Here I have included some websites on the subject, I would suggest getting the land evaluated for a septic system. There are many facters to consider when installing a septic tank. Drainage, soiltype(for absorbtion), also local regulations and if you live near a body of water they may have certain rules to follow. My brother had to go by the Neches River Authority and install a drip irrigation, but this is probably not your case here. Call a local plumber and find out who to contact about getting the property evaluated for a septic.
Q & A's on septic systems - http://www.midcoast.com/~compost/septicinfo.htm
A manual on septic systems in adobe- http://www.state.nj.us/dep/dwq/septicmn.htm