I live in a small hamlet that uses a small treatment plant that ultimately runs off into a river. Treatment plants have gotten better, but after talking to residents, they are blissfully unaware of dos and don'ts of septic like systems. They are totally ignorant. Information is at their fingertips. I'm now worried about micro-fibres - from clothing etc. Most pollutants are avoidable but there are many available and it's easy to forget/ignore. Additives, cleaners etc. Not sure the swans are that impressed.