Composition of Juice Varied between trials and over time Low pH – around 4 to 4.5 High COD (soluble) – 83,000 to 160,000mg/L Nitrogen (ammonia) – 2,000mg/L + Phosphorus (organic) – 1,400mg/L & 360mg/L + Potassium – 2,600mg/L + Trends FERM 1 FERM 2
The Fermentation Trial 1 had higher nutrient and COD levels High juice content from predominantly vegetable waste in Trial 2 Differences based on feed material Juice production = waste volume reduction Lactic acid production assumed Liquid fertiliser (after pH adjustment)
Microbial Parameters (Liquid) High numbers of microbes (aerobic/anaerobic) Faecal Coliforms and Escherichia coli present in first sample of Trial 1 only NO BAD GUYS! Below Detection Limits Enterobacteriaceae, Staphylococcus aureus, Clostridium perfringens, Listeria monocytogenes, Salmonella sp.
What Did We Monitor? SOLIDS + COMPOST-ZING LIQUID BURIAL IN GARDEN/MEDIA Analysis Key Nutrients Carbon Composition
Post-Burial Analysis (0 to 8 Weeks) Org Matter: Trial 1: 38.6% to 46.2% Trial 2: 6.1% to 8.5% C Trial 1: 22.4% to 26.8% Trial 2: 3.5% to 4.9% N Trial 1: 1.2% to 1.7% Trial 2: 0.4% to 0.5% P Trial 1: 0.2% to 0.4% Trial 2: 0.2% slight increase K Trial 1: 0.5% to 0.7% Trial 2: 0.2% to 0.3% Trial 1 @ 4 Weeks
Conclusions Common food pathogens absent in juice samples after fermentation No discernable odour High N, P and K content in juice + low pH Solid material breaks down rapidly in soil or compost pile Further targeted testing of COD composition and microbes on commercial systems.
Decentralised Waste Treatment HOUSEHOLDS: COMMERCIAL: ON-SITE USE COMMUNITY GARDENS PARKS/RESERVES AGRICULTURE
Where To From Here? Waiheke Island – Mudbrick Vineyard, Te Whau Brasserie, Lure Vineyard, Café Get Stuffed Hamilton (Back to Earth Programme) Hanmer Springs (Business Association) Waitakere City (Project Circle)
Standards To Be Met Resource Consent Requirements Work with Regional Councils BioGro Certification NZ – NZBPCC Standards