One of the joys of self-sufficiency is dealing with your own shit. After considering all (and I do mean all!) alternatives, we installed a septic-tank system, followed by a reed-bed system for secondary and tertiary treatment of our blackwater.
Invaluable in our research and design were the book "Sewage Solutions: Answering the Call of Nature", the Centre for Alternative Technology's pamphlets "Constructed Wetlands and Reed Beds" and "Making Use of Grey Water in the Garden". I see that these last two are now available from CAT as PDF downloads! If ever you have the chance to visit CAT (in Wales) it is very well worth spending a day. I would love to go there again, since there were many new developments still in the works when J and I visited in about 2000.
Septic-tank systems do have a significant downside, though. A septic tank is, after all is said and done, nothing more than a settling tank. About 4% of what goes into them is insoluble, and cannot be washed out or broken down by bacteria, so after some years of usage the septic tank tends to silt-up. More fastidious waste-system designers recommend pumping the tank out every year - probably simply to avoid running foul of local waste-management regulations. Actual mean-time-between-pumping depends totally on the number of people using the system, size of the septic tank and frequency of toilet flushing.
It has now been about 6 years since last we had our septic tank emptied, and it has reached the point where the inlet tends to easily block, particularly if we have guests staying, as we have had for the past several weeks. Eventually I have the delightful job of opening the tank and prodding the errrr... mass?... with a stick until the inlet unblocks and everything runs normally again for a while.
Ultimately I have to face the fact that we need to get the "sucking Suzie" up here to pump the contents out. The very real problem, though, is that the municipality charge R1200 (at last enquiry, some years ago) for this service, and this is, not to put too fine a point on it, more than we can presently afford.
Of course it is possible to empty the tank "by hand" - using a bucket, but one is still faced with the problem of disposing of the contents whilst keeping the peace with one's neighbours, and avoiding polluting downslope water.
I will have to toss the entire problem into the laps of the municipal bureaucracy. Can't wait!