Assuming that the soil ...

Assuming that the soil conditions are not all sand and have some type of blend of clay and other materials why not utilize land application for the treatment of regular human waste/wastewater. (if you google Land Application of Wastewater) it will give you the required soil conditions for this treatment method). This method would recharge the nearby aquifer. To treat the ground water in the aquifer for drinking may I suggest an ultrafiltration system. These systems are now modular and provide good consistent water quality. May I also suggest duplicity in design so that backwashing of the unit and other maintenance activities can occur on a regular basis.

Regards,

Gary