Zero Waste Hierarchy of Highest and Best Use 8.0


All over the world, in some form or another, a pollution prevention hierarchy is incorporated into recycling regulations, solid waste management plans, and resource conservation programs that include recovery prior to landfill. Many organizations focused on this 4th R instead of the top of the hierarchy resulting in costly systems designed to destroy materials instead of systems designed to reduce environmental impact and properly manage resources. Because of this, along with other resource destruction systems that have been emerging over the past few decades, the Zero Waste International Alliance adopted the only internationally peer reviewed Zero Waste Hierarchy that focuses on the first 3 Rs Reduce, Reuse and Recycle (including Compost).

Purpose of Hierarchy

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. Users are encouraged to develop policies and actions starting at the top of the hierarchy.

Zero Waste Definition

“Zero Waste: The Conservation of all resources by means of responsible production, consumption, reuse, and recovery of all products, packaging, and materials without burning them and with no discharges to land, water, or air that threaten the environment or human health.”
Version 8.0 — Last updated May 19, 2022

Zero Waste Hierarchy of Highest and Best Use 8.0

Systemic change to move towards a closed loop** model; redesign of systems to avoid needless and/or wasteful consumption. Actions that address the root causes of the current linear use of materials.

1Consider if a purchase is necessary and reject unnecessary, unsolicited items
2Design 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
3Shift funds and financial incentives to support a Circular Economy** over the harvesting and use of virgin natural resources
4Enact new incentives for cyclical use of materials, and disincentives for wasting
5Facilitate change in how end users’ needs are met from “ownership” of goods to “shared” goods and provision of services
6Support 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.
7Identify and phase out materials that cause problems for Closed Loop Systems*
8Facilitate and implement policies and systems to encourage and support Local Economies* 
9Re-consider purchasing needs and look for alternatives to product ownership
10Provide information to allow for informed decision-making  
11Eliminate or avoid systems that drive needless consumption 
** See Definitions below.

Measures taken to reduce the quantity and toxicity of resources, products, packaging and materials as well as the adverse impacts on the environment and human health (while reduction is noted here it is acknowledged that people’s basic needs should be met; not everybody needs to reduce).

12Plan consumption and purchase of perishables to eliminate or avoid discards due to spoilage and non-consumption
13Implement Sustainable Purchasing** that supports social and environmental objectives as well as local markets
14Minimize quantity and toxicity of materials used 
15Minimize ecological footprint required for product, product use, and service provision
16Choose products that maximize the usable lifespan and opportunities for continuous reuse
17Choose products that are made from materials that are easily and continuously recycled
18Prioritize the use of edible food for people
19Prioritize the use of edible food for animals
** See Definitions below.

Actions by which products or components are used again for the same or similar purpose for which they were conceived. Actions that support the continued use of products in ways that retain the value, usefulness and function.

20Maximize reuse of materials and products
21Maintain, repair or refurbish to retain Value**, usefulness and function 
22Remanufacture with disassembled parts; dismantle and conserve “spare” parts for repairing and maintaining products still in use
23Repurpose products for alternative uses
** See Definitions below.

Actions by which discards are mechanically reprocessed into products or materials or biologically processed to return to the soil.

24Support and expand systems to keep materials in their original product loop and to protect the full usefulness of the materials
25Maintain diversion systems that allow for the highest and best use of materials, including organics
26Recycle and use materials for as high a purpose as possible 
27Develop resilient local markets and uses for collected materials wherever possible
28Provide incentives to create clean flows of compost and recycling feedstock
29Support and expand composting as close to the generator as possible (prioritizing home, on site or local composting)
30Consider industrial composting whenever home/decentralized composting is not possible, or if local conditions require/allow anaerobic digestion

Any operation to salvage additional materials after the actions above. Does not include energy recovery and the reprocessing into materials that are to be used as fuels or other means to generate energy, which are unacceptable practices.

31Maximize materials recovery from mixed discards after extensive source separation
32Consider chemical processing in the form of repolymerization (i.e. Plastic-to-Plastic or P2P) only for materials which are not suitable for mechanical recycling
** See Definitions below.

Handling of discards that were wasted in a way that does not threaten the environment or human health. Analyze what was wasted and why.

34Examine materials that remain and use this information to refine the systems to rethink, reduce, reuse, and recycle in order to prevent further discards. 
35Ensure minimization of impacts by means of biological stabilization of fermentable materials. Recover energy using only systems that operate at Biological Temperature and Pressure**
36Encourage the preservation of resources and discourage their dispersal and Destructive Disposal** 
37Plan systems and infrastructure to be adjusted as discards are reduced and its composition changes
38Minimize Gas Production and Release** and maximize gas collection
39Use existing landfill capacity and maximize its lifespan. Ensure it is Responsibly Managed. **
40Contain and control, for responsible management, discards that threaten the environment or human health.
** See Definitions below.

