In order to set up hygienic systems of human waste disposal, to retrieve and re-use the nutrients from human waste, and to economise water use, the concept of eco sanitation has been developed.
A contentious approach to sanitation is eco sanitation where sanitation can be viewed as a three-step process dealing with human excreta, containment, sanitization and recycling. The objective is to protect human health and the environment while reducing the use of water in the sanitation system and recycling nutrients. In practice, eco sanitation includes options such as flush-free (and odour-free) urinals, separation toilets for urine and faeces, dry and composting toilets, dehydration devices for composting of faeces, use of faeces or excreta for the generation of biogas, vacuum sewers and flush systems operating on minimal amounts of water etc.
Any way you can save a bit of water is a good thing.