cleaning IBC totes

I've got a line on some free IBC totes that I want to use for rainwater and greywater projects. only trouble is that they held water-based drywall primer and there's some residue left in them.

so my question is how to clean them. it should be relatively easy to rinse the primer out, but I don't know what to do with all that wash water. typical advice is to let paint dry then put it in the garbage, but I don't think that will work in this case. I could open the totes up and let the primer dry, but I don't know how I would get it out after that.

so, any ideas?

Could you run the rinse water through a series of filters and let it sit for a while to evaporate anything else off, then just discard the filtering material and dump the water where it's not going to come into contact with food?  Or are there too many persistent/ toxic chemicals in it?  

Depending on how many totes you have, you could open one and let it dry, then see how much primer flakes off/ can be scraped off.  Or scoop some of the residue out and smear it on plastic with a similar texture to dry, kind of like a swatch test.  Edit: my thinking is that if it flakes off, you can just wash out the flakes (dislodging some with a hose/ pressure washer/ stick/ bent wire as needed) and filter that water.

Best way we've found is to dump in a bottle of dawn dishwashing liquid and fill with water. Let sit for a while then drain. Refill with water adding a box of baking soda and you should be good to go ... but if you have stuff stuck to the inside I'm not sure other than taking it to a carwash and spraying it down.

reasonable ideas. thanks. I've gotten a few more totes since I posted this, but haven't cleaned any of them. one was previously used for fermenting cider, so that one shouldn't need much (if any) cleaning.

Hei Tel

I've been advised to ensure all microbial life in the IBC totes are gone due to the risk of things growing in your catchment water when the sun hits it. I wonder if the fermenting may leave any microbial life in the tote. Maybe being dry for a while took care of that. I'm actually going to paint my totes black to keep light to a minimum. But, I will be sterilizing the totes because they will water my chickens and the drip lines in our high tunnel. The tiny emitters would get clogged up easily if stuff started growing in the water. Just a thought.

By the way, I used to live in the greater Helsinki area (Espoo) when I worked for Huhtamaki. I enjoyed living in Finland. American city design and planning have a lot to learn from Espoo.

I also plan to paint the totes I use for storing water, but it will all run through a slow sand filter before it's used. I might use one or two totes for greywater as part of a sort of living machine, in which case growing things in it will be part of the design.

haven't been to Espoo (or even Finland), but I've got family in Pihtipudas in the middle of the country. it's on my list, not least for the urban design, which seems to be getting better while we're still getting worse.