Target keyword: food waste pre-processing technologies

Food Waste Pre-Processing Technologies: What the EPA Report Really Says

Food waste pre-processing technologies are increasingly marketed to hotels, restaurants, hospitals, universities, supermarkets and other organisations that generate large quantities of unwanted food.

These machines promise to reduce waste volume, cut collection costs, control odours and make food waste easier to recycle. Some suppliers go further, implying that installing an on-site grinder, pulper, dehydrator or so-called “biodigester” is itself a complete food-waste recycling solution.

That assumption deserves much closer examination.

In September 2021, the United States Environmental Protection Agency published a substantial issue paper titled Emerging Issues in Food Waste Management: Commercial Food Waste Pre-Processing Technologies.

The EPA reviewed five main categories of on-site equipment:

• Food-waste grinders
• Aerobic machines described in the report as “biodigesters”
• Pulpers
• Dehydrators
• Aerobic in-vessel units

The report did not conclude that these technologies were inherently good or bad. Instead, it reached a much more useful finding:

Changing the physical form, weight or volume of food waste does not necessarily mean that the food has been recycled or that its environmental impact has been reduced.

The destination of the output remains crucial.

Key Takeaways

• The EPA report was published by the US Environmental Protection Agency, although it supports the wider federal food-loss and waste reduction programme involving EPA, USDA and FDA.
• The report examines on-site pre-processing rather than full-scale anaerobic digestion or centralised food-waste depackaging.
• The word “biodigester” is used in the report for an aerobic food-waste liquefier, not a conventional anaerobic digester.
• In the UK biogas industry, “biodigester” has also long been used informally as another term for an anaerobic digestion plant.
• Grinders and aerobic liquefiers commonly produce an output that is discharged into the sewer.
• Pulpers and dehydrators reduce the volume or weight requiring transport but do not necessarily recycle the food.
• Pre-processing equipment can reduce storage space, odour and collection frequency in suitable applications.
• Water use, energy demand, sewer loading and the final destination must be included in any environmental assessment.
• The EPA found too little independent evidence to conclude that pre-processing is generally better than transporting untreated, source-separated food directly to its intended recycling facility.
• A machine should be selected according to the complete waste-management pathway—not merely its claimed percentage volume reduction.

Why the EPA Investigated Food Waste Pre-Processing

Large food-waste generators face practical problems that households do not usually encounter.

Food waste is:

• Heavy
• Wet
• Biologically active
• Prone to odour
• Attractive to insects and vermin
• Expensive to store and transport

Restaurants, hotels, hospitals, universities, prisons, supermarkets and commercial kitchens may generate enough food waste to require frequent collections.

Equipment manufacturers have responded with machines that alter food waste before it leaves the premises. Depending on the process, the machine may grind, liquefy, compress, dry or partly decompose the food.

The claimed benefits commonly include:

• Lower waste volume
• Reduced weight
• Fewer collection vehicle movements
• Lower hauling charges
• Improved hygiene
• Reduced odour
• Better food-waste measurement
• Improved access to recycling

However, the EPA recognised that manufacturer claims were often supported by limited independent evidence.

Its report therefore asked two fundamental questions:

1. Do these technologies enable or increase food-waste recycling?
2. Do they reduce the food waste’s overall environmental impact?

The EPA found that neither question could be answered simply by confirming that a machine had been installed.

The US Food-Waste Reduction Goal

The United States established a national goal to reduce food loss and waste by 50% by 2030.

That goal was originally announced by the EPA and US Department of Agriculture in 2015. The Food and Drug Administration later joined the federal collaboration.

In June 2024, the agencies published the National Strategy for Reducing Food Loss and Waste and Recycling Organics. It reinforced the importance of preventing avoidable food waste while expanding composting, anaerobic digestion and other suitable recycling infrastructure.

The 2021 pre-processing report should be read within that wider policy context.

It is not an endorsement of every machine described in it. It is an assessment of whether those machines genuinely help the United States move towards prevention and beneficial recycling.

An Important Warning About the Word “Biodigester”

Before considering the equipment categories, it is necessary to explain a serious terminology problem.

For many years, particularly in the UK and international biogas sectors, the word biodigester has been used informally as another name for an anaerobic digester.

Under that established usage, a biodigester is a sealed biological reactor in which microorganisms break down organic matter without oxygen. The process produces methane-rich biogas and digestate.

Many experienced biogas engineers, operators, development organisations and small-scale digester suppliers still use the word in this way.

More recently, some US equipment suppliers have applied “biodigester” to a completely different type of kitchen and commercial food-waste machine.

