Actually, based on how I understand our septic system to work, I believe it is a very good method of handling human waste.
Our system is completely enclosed system. All waste is delivered to a dual chambered sealed tank. All solid matter settles in the first chamber where bacteria consumes it and the liquid overflows into a second chamber. From there, the liquid is pumped to an above ground mound where it is able to leech into the soil.
The advantage I see is that most of the water we pull from the aquifer is returned rather than evaporating into the atmosphere. City systems have open ponds where the water evaporates rather than returning it to the aquifer where it originally came from. Our aquifers are taking quite a hit from our wells, roadways, buildings, parking lots, etc. and water supply could become a serious problem eventually.