[dahfizz]

I imagine they use the same chemicals as marine toilets / portapotties. It breaks down poop and toilet paper into a liquid so that it can be pumped / emptied easily. Not sure why the article focuses solely on urine...

[mattmaroon]

Those chemicals don’t liquefy solid waste instantly. They won’t be very effective in the timespan of a flight.

Most likely they use a macerator pump that accomplishes it physically and instantaneously.