A system for handling human wastes and food scraps by composting them without added water, thus producing a safe, rich humus resembling garden soil and a liquid high-nitrogen fertilizer. Among keys to the success of the process are (1) providing properly designed composters which direct air flow over the composting material, (2) using waterless or ultra-low flush toilets, (3) periodic addition of small amounts of high-carbon material such as sawdust to the composter, and (4) separating the wash-water, “greywater,” from baths, lavatories, sinks, dishwashers, and laundries into a separate waste system and subjecting this water to separate treatment, with later use for irrigation. The system is promoted as ecologically sound, offering substantial reduction in water use, resulting in decreased need for public water supplies and sewage systems and sewage treatment plants. The earliest composter reported is the “Clivus Multrum ™”, which has been in use since 1939, and bears the National Sanitation Foundation Seal of Approval. Installations have been successful in private homes and also in such sites as highway washrooms, parks, resorts, schools, community centers, libraries, clinics, and restaurants.