Reduce water pollution: School Art & Design classroom
October 17, 2021 3:26 AM   Subscribe

I teach Art and Design at a Special Needs school, my classes are small, however I'd like to reduce the amount of dissolved paint and ink going down the drain. I currently have the opportunity to upgrade the wash area in my classroom; I'm looking for any ideas that can help me redesign the system to introduce better environmental cleaning practice.

My school has agreed to replace the small basic sink and wash basin I have in the classroom. I'm wondering how I can use this opportunity to create a cheap system for filtering water contaminated with paint and ink.

It would ideally be a system linked to the wash basin, reducing the need to move things like buckets around too much.

It would also have to be easy to use; it would be great to involve my students in its management, as I already have way too much classroom management to do.

What we do in my classroom:
- We paint with acrylic paints and inks
- We print on fabric using acrylic paints and fabric paints using basic processes such as lino stamps, and some screen printing using paper stencils.

Recently I considered upgrading our screen printing to creating our own photo stencils, but my research showed me that this would result in way too much chemical and water use for my peace of mind (Cape Town where I work has recently undergone a severe water crisis).

So far I've decided to install an under sinka sediment trap. They aren't cheap, but you can make them yourself.

I'm already following these guidelines:
- Don't overstock on materials
- Remove as much paint and ink as possible from tools and surfaces and dispose through solid waste disposal

However I'm keen to see if it would be possible to filter contaminated water. There are processes which involve chemical treatment such as using aluminum sulfate and powdered lime to cause paint in the water to flocculate (solidify) dissolved paint. I'm concerned with the use and storage of these chemicals in my classroom.

And there are diy ways to filter water and then allow it to evaporate, however I'm concerned this will be difficult to manage on the long term.

I would appreciate any ideas. My classes are small, however I want to decrease the impact on our already polluted water resources.
posted by BrStekker to Education (6 answers total) 3 users marked this as a favorite
Could you use water based paints like watercolor and gouache instead of plastic based acrylics?
There are some other environment friendly materials for many techniques, they might be not so lightfast as to garantee not to fade for 300 years, but do you really need to make everything to last for that long in your class?
posted by Oli D. at 7:58 AM on October 17, 2021

Two oddball and maybe impractical ideas. Phyto-remediation of soil via plants is a thing, could you have potted plants in containers that would fit into the new sink and have students wash hands/brushes into the potted plants? There are DIY (drinking) water filter set ups -- would a paper coffee filter work (to be swapped out after every class) to catch the paint and ink residue? Or a sponge?
posted by spamandkimchi at 9:06 AM on October 17, 2021

Best answer: Can you get a top drain sink? It's basically a basin that always has water in it and drains from a pipe on the surface of the water. It helps any solids sink to the bottom and keep them from going directly down the drain.
posted by Ferreous at 9:45 AM on October 17, 2021

Response by poster: Oli D. Yes, water based paints don't contain solvents which is a good thing. I use acrylics which are all water based and suitable for printing on fabric. Unfortunately the pigments in all paints, including water based can be toxic or unsuitable for release into water supplies.
posted by BrStekker at 9:49 AM on October 17, 2021

Best answer: In a clay studio where it's essential that clay not be swept down the drain when washing hands or cleaning tools, we have a couple of pans nestled inside each other, with drain water spilling over the top into the next pan, and finally we have a fine mesh over the actual drain. Tools and hands are dipped into the smallest pan (#1), and when that is full the run-off slops over the top into pan #2. Pan #1 has higher walls than pan #2 so that the only water going into #2 comes from #1 when it is over-topped. Allow everything to settle. Slowly pour off the clearest water from pan #2 into the sink to be sieved by the drain mesh. Then wipe out what settled on the bottom with a disposable towel or old newspaper (what I use). Then pour the clear water from pan #1 either into pan #2 or into the sink, depending on whether you think there are any solids suspended. Repeat as necessary. The only water from the tap goes into pan #1. A top-drain is another solution, but you are left with muck on the bottom that has to be cleaned, and removing it will be nearly impossible without removing the drain pipe, which will wash some of the muck down the drain. The overtopping pans solution is also very cheap.

I've also worked in screen-printing and find that a spray bottle with water sprayed aggressively on the screen, which lays on dry newsprint, scrubbed with absorbent toweling from the inside and then sprayed with undiluted "Simple Green" non-toxic cleaner and scrubbed again removes almost all of the ink. This is combined with careful scraping of the ink from the inside of the screen frame using an old credit card. There is almost no ink left to wash out. Speedball, the ink manufacturer, also makes a non-toxic screen-cleaning substance called "Speed Clean" I have found to be very helpful after using stubborn stubstances like drawing fluid and liquid blockers that are otherwise very difficult to remove. Spraying and scrubbing with towels works well, and then a final scrub with a soft carwashing brush and dilute dishwashing fluid complete the job. A pressure washer will make the most of limited water, which can again go into the sink with pans #1 and #2.
posted by citygirl at 11:25 AM on October 17, 2021

Best answer: Some municipal sewer treatment plants authorize the disposal of paint wash water. Before you go to the effort and expense, I would check whether it is necessary. Otherwise, follow the advice from there. If you aren't willing to use those flocculants, then you won't reduce much. They're non-toxic but less safe than wheat flour and I wouldn't let kids play with or potentially eat, but I'd let a supervised kid scoop and dump them or be in contact with the treated water.
posted by flimflam at 12:31 PM on October 17, 2021

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