For separately collected, suitable biodegradable waste, well-managed anaerobic digestion generally offers advantages over landfill: it captures biogas for useful energy and allows nutrients to be recovered through appropriate digestate use. Landfill gas extraction can also recover landfill gas (predominantly methane), but landfill disposes of material out of sight, rather than providing the same controlled treatment and nutrient-recycling route.
Assessing anaerobic digestion vs landfill matters to businesses choosing a waste contractor and to households separating food scraps for collection. The comparison needs to consider the actual waste, the quality of each facility and what happens to its outputs.
Originally published on 20 January 2020. Updated on 20 October 2026 to clarify methane emissions, landfill controls, digestate management and the scope of the comparison.
Anaerobic Digestion vs Landfill for Waste Disposal
The starting point is suitable biodegradable material, such as unavoidable food waste. Anaerobic digestion is not a replacement for landfill for every type of rubbish: glass, metals, plastics and other non-digestible materials require different management routes.
Preventing waste remains preferable to treating it. Where food is still suitable for people to eat, keeping it in the food supply should be considered before energy recovery.
For food that cannot be used, the US Environmental Protection Agency’s Wasted Food Scale places anaerobic digestion with beneficial digestate use above landfilling. That assessment applies to wasted food, rather than every material in municipal waste.
Our comparison considers:
- Control of methane and other emissions.
- Recovery of useful energy.
- Recycling of nutrients.
- Land, storage and infrastructure requirements.
- Operating costs, environmental safeguards and long-term responsibilities.
What Happens to Waste During Anaerobic Digestion
In an AD plant, microorganisms break down biodegradable material without oxygen. The process produces biogas and digestate.
Suitable feedstocks can include food waste, manure, crop residues and sewage sludge, but a particular plant can only accept materials compatible with its design and authorisation. Contamination and feedstock characteristics affect handling and biological performance.
Biogas contains methane, carbon dioxide and smaller quantities of other constituents. After appropriate treatment, it can supply heat or an engine-generator. Alternatively, upgrading can produce biomethane for suitable gas networks or other applications.
Read our guides to anaerobic digestion and the uses of biogas for further explanation.
Digestate retains nutrients and organic matter that have not been converted into gas. Where quality and regulatory requirements are met, it can be used as a fertiliser or soil amendment.
That use requires nutrient planning, suitable storage and appropriate application. Digestion does not automatically remove plastics, metals or all pathogens, and digestate is not automatically compost.
Some digestate carbon may contribute to soil organic carbon, but its persistence varies. Applying digestate does not establish permanent carbon storage or automatically make an AD plant carbon-negative. See our discussion of digestate and soil organic carbon.
What Happens to Waste When Placed in a Landfill
Waste treatment before landfilling varies between countries and facilities. Some systems divert food waste and recyclable materials before disposal; others still landfill substantial biodegradable material.
Modern engineered landfills use measures such as liners, leachate collection, cover systems and environmental monitoring to limit pollution. They should be distinguished from uncontrolled dumping.
Biodegradable material can decompose anaerobically inside a landfill and produce methane-containing landfill gas. Collection systems can recover that gas for energy or controlled flaring.
The EPA’s landfill gas guidance explains how gas wells and collection pipework recover gas from the waste.
However, recovery is not complete. Performance varies with the stage of filling, timing of collection, cover condition and operation. Rapidly decomposing food waste can release methane before effective collection is established.
There is no single capture percentage that accurately describes every landfill throughout its life.
Liquid draining through waste forms leachate. Its collection and treatment help protect water quality. Landfills therefore carry continuing responsibilities for gas, leachate and site management, including after waste acceptance ends.
These are real engineering obligations, but they do not mean every landfill inevitably causes groundwater contamination.
A Comparison of Anaerobic Digestion vs Landfill
The important differences are summarised below.
| Factor | Anaerobic digestion | Landfill |
|---|---|---|
| Suitable material | Specified biodegradable feedstocks. | Waste accepted under the site’s disposal authorisation. |
| Biological process | Managed digestion within a designed treatment system. | Decomposition within the deposited waste mass. |
| Methane management | Gas collection is integral to an energy-producing digester. | Gas recovery depends on collection coverage, timing and operation. |
| Energy recovery | Biogas can supply heat, electricity or upgraded fuel. | Collected landfill gas can supply energy where viable. |
| Nutrients | Suitable digestate can provide a nutrient-recycling route. | Landfilling does not provide a comparable routine fertiliser product. |
| Space | Needs plant, reception, storage, access and output-management capacity. | Consumes finite disposal capacity as waste accumulates. |
| Continuing responsibilities | Plant operation, emissions control and digestate management. | Gas, leachate, containment and aftercare. |
1. Treatment and Resource Recovery versus Disposal
Anaerobic digestion treats suitable organic material and recovers energy and potentially useful nutrients. It converts part of the organic matter into gas rather than retaining the entire incoming material.
