I've been in my (new) home for a year now, and the LPP SandMound system was just inspected. I chatted with the crew for a while, it was interesting. He reiterated that washing machine output is the primary cause of failure, because:
1) The huge discharge of water stirs the tank(s)
2) Large amount of synthetic fiber is insoluble and ends up in the drain field (due to #1).
He didn't mention any filtering devices like the one you mention, but it looks interesting.
Older sand mounds systems failed quickly (5 to 8 years). New ones are much better (20+ years) because:
1) They are HUGE compared to old ones (mine is 100X10)
2) Two stage settling tank, catches more, ahem, solids
3) Rudimentary filter between second settling tank and the pump tank
4) Pump tank has large space at the bottom to catch any solids that get through (space below pump inlet)
He warned us against putting any 'feminine products' or wipes down, but primarily because they make cleaning the tank more difficult, not really because they hurt the drain field. The paper in these things degrades slowly, and can combine with grease in the 'scum' on the top of the tank and they have to chop it up with a shovel and get it out during cleaning. It slows them down.
I think these will continue to go down the pipe at our house.
We are required to pump every two years (by the County I think).
Anybody actually install that filtering device mentioned?
- Patrick W.