Systems and policies which encourage wasting or threaten the environment and human health.

41Don’t allow policies and systems that encourage the Destructive Disposal and/or the destruction of discards
42Don’t allow energy and Destructive Disposal systems that are dependent upon the continued production of discards
43Don’t allow the Incineration** of discards
44Don’t allow discards to be used in products or materials that risk or cause adverse environmental or human health impacts. 
45Don’t allow chemical processing of discards into fuel** (i.e., Chemical Processing of Plastics to Fuel)
46Don’t allow the use of discards in cement kilns
** See Definitions below.

Guiding Questions

7 RsGuiding Question
Rethink / RedesignWhat 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?
ReduceWhat supports the use of less material and less toxic material?
ReuseWhat supports the better use of those products we already have in ways that retain the value, usefulness and function?
Recycle/CompostHow do we ensure materials are put back in the materials cycle?
Material RecoveryWhat was salvaged from mixed waste?
Residuals ManagementWhat 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 / RegulationWhat systems and policies encourage wasting and should not occur?

Guiding Principles

Guiding Principle Definition
Closed Loop SystemsDesign systems to be closed loop rather than linear in their use of resources 
Close to SourceProcesses to occur as close to the source as practical  
Conservation of EnergyMore 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 HarmAvoid the export of toxic or potentially toxic waste or materials, as well as materials with limited or undefined recycling markets that will be landfilled or incinerated in other regions. 
Engage the CommunityPromote changes and systems that work with communities to facilitate meaningful and sustained participation, increase understanding, and influence behaviour change and perceptions  
Highest and Best UseCreating 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 & ImprovementCollect information on systems and use as feedback for continuous improvement 
Local EconomiesSupport the growth and expansion of local economies (production, repair, and processing) in order to reduce greenhouse gases from transportation, improve accountability and resiliency, and increase repair and parts opportunities 
Materials Are ResourcesPreserve materials for continued use and use existing materials before harvesting virgin natural resources 
Minimize DischargesMinimize all discharges to land, water or air that threaten the environment, or human health, including climate changing gases
Opportunity CostsConsider opportunity costs of investments and ensure investments occur as high as possible on the Hierarchy 
Precautionary PrincipleEnsure 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 PaysWhoever 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 SystemsDevelop systems to be adaptable, flexible, scalable, resilient, and appropriate to local and global ecosystem limits


Biological Temperature and PressureThe 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. (1)
BackfillingAny operation where suitable non-hazardous, non-contaminated inert material such as stone, soil, clay, sand, brick, porcelain, ceramic, or glass is used for purposes of reclamation in excavated areas or for engineering purposes. Discards used for backfilling must be suitable for the aforementioned purposes and be limited to the amount strictly necessary to achieve those purposes. 
Circular EconomyAn 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 wasted. All options that cause leakage or losses of material from their circular management (such as incineration, co-incineration, fuel production, fuel use, and the like) are not part of a Circular Economy system. Circular economy should be clearly defined to follow the Zero Waste Hierarchy and not show energy recovery as a process prior to landfilling. 
Chemical Processing for RecyclingProcessing of carbon-based materials such as plastics repolymerization (Plastic-to-Plastic or P2P). I.e., recovery as new polymers not intended for fuels. This may include solvolysis, solvent-based purification, and the like. Recovery of material for recycling must be over 90%.
Chemical Processing for FuelAny type of process (for example, Plastics to Fuel, P2F) that converts — typically through thermal cracking — most of the carbon included in plastics, into a syngas and/or other fuel. It may also be inappropriately described as “chemical recycling” or “advanced recycling”.
Closed Loop SystemA 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 DisposalDiscarded materials placed in a landfill or in an Incineration** facility
DiscardsMaterials that are disposed of because they are no longer useful or desirable to their current owner. This includes but is not limited to materials sent for reuse, composting, recycling, landfilling, or incineration. 
IncinerationIncineration is a form of Destructive Disposal via combustion or thermal conversion/treatment 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, refuse derived fuel, or chemical processing of plastics to fuel.
Minimize Gas Production and ReleaseKeeping out source-separated organics 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 SystemMaterials 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 LandfillsManage landfills to minimize discharges to land, water or air that threaten the environment and human health. This must include plans for closure and financial liability.
Sustainable PurchasingThe 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. 
ValueThe importance, worth, or usefulness of something that may be economic, social, environmental, cultural, or sentimental. 
(1) Unless higher temperatures are required as a pretreatment, not to exceed 150 degrees Celsius (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.

Version 8.0 — Last updated May 19, 2022

The Zero Waste Hierarchy is originally based on Environmental Hierarchy of Waste Management & Energy Production Methods / Fuels / TechnologiesEnergy Justice Network, Mike Ewall