FIBER FILTER BAG
INTRODUCTION
This summer, I joined the on-campus startup, Fiber Filter, which serves as a product-centered movement focused on decreasing microfiber pollutions in our oceans. We are currently in the process of developing a bag that prevents the release of microfibers from clothing into water flowing from laundry machines. This process requires extensive testing with various industrial mesh sizes and closure methods to optimize the percentage of microfibers captured. So far, we have been able to capture 87% of microfibers in one wash cycle with our Fiber Filter bag and are aiming to improve upon that capture rate. I joined the team as a designer to help with web design and data analytics to help shape the future of our product. I soon started working with the team on bag prototyping, as well. Here our some of the key outcomes of our product design process of the principal Fiber Filter product.
THE PROBLEM
Laundry machines are polluting our oceans. Every time you wash your fleece, or any other type of synthetic garment, it releases up to 250,000 tiny pieces of plastic. These fibers are too small to be captured in your typical washing machine filtration system, and even the country’s best wastewater treatment plant can’t stop these pesky pollutants. These days, it is hard to find a shirt or sweater that isn’t partially, if not completely made of synthetic material. This means that plastic fibers are flooding our rivers and oceans at an alarming rate, and the problem it is only going to accelerate as our fashion trends shift toward petroleum based textiles. Once these tiny pieces of plastic make their way into rivers and oceans, they wreak havoc on marine organisms. Often mistaken for food by juvenile fish and other small organisms, the fibers can interfere with their digestive systems by acting as an appetite suppressant, often having a fatal impact. Even if they are ingested by larger organisms, the fibers are problematic in the way that they transmit harmful chemicals. The plastic fibers are particularly good at absorbing Persistent Organic Pollutants, things like fertilizers and flame retardants that don’t degrade over time. These chemicals get absorbed in the fatty tissue of organisms and bio accumulate up the food chain, eventually getting to us. This problem by no means few and far between. A recent study indicated that 33% of the shellfish we buy contain micro-plastics, along with around 25% of the fish we eat. We are eating plastic and don’t even know it.
PRODUCT JOURNEY
Microfiber pollution is a newly discovered problem, which is astonishing given its scale. 85% of the plastic on global shorelines is made up from microfibers. But it means the solution space is wide open. We got involved in this issue through multiple points of impact. First, the Fiber Filter team was able to assess the problem in our local Washington DC community. Fiber Filter partnered with an organization called Adventure Scientists, and collected samples of water from the Potomac to send to them for study. The results they returned to us were encouraging - they found microfibers, but not a lot, suggesting that the local Blue Plains Wastewater Treatment plant lives up to its reputation as one of the best in the world. This provided Fiber Filter with one potential solution: advocate for the improvement of industrial scale filtration systems, because they really do have the ability to make an impact. However, given research showing prevailing extensive micro-fiber pollution in other regions, we were lead to a consumer solution to center our activism. With the help of a grant from Georgetown University's Social Innovation and Public Service Fund and generous mentors, Fiber Filter pivoted to develop an in-wash filter bag into which you put your synthetic clothes. It captures microfibers at the source, preventing them from reaching the waterways where they cause so much damage. Now like we said - it’s a new issue, so the solution space is wide open. Our idea is one of many with the power to mitigate the problem, but we think it’s particularly impactful for the way it gives the solving power to the consumer. All it takes is a zip of the bag and a toss in the wash (and the dryer too!), and the consumer becomes a solution.
METHODS
Our scientifically rigorous testing methodology has been refined over many iterations, and the current methodology is as follows. Fiber Filter built a testing apparatus: A 7.5 foot tube with an adjustable size ending and an adapter was connected to the washing machine by a turnkey clamp. When testing, we removed the effluent hose from a high efficiency washing machine, and replaced with a flexible rubber pipe, fixed with a turnkey clamp, which feeds into a 50 gallon plastic drum. The effluent is then pumped from the drum through a 150 micron mesh filter. These filters are weighed before testing, and after being dried in a desiccator, they are weighed again. The difference in weight is the amount of residue, including microfibers, which were released during the wash cycle. Each time we test a new prototype, we first run the washer 3 times, with no load or detergent, to measure the amount of residue released by the washer itself. We then test a piece of a brand new fleece blanket, identical to the one inside the prototype bag, in order to ascertain the weight of the microfibers released. Next, we run the washer to ensure no microfibers are left within the system, before testing the prototype itself. There are two main factors we are testing in prototyping the bag: the micron-size of the industrial mesh material and the closure method. The product itself is a very fine nitex nylon mesh bag, likely between 50-150 microns in mesh size, into which synthetic garments are placed. We have tested these two sizes and are currently attempting to discover the optimum sizing for microfiber capture. Our strategy is to find the largest micron-size mesh, that with the proper closure method could optimize our micro-fiber capture rate. This is primarily because the smaller mesh sizes both comprise the cleanliness of the laundry and are more expensive materials. Thus we are looking for the optimal mesh size that allows water and detergent to circulate around the garments but prevents microfibers from being released into the washing machine effluent. The exact closure method of the bag has also not been finalized, although prototypes have been developed using zip and drawstring closures. We also aim to develop a prototype using a fold-over seal, similar to the ones often found on waterproof bags.
CLOSURE METHODS
While we haven't finished testing closure, Fiber Filter's initial cost benefits analysis and prototypes of bags with various closure methods can be seen below.
Drawstring:
- Pros: Cheap, easy for the consumer, durable/reliable
- Cons: Difficult to get complete seal, may limit space within bag
Zipper:
- Pros: Cheap, standardized to delicates bag, very easy for the consumer
- Cons: Zipper may break, unreliable, fibers could get caught in zipper, causing problems, seal may not be totally effective thanks to gaps in zipper
Folded over, buckled
- Pros: Excellent seal, standardized to the seal of a waterproof bag (outdoorsy people being a key target market), reliable, unlikely to break, many ways it can be modified/ combined with other closure methods.
- Cons: Expensive, more labor intensive for consumer
INITIAL RESULTS
The testing was definitely a great learning experience, and it told us a lot about things that we needed to change overall in future testing. In the initial testing were unable to get definitive qualitative data about the efficacy of our bag, but we were able to see some qualitative data and ‘soft’ quantitative findings.
Our bag survived drying fully intact
Qualitatively speaking, we know that the bag does contain some microfibers as we were able to see them on the inside of it
In addition, it was plain to see many of the fibers were attached to the fleece itself. Perhaps removing it from the bag before drying would see these fibers captured in the lint filter of the dryer.
We were also able to see more red fibers on the filter used for the effluent of the wash of the fleece SANS bag than on the filter used for the wash of the fleece IN the bag.
The overall weight of the filters used for the effluent of the wash of the fleece SANS bag changed by a much greater degree (from before the wash to after it) than did the filter used for the wash of the fleece IN the bag. This is evidence that the bag does contain more microfibers, however there was additional debris on the filter besides microfibers and some water was lost during pumping.
From this experiment we discovered that in the future we will need
to change filters more frequently
to do a wash of the fleeces prior to the test wash
to standardize the fleeces so they are a uniform color
to get a new fleece (more than one)
to not use soap, or use a smaller amount
to bring our own extra bucket
to deliberately stain or dirty garments prior to wash to analyze whether the bag interferes with cleaning of garments.
to test at different temperatures
CURRENT ITERATION
After more than 40 wash cycles, the Fiber Filter team is still testing different bag designs and prototypes with various mesh sizes and closure methods. When testing a 150 micron mesh bag sewed around a fleece, a capture rate of 87% was recorded. With further product development and different mesh sizes, we are confident we can increase this number.
