I actually work in the wastewater industry and from what I’m reading, a properly functioning sewage treatment plant already captures a very high proportion of microplastics. This widely cited study noted above 98% removal efficiency at one plant.
We’re already at approaching 2 log (99%) removal without actually trying to. It doesn’t seem improbable to me that with a few relatively modest tweaks to the system we could get 3 log removal (99.9%). Getting to 4 or 5 log removal is likely where things will get really expensive and challenging. But for now, a 2-3 log removal is probably good enough to focus on other sources like tire fragments/dust that typically pass directly to receiving waters with no treatment at all.
Guy I worked with retired from the Navy as a captain and got whatever very generous pay came with that. Then used his veterans preference to get a job in my agency, did that for 20+ years, retired as a gs 14 so he gets that annuity plus his TSP savings plus social security in a few years. He’s still barely 60, so he is working as a consultant. I’m guessing he’s pulling down $200k with all the various incomes and maybe working 20 hours a week, and he’s got the Healthcare and other benefits for life. People trash talk the military and government but if you work the system right it can be worthwhile. Hell, I wish I’d joined just so I could get USAA.