I have researched the following methods and am practising the Cat Litter method in my studio.
If you have any other methods for safely disposing of Acrylic paint I would be interested to hear from you. This is a topic that is not going away and should be a concern for anyone using this wonderful medium.
It is worth noting at this point that with any of the methods shared below, the amount of water that you use in your brush cleaning jar, and/or paint mixing jar should be limited to 2”.
In all instances, artists should wipe their brushes and palettes on paper towels and rags before rinsing in the water to reduce the amount of water used. All brushes can be cleaned in 2” of warm water with Conditioning Soap and then rinsed out in 2” of cold water, then dried on kitchen towel. These paper towels will be put in the bin for proper disposal in the landfill.
Pigment Disposal Process
This method of filtering is recommended by Golden, a leading manufacturer of Acrylic paint. There is a link to a Youtube video in the title that shows this method of extraction.
This process uses a chemical reaction called flocculation to separate the water and the pigment.
Once the clear water is skimmed off the top, the pigment is filtered and the filter is disposed of in the trash. This process cannot be used with toxic paints.
It uses common garden chemicals which are hazardous so read label precautions.
Gloves should always be worn!
- Dump your waste water into the 5 gallon container in the studio filling it to either the one or 2.5 gallon level. 2.5 gallons is the maximum that can be processed in the 5 gallon container.
- Using the glass jar, mix the proper amount of aluminum sulphate into the jar, add a few ounces of clean water and mix thoroughly. For one gallon, use a well-rounded half Tablespoon. For 2.5 gallons of water, measure 1.5 Tablespoons. Pour into the waste water and stir vigorously with a wood paint stick.
- Add the proper amount of powdered lime and stir vigorously. For one gallon, this is a scant 3⁄4 Tablespoon. For 2.5 gallons of water, measure 1 3⁄4 Tablespoon lime.
- Within a few minutes, flocculation of the solids should begin to occur. You should start to see a clear layer of water forming very quickly as the solids settle to the bottom. If, after several minutes, flocculation has not occurred, repeat steps 2 and 3.
- After the solids have settled, scoop off as much of the clear water as you can, using the pitcher, and pour it down the drain or outside.
- Assemble the filtering equipment as follows: Place TWO coffee filters in the metal funnel and put them over another empty 5 gallon container. Pour the remaining dirty water onto the filters after flocculation has occurred. After the dirty water has been poured through the filters, the water in the 5 gallon container should be clear. If it is not, pour less into the filters in steps and let it filter through before adding more dirty water.
- Place the used filters into the garbage can with the other waste going to the Landfill. The clean water in the 5 gallon container can now be poured outside on the ground or down the sinks.
Cat litter method
- Fill a bucket with non clumping cat litter
- Pour wastewater into the litter and wait for the solid acrylic particles to be absorbed
- When the litter has reached absorbent capacity Dispose of litter as Landfill Waste method (Black bin liners).
This is pertinent if you use a lot of waste water in your artistic process or maybe belong to an art community or shared space.
It also relies on access to sun as the heat from the sun will evaporate the water.
It is important to remember to limit your brush cleaning water to 2” in a jar. Any more than this will render this method of filtering obsolete as it relies on the water evaporating from the sand .
- You will need a large container (e.g. an old oil drum) with sand in.
- Make a small ‘well’ in the top of the sand – this is where you pour your water
- Pour your waste water into the ‘well’ and turn over the top of the sand making sure you make another ‘well’ for the next user.
- Stand the container of sand in the sun with the lid off for at least 6 hrs a day.
- Make sure the lid is put back on at the end of the day, or if it is raining!
Over time (this method will keep viable for years and years) the amount of acrylic particles in the sand mixture will be such that you could use it to make a sculpture – just mix with the right amount of concrete mix and voila!!
Solo Artists not using much wastewater
If you do not use enough water in your acrylic artwork (if you practice the ‘Pouring’ method of acrylics for example, then you could absorb the acrylic paint using old rags and paper towels and dispose of it with the normal household waste.
Any washing down of equipment however, should also avoid any acrylic particles getting into the water system, so one of the above methods should be used for that purpose.
If you use Acrylic paint let me know how you dispose of your wastewater.
Do you just put it down the sink or do you worry about environmental impact?
Do you have another method of disposal?
I would love to hear from you.