[Christ]

Glycerine. That's all.

And making BD is only as harmful as the operator lets it get. Methanol is no more dangerous than gasoline, and people store large quantities of gasoline in thin plastic containers, isolated from any source of ventilation and often in direct sunlight.

Sure, lye is caustic. So is Drano.

The 300TD I believe has an IDI engine, and regardless of that point, it's old enough that it doesn't need a complex fuel system. Newer vehicles require intense filtering and basically bullet proof fuel systems because of the ECU-controlled components and exact standards to which they adhere during operation.

As far as selling soap, yes. I used to breed sheep, and soap can be made from lanolin, which is extracted after carding/pressing wool. It requires potash and lye, as well.

Throwing glycerine soap in a landfill is still far better than letting it hang in the air. It breaks down rather quickly in the environment, providing sugars for bacteria, which speed the degradation of trash, producing a controllable source of pure methane, which can then be used to make methanol, which is then used to make more BD, etc. It's a logical circle,actually.

Glycerin, as I pointed out a few posts back, also has uses in medicine, farming, and personal hygiene. The amount of soap produced is a component of the operator, not the batch. Soap production can be minimized with proper titration techniques, the excess methanol can be washed from the batch and recycled back into another batch.

Dumping vegetable oil can be a problem, but usually isn't, as long as it's done responsibly. Bacteria can break it down fairly quickly, making it less harmful than bubble gum, actually. (I've never tested that, it came from a meeting I attended at a local landfill, so it could be complete BS.)

The base waste component of BD is glycerine, raw. The particulate emissions from WVO/SVO contain triglycerides, a compound form of glycerine, which is harmful. The methoxide brew breaks down the glycerine from the chain and replaces it with methanol, making it fairly inert.