Waste System Type
Uses wood chips/sawdust, natural decomposition. Minimal water use. End product is safe compost after 12+ months curing.
Install Cost
$3,000 - $8,000
Expected Life
20 years
Hygiene Rating3/5
Pest risk: Low — enclosed system, wood chips deter flies
Environmental: Excellent — produces usable compost, zero water waste
Maintenance: Monthly turning, 6-monthly removal (~$200/yr)
4 people × 0.6 kg/person/day
Biogas Potential
From 2.4 kg/day organic waste (4 people × 0.6 kg/person/day)
Biogas Output
0.4 m³/day
Energy Equivalent
2.2 kWh/day
≈ 1.2 hrs cooking gas equivalent. A small biodigester ($500-2000) can power a gas stovetop for a family.
Composting Output
Daily Input
2.0 L/day
Yearly Compost
292 kg
Enough to fertilise ~58 m² of garden beds. Commercial compost value: ~$146/yr.
Greywater Recovery
Shower, sink, and laundry water recycled for irrigation
AS/NZS 1547 designs on 100. Use 80 for a conservative estimate.
Daily Greywater
380 L
Yearly Volume
138.7 kL
Garden Area
95 m²
At 95 L/person/day, a 4-person household generates 380L of recyclable greywater daily — enough to irrigate ~95 m² of garden. Saves $416/yr on water costs.
10-Year Cost Comparison
| System | Install | 10yr Total | Life |
|---|---|---|---|
| Drop Dunny (Long Drop) | $600 | $1,100 | 10yr |
| Low-Flush Composting | $5,500 | $7,500 | 20yr |
| Standard Septic Tank | $10,000 | $11,250 | 30yr |
| Taylex / Biocycle Treatment | $18,500 | $22,500 | 25yr |
| Worm Farm / Vermifilter (DIY) | $4,000 | $5,000 | 15yr |
| Incineration Toilet | $4,500 | $7,500 | 15yr |
| Biodigester (Anaerobic) | $3,000 | $4,500 | 20yr |
| Dry Vault / Batch Composting | $2,750 | $3,550 | 20yr |