There would need to be a drainage field, doesn't matter how big your lot or yard is, septic's are used to hold solids not liquids. Think about it, how quickly would you go through 1000 or 1500 gallons of water, knowing a typical shower you use over 40 gallons.
The field would most likely consume your entire front yard.
My neighbor had his entire front yard torn up to about 3 ft in depth, several tons of gravel, lots of 4 or 6" PVC pipe, etc etc. Took 3 guys about a week to complete the project with dozzers, back-hoe's etc etc. The going rate in MI is about 10k depending on the size of the field obviously, this field was about 200' x 60'
I have one 1500 gal tank, 4 person household, lasts roughly 2.5 - 3 years, costs about 200.00 to clean it out.
Go read the wiki
http://en.wikipedia.org/wiki/Septic_system