Regarding this letter: Sanitation Issues: Understanding Home Septic Systems , I have a few observations:
When our family recently took a vacation to South America, we were instructed to throw all toilet paper, wet and dirty, into a waste can – even at the best hotels. By American standards, we found that pretty gross.
I read that this is standard in many countries and greatly reduces the need for septic tank pumping – to once every 10 years instead of the recommended four years. Although pumping is expensive, about $400 when we last had it done, that is a fraction of the cost of replacing a clogged leach field.
We have long put the wet toilet paper in the trash, which is emptied weekly. It does not smell.
We also have a screen for our kitchen drain and avoid using the sink garbage disposer for any but the smallest particles of food. And we \also dump/wipe out grease from pans and scrape dishes thoroughly into the trash.
There is a US EPA web page  that has good visuals to know how your septic system works.
Thanks, – B.L. in Colorado