Table 6.4 Characteristics of different toilet designs
| Toilets | Litres /flush |
Technical features | Benefits/constraints |
|---|---|---|---|
| Conventional flush | 6–15 | Single flush | Low cost; high water use; good range of systems available |
| Dual flush | 0.5–6 | Two flush options | Low cost; medium water use; good range of systems available. |
| Vacuum toilets (discharge to vacuum sewer) | 0.5–1.5 | Separate vacuum unit required | Low water use; expensive; would have to import systems into NZ; limited range (can only be used in conjunction with a vacuum sewerage collection system) |
| Urine-separating (discharge to urine-holding tank) | 0.2–4 | Separate plumbing for urine and for faeces | Enable recovery of nutrients; not common in NZ; requires separate urine-handling system |
| Hybrid or micro-flush (toilet pedestal located on top of pre-treatment tank) | < 0.3 | Very small quantity of water used to flush | Very low water use; available only from Australia; separate greywater system required |
| Composting | 0–0.1 | No water used | Not flushed after use; cleaning instructions are maunfacturer specific; requires on-site management of compost and separate greywater system |
| Dehydrating | 0 | No water used | No water used; requires on-site management of removed solids and separate greywater system |
| Incineration | 0 | No water used | No water used; requires on-site management of removed ash and separate greywater system |
