SF building Yellow Grease to Diesel plant.
This makes more sense than having an independent set up a biodiesel plant, because this plant will always be functional. Governments can mandate that companies dispose of the yellow grease in their process. If an entrepreneur comes along, then instead of a tipping fee, folks who are trying to dispose of the yellow grease will start charging for their waste.
This flips the economics of the biodiesel plant upside down. Where once they could be paid for taking the feedstock, now they'll have to pay for the same material. And that could probably kill any margin for setting up the plant. If the local government forces the disposal of yellow grease through their system, this guarantees a continuous supply.
They might not get paid as much to haul it away as before, but it unlikely that the city will ever be forced to pay for the feedstock. Thus making sure the plant will always be operational.