Introduction: Microplastic Filter for Washing Machine

Depending on what kind of fabric your clothes are made of, you may find that the wastewater from your washing machine contain a lot microplastics! For Norway, it is estimated that approx. 110 tonnes of microplastics are released into the ocean from clothes washing alone. This instructable is an attempt to make a DIY solution that you can use to filter the water from your washing machine, using almost only everyday household items. It also contains a way to get rid of the microplastics from the filter.

The picture is from a test wash of a red children's fleece sweater, and it is less than 1 mm in length!


Some of these items can be used before

  • Liquid container (more than 5 L)
  • Fine mesh (about the same size as the bottom of the container), I am using one of aluminium that can be laid dobbel.
  • Filter sand (you can get filter sand from a pool supplies shop or at your local swimming pool!)
  • Tubing
  • Box that can fit the liquid container
  • Knife
  • Drill

Step 1: Prepare the Bottom of the Tank

Turn the water container upside-down and drill holes in the bottom of the tank. You will need a lot of holes to be able to filter the water faster than the washing machine fills the tank.

Step 2: Make Slit for the Filter Mesh

Put the container on the side and cut a long slit along the top, to be able to fit the filter mesh into the container.

Step 3: Insert the Filter Mesh

Insert the filter mesh and make sure that it covers all the holes in the bottom of the tank.

Step 4: Put the Container Into the Box

Fit the liquid container into the box and use a tap or attach a garden hose to lead the water into the sewage (it may be necessary to have a hose with a wide diameter). To fit the hose, you most likely has to make a hole in the box and then you should make it some centimeters up from the bottom on one side. This way, you prevent that some of the sand end up in your hose and make it clog up.

Step 5: Put in the Sand

Put in a good amount of sand, into the liquid container. The more the better.

Step 6: Test Wash

Put the wastewater pipe from the washing machine into the opening of the liquid container. Then you can start your washing machine and run a test wash to make sure it doesn't flood your floor.

In the video the box is standing on the washing machine, but it is smarter to have it on a stool next to the washing machine until you know it will not flood your floor. Also, sometimes the centrifuge can make the washing machine shake so that things on top of it will fall down.

Step 7: Getting Rid of Microplastics in the Filter Sand

Getting rid of the micro plastics in the filter sand can be difficult. We did this by using a kitchen stove with a pyrolysis program. This completely incinerates the micro plastics and only leave ash in the sand. Although the gases can be toxic, or the burnt products may be harmful, it is a good way to get rid of the plastic. It can be done by scooping up the sand from the liquid container and put it into a baking tray. Put the tray into the oven, and run the pyrolysis program. The sand can be put back into the container afterwards. The washing cycles rinses the ashes out of the sand afterwards.

Step 8: Tips!

  • To make it more effective you can put the container on av small stand in the box, making the water run through faster.
  • If the container is elevated above the outlet in the box, water will drain out of the container between washes, so that the sand dries up. Then the sand will smell less.