At Formlabs, we go through a very large quantity of IPA as you can imagine 
We use solvent distillers from this company to minimize our waste http://www.uniram.com/solvent_recycler-auto.html. Note that these solve the sludge problem by evaporating the input solvent in a one time use plastic bag.
I hadn’t seen these low cost distillers meant for moonshine before. If it works well for you, please let us know, as we may recommend it to our customers.