Landfill provides a disposal route. Even when gas is recovered, most of the deposited material remains within the site rather than being returned as a controlled nutrient product.
Energy recovery and nutrient recycling should be distinguished: producing biogas recovers energy, while appropriate digestate use recycles nutrients.
2. The Need for Ever More Space for Landfills
A landfill has finite capacity. Continued disposal eventually requires additional authorised capacity or another management route.
An AD plant processes successive loads through its treatment system. It does not need to retain all incoming waste permanently on site.
However, its land requirements extend beyond the digester tank. Feedstock reception, gas equipment, digestate storage, traffic movements and environmental controls require space.
Where digestate is applied to land, adequate agricultural outlets are also needed. Those outlets must be assessed against nutrient demand and application constraints.
3. The Need for Resources to Replace Materials Placed in Landfills
Recovering nutrients from suitable digestate can reduce demand for some manufactured fertilisers. Using recovered biogas can displace other energy supplies.
Landfilling does not offer the same nutrient-recycling opportunity, although it may recover some energy from collected gas.
Neither route is resource-neutral. Collection vehicles, infrastructure, maintenance and processing consume materials and energy. A fair comparison includes these requirements and the quality of the recovered products.
Which Option Has Lower Greenhouse Gas Emissions?
For suitable food waste, well-managed AD can provide a better climate outcome than landfill. The result depends on avoiding methane losses, recovering useful energy and managing digestate responsibly.
The International Energy Agency’s assessment of biogas projects identifies methane control, covered digestate storage and leak detection and repair as important measures.
An AD plant’s environmental impacts are not confined to accidents. Routine methane leakage, ammonia emissions, nutrient losses, transport and energy consumption can also matter.
Likewise, the landfill comparison should account for actual gas collection, oxidation, energy recovery and long-term management. Comparing an ideal digester with an uncontrolled dump would not fairly represent two well-managed facilities.
Costs and Choosing a Waste Contractor
There is no universal cost ranking. Collection arrangements, contamination, transport distance, energy income, treatment charges, taxes and local capacity affect the price.
Businesses should assess more than the quoted gate fee. Ask:
- Is the facility authorised to accept the material?
- How are packaging and contaminants handled?
- What happens to rejected material and process residues?
- How is gas used and how are emissions controlled?
- Where does digestate go?
- What contingency arrangements apply during downtime?
A reputable contractor should explain the complete route rather than simply describe it as “green”.
Anaerobic Digestion vs Landfill – The Verdict
Anaerobic digestion technology is not yet fully developed and far from perfect as a recycling method. It is in general more expensive than the average cost globally of landfilling, especially if landfill taxation is allowed for.
The digestate must be disposed of sustainably and there are limitations on for how long individual fields can be fertilised from digestate in any period of time, before it is necessary to move on. Care is needed to prevent odours, and there are health risks to the operating staff from methane if basic safeguards are not applied.
Nevertheless, in the long-term the anaerobic digestion process has great promise and if developed to its maximum there is no reason why it should not be applied for thousands of years. It needs no energy to fuel it as it is easily capable of providing its own power and much more besides.
Environmental damage from anaerobic digestion is limited to such errors as digester tank leakage, or an explosion of the stored methane. Such damage can be severe at the time and costly.
However, costs for AD plant repair would generally be in the range $100k to $2million. Whereas, the cost of landfill pollution impacts can be much higher. If a landfill pollutes a river or a groundwater aquifer and thereby removes a town or city’s water supply the costs would compound year after year starting at (say) $2million up to $200million or more.
In addition, landfill cannot be sustained for long, and in some of the largest and oldest urban nations it is already not a viable option, for reasons such as land availability. It also requires a lot of non-renewable fuel to develop and fill landfills
Much of the biogas if extracted and used only pays back on the embedded carbon emissions from its construction.
Existing landfills are designed to last for no more than a hundred, perhaps 200 years, nobody rally knows because none have been tested for long enough to know. So, even if satisfactory today, they provide a future threat to the local environment which can be very costly for future generations.
Clean up costs for landfills range from $500k to $billions, as has been the reality already in the United States. For example, the NY, Freshfields Landfill Clean-Up Superfund Mothballing and Capping ($1.2 Billion).
Therefore, on the grounds of sustainability and risk of future environmental damage anaerobic digestion is undoubtably best.
On the grounds of reputation risk to businesses deciding to change their organic (biological) waste disposal from landfill to an AD plant, each will make their own decisions. Individual biogas plants will inevitably fail, but in principal the risk of that is offset by awarding the contract to a well-established and well-run biogas organisation.
Further Reading
- US EPA: Wasted Food Scale
- US EPA: Basic information about landfill gas
- IEA: Key issues affecting biogas and biomethane projects
- Our guide to digestate
