One other option is an aerobic septic system http://www.thecleansolution.com/. This is a new variation of several systems used over the years in problematical sites with poor or insufficient soils. They can be quite effective but generally require electricity and usually monitoring to operate. I believe the state of Maine was approving these types of systems for ocean front lots with existing buildings that had failed systems or straight pipes. Unlike a conventional leachfield where the bulk of the biology is going on at the individual weep holes of the piping, the majority of the biology is going on inside the media chamber with an aerobic system.
The Presby design leach field has a mesh media wrapped around the corrugated distribution piping which is then covered with geotextile, it acts as a poor mans trickling filter as the media forms far greater surface area for the bacterial mat.
The aerobic technology has been around for years and usually is referred to as trickling filter. One plus is that anerobic conditions tend to be far more aggressive to concrete than aerobic conditions so tanks should last longer. Note most municipal treatment plants are aerobic based.
The Presby design leach field has a mesh media wrapped around the corrugated distribution piping which is then covered with geotextile, it acts as a poor mans trickling filter as the media forms far greater surface area for the bacterial mat.
The aerobic technology has been around for years and usually is referred to as trickling filter. One plus is that anerobic conditions tend to be far more aggressive to concrete than aerobic conditions so tanks should last longer. Note most municipal treatment plants are aerobic based.