Life Cycle Assessment of Organic Waste: Application and Relevance to New Zealand Simon Love

PRESENTATION OUTLINE 1. Introduction to LCA 2. LCA and Organic Waste 3. Scion’s ‘Waste 2 Gold’ Project

Part One: Brief introduction to LCA

Introduction to LCA Life Cycle Assessment (LCA) is an analytical tool for the systematic and quantitative evaluation of the environmental impacts of a product or service system through all stages of its life.

ISO STANDARDS ISO – ‘Principles and framework’  Terms used  Phases of an LCA  Methodological framework  Need for critical reviews ISO – ‘Requirements and guidelines’  More detailed guidelines for each step  More specific requirements  Guidelines for critical reviews  Examples of application

Introduction to LCA Life Cycle Assessment Framework Interpretation Impact assessment Inventory analysis Direct applications: Product development and improvement Strategic planning Public policy making Marketing Benchmarking Ecolabels and product declarations Goal and scope definition

Impact Categories in LCA Input-related Categories 1.Abiotic resources (e.g. minerals, fossil fuels) 2.Biotic resources (e.g. fish, logs) 3.Land Output-related categories 4.Global warming 5.Depletion of stratospheric ozone 6.Human toxicological impacts 7.Ecotoxicological impacts 8.Photo-oxidant formation 9.Acidification 10.Eutrophication (incl. BOD and heat) 11.Odour 12.Noise 13.Radiation 14.Casualties Impact categories according to SETAC-EUROPE working group on LCA

Two types of LCA Attributional: -Attributing impact to current activities -i.e. ‘Footprint of process abc’ -Used for comparison and benchmarking Consequential: -Consequences of future activities -i.e. What if we change a to z…? -Higher uncertainty -Decision support

Notables in the Life Cycle Assessment scene Specialist Organisations Crown Research Institutes Legislative and Government bodies UniversitiesConsultants

Part Two: LCA and Organic Waste

Challenges and Opportunities of Organic Waste Challenges: -Large volumes -Methane gas from decomposition -Odour -Leachate -Metals Opportunities: -Energy Source -Conversion to useful products -Carbon-based -N & P - based -Land application -Large volume reduction

New Zealand Waste figures Total waste to landfill, year to June 2010: ~2.5 million tonnes 1 Organic waste at 23%: ~570,000 tonnes

Options for Organic Waste A large proportion of organic waste in New Zealand goes to landfill Other options:  Compost  Anaerobic digestion  Gasification  Pyrolysis  Incineration  Land application (biosolids)

LCA Studies Can quantify important environmental impacts such as:  Global warming (methane production)  Energy (methane for heat/electricity, energy balance of incineration/drying/gasification)  Eutrophication (leachate to rivers/streams) May not be as useful for impacts such as:  Accumulation of heavy metals (land application)  Odour

Can be combined with: Economic (LCC):  Cost of processing  Useful byproducts  Energy production Social factors  Not traditionally in LCA  Emerging field  Necessary to account for human factors!

Part Three: Scion’s ‘Waste to Gold’ Project

Wet Oxidation Technology Feedstock: Biosolids from wastewater treatment High pressure and temperature in oxidising environment Outputs: Useful liquid products or energy, small amount of solids Over 90% solids reduction

Waste to Gold Biomass Deconstruction High Carbon Solid Wastes Energy Recovery Biodegradable Intermediates Bioconversion Liquid biofuels Biopolymers Bioenergy

Economic and Other Potential Benefits Reduction in solid waste to landfill, resulting in increased landfill life Reduction of emissions from solid waste decomposition Can produce a range of useful outputs (organic intermediates or energy)

RDC Case Study Rotorua District Council were interested in wet oxidation of biosolids LCA was employed for environmental comparison of current and future options

Options Compared Current average NZ Landfill Landfill without methane capture Wet Oxidation (‘Waste 2 Gold’) variants Anaerobic Digestion variants Land Application

System Boundary Diagram Infrastructure Buildings

Results W2G showed much promise in:  Global warming potential  Eutrophication potential  Solids Reduction But had high energy and ozone depletion potentials  Sensitivity analysis shows that results are very sensitive to oxygen use and solids content, so much potential for improvement

Other Technologies Anaerobic digestion  Good energy production  Reasonable solids reduction Landfill  Landfill gas capture makes large difference  Still potential for eutrophication and acidification Land application  Low energy alternative  Potential for heavy metals build-up  Application and transport could be a challenge  Public perception

RDC Case Study Pilot scale plant currently being built MfE Waste Management Fund : $1m

Conclusions & Future Work

Conclusions LCA can help to decide on the suitability of future organic waste disposal options in NZ Can provide quantitative and qualitative results in many impact categories LCA assisted in putting case forward to gain WMF Funding for the Rotorua trial

Future Work New Zealand-specific data collection and impact categories Life Cycle Costing and Social LCA Assessment of other new technologies