Removing Plastic Microbeads

We are an elementary Robotics team. This year, our theme is hydrodynamics. After extensive research, we have found the problem of microplastics. Microplastics are in all of our drinking water. Because microplastics are very small (the size of a sesame seed or smaller!) they can actually evaporate with water. Then, it rains microplastics, and it gets in our drinking water by a) traveling through sewage or b) raining directly into drinking water treatment plants. Microplastics being tiny can cause problems here, too, because the microplastics are too small to be filtered out in the filters already in water treatment plants! We have come up with a solution, but we are still trying to find a way to make microplastics �ball up� or stick/attract together IN water. If we do this in our drinking water treatment plants, we will be able to collect the �ball�of microplastics with Robotics. Do you know of any way we could make these microplastics attract together? For example, can we use any chemicals or other substances that WOULD NOT harm the water? We would appreciate any feedback you have, and we would like for a quick response, as our competition is in a few weeks, and we still have to work on our solution.Thanks,The Robotics Team
- Wendy (age 49)
Suwanee, GA, USA

From what I read, these beads don't usually get smaller than 10 microns. Although standard water system filters may let those through, many filters are available that would catch them. Getting them to stick together chemically is possible, but I think less practical than filtration. For example, changing the pH (not hard to do then undo) would lead to surface charges on the plastic, but that keeps the beads apart instead of clumping them together. I did some experiments long ago using biological antibodies to clump smaller beads that had been coated with antigen, but that's not close to practical for water filtration systems. 

Mike W.

(published on 11/09/2017)