From my basic glossing over of what a lagoon septic system is, it's not quite the same as an earthship treatment system. It's very similar though. Where they differ is first in the use of
solar glazing to heat up the sewage, thus increasing the efficacy of the anaerobic bacteria, and also the eventual killing of the pathogens with that high temperature, and second with the recommended usage of plants for the final treatment, which provides a yield that would otherwise not be possible, that is food or beauty in the form of exterior edible or ornamental plant cells. Additionally, the
water can be routed back in once treated for use in again flushing the toilet. This could be especially useful in arid areas, which is where the earthship was developed.
The reason this system is not more widely used is mainly because of its complexity, and also because to the common person, it may sound like it might not be entirely effective. It seems to be largely overlooked in the world of
sustainability, and I'm really not entirely sure why. One of the biggest problems of our time is how to deal with our waste, and it's largely viewed as a big hassle by most municipalities. Similar to all problems viewed with
permaculture goggles on, with prolonged observation and planning, waste management can actually provide many benefits with little actual maintenance or long term effort by those who benefit. This is probably the most effective way of achieving such benefits that I've seen, and perhaps if a concerted marketing campaign were conducted by permaculturists around the world, these sort of systems could become the new norm for home retrofitting and new home building.