Other waste water can then be easily recycled.  Saving even more water.  All waste water not containing human waste can serve as irrigation water with simple lagoon treatment, covered in hot dry climates to prevent evaporation losses.

Drug compounds would break down in the aerobic digestor as water evaporates into the air.  Oh well.  Another simple solution that goes against the mass delusional corporate culture.

Composting toilets are much less complex and expensive than normal sewer sytems too. 

I saw an ad for a new steam clothes washer that saves water and energy by operating with the energized water molecules of the steam.  it won't be long and someone will come out with clothes and dish washers and shower heads that use compressed air to energize the cleaing action of the water.  Using 10% of normal water for washing.

As with this use of air to substitute for most of the water used in cleaning, aerobic composting substitutes air flow, that feeds break down bacteria and evaporates water, cleaning it with distillation.

The water used to flush and carry waste is conserved.