Toilet waste collecting system that composts solids using aerobic bacteria.
Treatment Level: Primary
Relative Cost: medium – high
Amount of Maintenance Interaction: medium
Beneficial Byproduct: some – lots (compost)
- Significantly reduces water use, which in turn protects well supply or lowers water bills
- Produces “humus” so that nutrients can be reused safely
- Must use waterless or foam flush toilets to minimize liquids.
- Must have separate plumbing system for graywater.
- Must be located on a basement level (below all toilets, but still accessible).
Operation & Maintenance
- Add bulking agents such as sawdust, straw, shredded newspaper, etc. every 1-3 months.
- Allow compost to age a minimum of 12 months before removing for use.
Blackwater vs Graywater?
- Because aerobic treatment is sensitive to excess moisture, composting toilets are for blackwater only.
Secondary Treatment Options
- No secondary treatment needed.
- Can be self-contained units (individual) or a collection system leading to a central composter
- Can be passive (composts unaided by mechanical means) or actively heated and mixed to decrease composting time
- Must include ventilation fans to keep compost aerated and eliminate odors