To remove plastics from the oceans the best solution is to not put plastics into the oceans in the first place. The biggest source of micro-plastics being our washing machines it makes sense to remove these plastics from the wastewater coming out of our washing machines.
We experimented with many different filtering materials from wire screens to cloth cut out from used clothing. One wants to catch as many fibres as possible, but one also don’t want to change the filter after every wash. It’s best to find a balance between catching the most fibres and changing the filter at intervals that is convenient for you.
Fine or dense filter materials trap a lot of fibres, but that also means they can clog up quickly. Dense fabrics such as ones used for clothing or bed sheets can clog up in less than one load.
Several layers of course filter material with openings approx. one millimetre wide works the best. When layered together each layer may not catch very much, but multiple layers of course material work as well as one layer of fine material. This setup lasts longer, meaning you don’t have to change the filter all the time. The three kinds of filter material that we’ve found to work well are pre-made washing machine lint traps, filters made from plastic luffas, and cheesecloth.
The first thing you need to determine is whether your washing machine empties into a laundry tub or directly into a drain pipe. If it empties into a tub then the solutions are very simple and are outlined below. The first two solutions are filters that clamp onto the end of the washing machine hose and the third one lets the water drain into a filter container. If the hose from your washing machine connects directly into a drain pipe or a laundry box in the wall then it’s a little more complicated. A contained filter unit has to be made which goes in between the machine drain hose and the drain pipe. This unit has to be watertight for obvious reasons. The design for this filter unit is outlined last, but the filter that goes inside it is the same as the first two below-the lint trap or the plastic luffa.
Pre-made Washing Machine Lint Traps
These can be bought in bulk for about $1 per piece. These are made for people who have septic tanks. As plastic is bad for septic tanks, these are meant to remove plastic lint from laundry wastewater. These are merely attached to the end of the drain hose with a reusable plastic tie. We’ve found that one can easily nest three of these inside the other, increasing the effectiveness. You’ll have to monitor this to make sure you change it before it clogs completely and possibly causing damage to the washer. One of these can last for one to two weeks. Your mileage may vary.
The idea here is the same as that of the lint traps mentioned above, but you make these ones yourself. Instead of throwing out old luffas you can put them to use! Plus they’re very cheap. One luffa can yield a tube of filter material more than three meters long, enough to make about ten triple layered filters.
In the middle of every plastic luffa is a plastic tie that holds it together. Simply cut this and you’ll find that the luffa is made up of one long sleeve of plastic weaving. To make the filter, reverse one end of the tube back onto itself by about six inches(15cm). Use a twist tie or plastic tie to cinch the tube where the original end is now. Reverse the new open end over the sleeve. The cinched end is now the closed end of the filter. Cut the top end from the rest of the tube. Now you have a three-layered filter that you can tie onto the washing machine hose.
This is the simplest design and is our favourite. It also uses a cotton material that theoretically will decompose over time. The idea is that water from the washing machine will drain into a container that is covered with a filtering material. Water goes through the filter and out of drain holes in the bottom of the container.
Use a plastic flower pot or small pail with drain holes cut into the bottom. Form a bowl with about six layers of cheesecloth and clip it to the container with plastic clips. The drain hose drains directly into the container. With this setup, if the filter clogs completely the water merely overflows, avoiding back pressure and possible damage to the machine. Make sure the end of the hose is above the rim of the container to prevent possible syphoning of wastewater back into the machine.
Filter Unit Made From Whole House Water Filter
This solution is for those whose washing machine drain hose goes directly into a drain pipe or wall box. There’s no laundry tub or the wastewater bypasses the laundry tub. This setup will cost about $80 worth of materials from your hardware store. The materials are a whole house water filter, a rubber washing machine drain hose, two 3/4″ thread to half-inch pipe adapters, two hose clamps, and whatever hardware you may need to mount the filter unit to the wall.
First, find a place on the wall in between the machine and the drain pipe for mounting the unit, the closer to the drain pipe the better. Mount the filter unit onto the wall with the “in” opening close to the drain pipe. The filter unit will work in reverse as the wastewater will be entering the unit through the middle opening of the inside. Screw in the two threaded adaptors.
The curved end of the rubber drain hose is designed to hook into drain pipes. Determine how much is need to reach the unit while the curved end is inserted into the drain pipe and cut there. Attach the cut end to the pipe adapter with a hose clamp. Make sure the clamp is right at the end as close to the adaptor as possible as the there’s not a lot of material to clamp to.
From what is left of the rubber hose cut off approx three inches(8cm). This will act as a way to attach the filter onto the water outlet inside the filter.
Use the leftover section of the rubber hose to attach to the washing machine water outlet. The flared end is designed to fit the attachment point on the back of the machine. Clamp the other end to the adapter on the filter unit. This in point should normally be the “out’ of the filter as we’re reversing the flow of the water filter.
Using one of the filter designs mentioned above and attach it to the short rubber hose section with a plastic tie. Slip the hose end onto the water outlet in the middle of the top section of the water filter unit. I choose to not insert this too tight so that if the filter becomes too clogged then the hose can merely pop off with the pressure, avoiding damage to the machine. I also do not clamp the filter to the short rubber hose section tightly for this reason.
With the unit assembled do a test for water tightness. The rinse cycle is handy for this purpose.
Please Give Feedback
We’ve tested these designs to make sure they work, but extensive testing is beyond our abilities. So please tell us how well these designs work for you and whether you have any suggestions. You might even have better designs of your own to share!
Remember that while filtering is one solution the other solutions outlined in the previous blog can be done concurrently and are easy to do.
We might not be able to completely remove all of the plastic lint from our washing machines, but if we all do a little, it will make a significant difference.