The International Zero Waste Definition & Hierarchy

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The International Zero Waste Definition

“Zero Waste: The conservation of all resources by means of responsible production, consumption, reuse, and recovery of products, packaging, and materials without burning and with no discharges to land, water, or air that threaten the environment or human health.”

The Zero Waste International Alliance

Last updated

December 20th, 2018

The International Zero Waste Hierarchy

Zero Waste Canada was founded on the principles of Zero Waste as defined by the Zero Waste International Alliance. The Zero Waste Hierarchy 5.0 was adopted by the Zero Waste International Alliance in January 2013 and was revised and adopted by Zero Waste Canada in 2014. Version 6.0 was adopted by both the Zero Waste International Alliance and Zero Waste Canada in December of 2014. It’s most up to date version is featured below.


The Zero Waste Hierarchy describes a progression of policies and strategies to support the Zero Waste system, from highest and best to lowest use of materials. It is designed to be applicable to all audiences, from policy-makers to industry and the individual.  It aims to provide more depth to the internationally recognized 3Rs (Reduce, Reuse, Recycle); to encourage policy, activity and investment at the top of the hierarchy; and to provide a guide for those who wish to develop systems or products that move us closer to Zero Waste. It enhances the Zero Waste definition by providing guidance for planning and a way to evaluate proposed solutions.

Zero Waste Hierarchy of Highest and Best Use 7.1

    • Design and purchase products from reused, recycled or sustainably-harvested renewable, non-toxic materials to be durable, repairable, reusable, fully recyclable or compostable, and easily disassembled
    • Shift funds and financial incentives to support a Circular Economy** over the harvesting and use of virgin natural resources
    • Enact new incentives for cyclical use of materials, and disincentives for wasting
    • Facilitate change in how end users’ needs are met from “ownership” of goods to “shared” goods and provision of services
    • Support and expand systems where product manufacturing considers the full life-cycle of their product in a way that follows the Zero Waste Hierarchy and moves towards more sustainable products and processes. Producers take back their products and packaging in a system that follows the Zero Waste Hierarchy.
    • Identify and phase out materials that cause problems for Closed Loop Systems*
    • Facilitate and implement policies and systems to encourage and support Local Economies*
    • Re-consider purchasing needs and look for alternatives to product ownership
    • Provide information to allow for informed decision-making
  • Be aware of and discourage systems that drive needless consumption
    • Plan consumption and purchase of perishables to minimize discards due to spoilage and nonconsumption
    • Implement Sustainable Purchasing** that supports social and environmental objectives as well as local markets where possible
    • Minimize quantity and toxicity of materials used
    • Minimize ecological footprint required for product, product use, and service provision
    • Choose products that maximize the usable lifespan and opportunities for continuous reuse
    • Choose products that are made from materials that can be easily and continuously recycled
    • Prioritize the use of edible food for people
  • Prioritize the use of edible food for animals
    • Maximize reuse of materials and products
    • Maintain, repair or refurbish to retain Value**, usefulness and function
    • Remanufacture with disassembled parts; dismantle and conserve “spare” parts for repairing and maintaining products still in use
  • Repurpose products for alternative uses
    • Support and expand systems to keep materials in their original product loop and to protect the full usefulness of the materials
    • Maintain diversion systems that allow for the highest and best use of materials, including organics
    • Recycle and use materials for as high a purpose as possible
    • Develop resilient local markets and uses for collected materials wherever possible
    • Provide incentives to create clean flows of compost and recycling feedstock
    • Support and expand composting as close to the generator as possible (prioritizing home or on site or local composting wherever possible)
  • Whenever home/decentralized composting is not possible, consider industrial composting, or if local conditions require/allow, anaerobic digestion
    • Maximize materials recovery from mixed discards and research purposes after extensive source separation
  • If conditions allow, recover energy using only systems that operate at Biological Temperature and Pressure**
    • Examine materials that remain and use this information to refine the systems to rethink, reduce, reuse, and recycle in order to prevent further discards
    • Ensure minimization of impacts by means of biological stabilization of fermentable materials.
    • Encourage the preservation of resources and discourage their Destructive Disposal or dispersal
    • Plan systems and infrastructure to be adjusted as discards are reduced and its composition changes
    • Minimize Gas Production and Release** and maximize gas collection
    • Use existing landfill capacity and maximize its lifespan. Ensure it is Responsibly Managed.**
  • Contain and control toxic residuals for responsible management
    • Don’t support policies and systems that encourage the Destructive Disposal of organics and/or the destruction of recyclables
    • Don’t support energy and Destructive Disposal systems that are dependent upon the continued production of discards
    • Don’t allow the Incineration** of discards
  • Don’t allow toxic residuals into consumer products or building materials

Guiding Questions

7 Rs Guiding Question
Rethink / Redesign What has led us to our present linear use of materials and thus, what needs to evolve to move towards a closed loop model?
How do we re-design systems to avoid needless and/or wasteful consumption?
Reduce What supports the use of less material and less toxic material?
Reuse What supports the better use of those products we already have in ways that retain the value, usefulness and function?
Recycle/Compost How do we ensure materials are put back in the materials cycle?
Material Recovery What was salvaged from mixed waste?
Residuals Management What is still left and why?
What do we need to take out of the system that should not have been circulated in the first place?
How do we manage what is left in a flexible manner that continues to encourage movement towards Zero Waste?
Unacceptable / Regulation What systems and policies encourage wasting and should not occur?

