I would be interested in any comments and/or thoughts you would have regarding the use of wicking beds as a greywater or blackwater treatment system.
The "Watson Wick" option that I found on the Oasis webpage (see link provided by Miles) appealed to me as a design option for a non-freezing climate based on the following:
No septic tank requirement
ease of installation and minimal costs if local materials are suitable
Minimal anaerobic conditions
Composting of faecal matter occurs naturally in a sealed environment
Straight forward inspection
design flexibility - The system could be constructed with a liner or no liner depending on site conditions and final effluent could be directed to a wetland or other polishing technology if in a very sensitive area.