Uses for waste water from rendering?

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Mad scientist
Jun 11, 2019
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People who render your own lard/tallow/etc, do you have any uses for the waste water? I hate to waste anything and after taking the solidified tallow off the top, there remains a quantity of water which clearly has a lot of fat dispersed in it. Given the salt content I can't give it to the animals, so I'm looking for a better option.


One thing which occurred to me, but I'm not sure if it's realistic, is to add a small quantity of lye and treat it like an old style boiled soap. My theory is that the part that could be saponified will be, and the remaining impurities and excess lye will stay in the water, which could then be put down the drain without fear of clogging it.

Is this a great idea or a stupid one? 🤔

(hope it's ok to post in this forum section, it seemed like the best fit, but if not please move!)