* Guiding Principles

Guiding Principle Definition
Closed Loop Systems Design systems to be closed loop rather than linear in their use of resources.
Close to Source Processes to occur as close to the source as practical.
Conservation of Energy More energy can be saved, and global warming impacts decreased, by reducing waste, reusing products, recycling and composting than can be produced from burning discards or recovering landfill gases.
Do NOT Export Harm Avoid the export of toxic or potentially toxic waste or materials to poorer, less developed areas and avoid the export of materials with limited, undefined recycling markets that will be either landfilled or incinerated in another region.
Engage the Community Promote changes and systems that work with communities to facilitate meaningful and sustained participation, increase understanding, and influence behaviour change and perceptions.
Highest and Best Use Creating and keeping materials and products for a use as high on the hierarchy as possible and in the useful loop as long as possible. Keeping materials from being downcycled where the number of future uses or options are limited. Source separate items and materials to the extent necessary to ensure clean and marketable products and materials for reuse, recycling, and composting streams.
Information & Improvement Collect information on systems and use as feedback for continuous improvement.
Local Economies Support the growth and expansion of local economies (production, repair, and processing) in order to reduce greenhouse gases from transportation, improve accountability, and increase repair and parts opportunities.
Materials are Resources Preserve materials for continued use and use existing materials before harvesting virgin natural resources.
Minimize Discharges Minimize all discharges to land, water or air that may be a threat to planetary, human, animal or plant health, including climate changing gases.
Opportunity Costs Consider opportunity costs of investments and ensure investments occur as high as possible on the Hierarchy.
Precautionary Principle Ensure that a substance or activity which poses a threat to the environment is prevented from adversely affecting the environment, even if there is no conclusive scientific proof linking that particular substance or activity to environmental damage.
Polluter Pays Whoever causes environmental degradation or resource depletion should bear the “full cost” to encourage industries to internalize environmental cost and reflect them in the prices of the products.
Sustainable Systems Develop systems to be adaptable, flexible, scalable, resilient, and appropriate to local ecosystem limits.

** Definitions

Term Definition
Biological Temperature and Pressure The ambient temperature and pressure that occurs naturally without the use of added energy, or in any case not above 100 degrees Celsius or 212 degrees Fahrenheit. Unless higher temperatures are required, not to exceed 150 degrees Celsius, as a pretreatment (e.g. to control diseases or reduce pathogens) to be then subject to composting or anaerobic digestion; the pretreatment should never be used to destroy materials.
Circular Economy An industrial economy that is, by design or intention, restorative and in which material flows are of two types, biological nutrients, designed to re-enter the biosphere safely, and technical nutrients, which are designed to circulate at high quality without entering the biosphere. Materials are consistently reused rather than discharged as waste.
Closed Loop System A system not relying on matter exchange outside of the system, as opposed to open loop where material may flow in and out of the system.
Destructive Disposal Discarded materials placed in a landfill or in an Incineration** facility.
Diversion An activity that removes a material from Destructive Disposal.
Incineration Incineration is a form of Destructive Disposal via combustion or thermal conversion/treatment, using temperatures above 100 degrees Celsius, of discarded materials into ash/slag, syngas, flue gas, fuel, or heat. Incineration includes facilities and processes that may be stationary or mobile, may recover energy from heat or power and may use single or multiple stages. Some forms of incineration may be described as resource recovery, energy recovery trash to steam, waste to energy, energy from waste, fluidized bed, catalytic cracking, biomass, steam electric power plant (burning waste), pyrolysis, thermolysis, gasification, plasma arc, thermal depolymerization or refuse derived fuel.
Minimize Gas Production and Release This means keeping out source-separated organics as much as possible and biologically stabilizing the materials that go into landfill. For existing landfill cells that already contain unstabilized organics, the gas production should be minimized by keeping out rainwater and not recirculating leachate. Minimize methane release by permanently capping closed cells with permanent covers and installing gas collection systems within months of closure (not years). Maintain high suction on collection wells and do not damp down wells or rotate off the wells to stimulate methane production. Filter toxins in the gas into a solid medium that is containerized and stored on site. Note that this is not considered a renewable energy.
Problematic for a Closed Loop System Materials that make it hard to recycle or compost the materials themselves or other materials. These may be contaminants for a material (like some forms of biodegradable plastics or stickers on fruit and vegetables) or materials that clog processing systems (like plastic bags).
Responsibly Managed Landfills Manage landfills to minimize discharges to land, water or air that are a threat to planetary, human, animal or plant health. This must include plans for closure and financial liability.
Sustainable Purchasing The purchase of goods and services that take into account the economic value (price, quality, availability and functionality) and the related environmental and social impacts of those goods and services at local, regional, and global levels.
Value The importance, worth, or usefulness of something that may be economic, social, environmental, or sentimental.

© 2018. Zero Waste International Alliance. Zero Waste Hierarchy of Highest and Best Use 7.1