 mL of used oil and 40 mL of ethanol (specifically it was distilled everclear). We took off the top layer which we were pretty sure was bio diesel but now we're not so sure. We got about 25 mL of good, filtered "bio diesel". We added 5 mL of water on our professor's instructions. He said it was to get out any remaining fats or something like that, and we just had to wait 5-30 min. It's now frustrating when he tells us he didn't really know what he was talking about because nothing separated. Any guidance? Should we let it separate longer? Should we remove the water somehow? Could we heat it out? Is it still good (if untested) biodiesel? There is very small solid particles at the bottom if that helps. by the way, we have 5 samples so we're welcome to try some things.