Yes but then aren't you polluting the water? Where are you going to dump the water? Recently legislation was passed to ban micro particles from abrasive soaps and creams because they ended up in the water supply from people flushing them down the drains.
"Microbeads" are generally from 10 micrometers to 1 millimeter in diameter. [0] Ultrafine particles are less than 100 nanometers in diameter. [1] So while there could be environmental effects from ultrafine particles, the analogy to microbeads isn't necessarily correct.
See: http://www.npr.org/2014/05/21/313157701/why-those-tiny-micro...
This does not seem like a real solution, it only moves the problem somewhere else.