Conventional buildings treat human waste as a disposal problem. A regenerative building treats it as a resource. Greywater from sinks, showers, and laundry is rich in nutrients and, after appropriate biological treatment, is valuable for plant irrigation. Blackwater from toilets contains nitrogen, phosphorus, and potassium in concentrations that, after treatment in a botanical cell system, can support significant plant growth without adding any burden to municipal sewer infrastructure.

The Pangea liquid waste treatment system uses a sequence of botanical cells, designed growing planters filled with specific filter media and planted with productive species, to biologically process and clarify waste water on-site. Interior botanical cells treat greywater; the treated water is pumped to flush toilets. Exterior botanical cells treat the resulting blackwater; the treated effluent supports exterior landscape planting. A conventional septic backup is provided and can be bypassed to, meeting code requirements while maintaining the full botanical treatment system as the primary treatment pathway.

This system closes the water loop in the building. Water enters as rain. It is used for household purposes. The resulting greywater is treated and reused to flush toilets. The resulting blackwater is treated and directed to landscape. Very little leaves the site as waste. Book 6 of this series, Liquid Waste Water Treatment, covers the complete design and construction of this system, including plumbing layouts, plant selection, the gWOM and tWOM control modules, and maintenance procedures.

The Four-Cycle Water System

Rain → Cistern → Potable supply → Household use

Household greywater → Interior botanical cell → Treated greywater → Toilet flushing

Blackwater → Septic tank → Exterior botanical cell → Landscape irrigation

All waste treated on-site. Net water discharge: near zero.