I used the NDS system in my shop,ran it wall to wall with a 4" line running out of each end.These go into a 55gal plastic drum (on each side),then I have 40' of 4" perf pipe laying in 2x2 drainrock trenches comming off of each one.There are 2 square floor drains also,one in my machine shop and one in the bathroom floor that are hooked to the system,and 2 utility sinks. The drums act as separaters and are the type with removeable heads for cleaning. The actual code in mi says you can only do this if the drainfield is within the footing,but since I have 3500 sq ft, that was not a problem.Anyway,the NDS stuff works great but requires a lot of time to "get right" before you pour. I built the whole drain system up on 2x10 reated that was set down first with the fall going 1/4"-4' each way.we then covered it all with good ole duck tape and poured the concrete.I'll find some pics and put them up tonight.