Lint trap fiber efficiency evaluation

Two commercially available washing machine lint trap models, Filtrol^© (WEXCO, Milaca, MN, USA) and Lint LUV-R^© (Environmental Enhancements, Dartmouth, NS, Canada) were evaluated for their ability to remove textile fibers shed during home laundry. Fiber capture was quantified for three filter pore sizes in case of the Filtrol^© model (50 μm, 100 μm and 200 μm), and two pore sizes for the Lint LUV-R^© model (150 μm and 1588 μm). Both filter models were tested using two types of textiles: i) polyester fleece and ii) nylon stretch woven. Replicate washes for both fabrics were run with all mesh sizes, except the two largest meshes (200 μm and 1588 μm) for which nylon fiber retention was not assessed.

Laundry effluent downstream of the lint filter (the lint-filter filtrate) was passed through a 10-μm stainless-steel conical filter (S2 Fig in S1 File). The lint retained by the candle filter (a cylindrical Hop Randall filter with a height of 33 cm and diameter of 12.7 cm with 10 um stainless steel cartridge was used) and the lint captured by the lint filter was then separately collected using the 20-μm vacuum-filtration and weight as described in section 2.3. Lint retention was calculated for each combination of mesh size and textile type as a weight/weight percentage of lint retained by the lint filter versus the total mass of shed lint, both recovered from the lint filter and the filter filtrate, as below:

Additional tests were run to compare the two sampling methods: (1) the candle-filter method for processing the entire effluent, used for evaluating lint filters, and (2) the manifold method for sampling 1/8 of the laundry effluent, used for evaluating textile shedding. For three washes, 1/8 of the laundry effluent was collected using the manifold, and the remaining 7/8 were processed with the candle filter. The two samples from each wash were used to make separate calculations of the total lint from the wash, and the results were compared. The lint mass calculated from using the candle filter was on average 14% lower compared to the mass calculated using the manifold, indicating that sampling method is yet another source of variability potentially affecting inter-comparability of textile shedding studies.