These proprietary systems generally:

• Operate aerobically rather than anaerobically
• Add water, microorganisms or enzymes
• Break food down into a liquid or slurry
• Produce no useful methane-rich biogas
• Frequently discharge their output to the sewer

The EPA adopted this newer US commercial terminology in its report.

That does not make the older use incorrect. It means that the same word is now being used for two fundamentally different technologies.

To avoid confusion, this article uses the following descriptions:

• Anaerobic digester: A sealed oxygen-free reactor producing biogas and digestate.
• Aerobic food-waste liquefier: The type of on-site machine called a “biodigester” in the EPA report.

Prospective buyers should never accept the word “biodigester” without asking what the machine actually produces.

If it produces no biogas, it is not an anaerobic digester.

Pre-Processing Is Not the Same as Recycling

This is the EPA report’s most important lesson.

Pre-processing changes the food waste before its next management stage. It may alter its:

• Particle size
• Water content
• Weight
• Volume
• Biological stability
• Pumpability

None of those changes proves that recycling has occurred.

For example:

• A grinder may turn solid food into slurry that is sent into a sewer.
• A pulper may produce a semi-dry material that is later landfilled.
• A dehydrator may make a dry powder that has no approved agricultural outlet.
• An aerobic liquefier may reduce the quantity found in the waste bin while transferring the organic load into wastewater.
• An in-vessel machine may produce an immature material requiring further composting before it can be used.

The same equipment can therefore be part of a beneficial recycling route in one location and a poor disposal route in another.

The correct question is not:

“How much does the machine reduce the waste?”

It is:

“What happens to every solid, liquid and gaseous output after the machine has processed the food?”

The Five Technologies Assessed by the EPA

1. Food-Waste Grinders

Commercial food-waste grinders are larger versions of kitchen waste-disposal units.

They use mechanical cutting or maceration to reduce food into small particles suspended in water. The resulting slurry may be:

• Discharged into a municipal sewer
• Collected in a tank
• Transported by tanker to an anaerobic digestion facility
• Combined with another dewatering or pulping stage

Grinding does not biologically treat the food and does not generate biogas.

The food retains biochemical methane potential after grinding. That energy may be recovered if the slurry is transported directly to a suitable anaerobic digester.

However, when the slurry is discharged into a sewer, its route becomes more complicated.

The sewer and wastewater treatment system must then:

• Convey the additional organic load
• Supply pumping energy where gravity flow is insufficient
• Manage additional suspended solids
• Handle fats, oils and grease
• Treat increased biochemical oxygen demand
• Manage any methane formed during conveyance

Biogas will only be recovered if the receiving wastewater resource recovery facility has anaerobic digestion and if enough of the food’s organic content reaches that stage.

Even then, sending food through kilometres of sewer should not automatically be treated as equivalent to delivering source-separated food directly into an AD plant reception system.

2. Aerobic Food-Waste Liquefiers

The EPA calls these machines “biodigesters”. As explained above, they should not be confused with conventional anaerobic digesters.

The machines typically place food waste in a chamber containing:

• Water
• Air or oxygen
• Microbial additives
• Enzymes
• Mechanical mixing
• Sometimes heat

The aim is to accelerate aerobic decomposition and turn the food into a liquid effluent.

The attraction for the operator is clear. Food appears to disappear from the waste-storage area, potentially reducing bin collections, odour and storage requirements.

But the material has not disappeared.

Much of its organic content has either:

• Been biologically oxidised
• Been discharged in the liquid effluent
• Been released as carbon dioxide
• Become microbial biomass

Where the liquid is sent to sewer, responsibility for treating the remaining organic load is transferred to the wastewater system.

These machines do not normally capture useful biogas. Indeed, aerobic treatment may consume some of the readily biodegradable material that would otherwise have produced methane in a properly controlled anaerobic digester.

That does not mean every aerobic liquefier is without value. Some installations may:

• Improve source separation
• Provide accurate food-waste measurement
• Reduce odour and pest problems
• Reduce solid-waste collections
• Enable capture of the liquid for off-site AD

However, those benefits must be weighed against water consumption, electricity use, aerobic loss of energy potential and the impact of the effluent’s final destination.

3. Food-Waste Pulpers

Pulpers usually combine mechanical size reduction with dewatering.

Food is macerated or mixed and then compressed so that some of its water is separated. The system produces:

• A semi-dry organic pulp
• A liquid stream containing water and dissolved or suspended organic matter

The reduced-weight pulp may be cheaper to transport than untreated food waste.

Depending on its quality, it may be sent to:

• An anaerobic digestion facility
• A composting plant
• Animal-feed processing where legally permitted
• Incineration
• Landfill

The environmental value depends on both outputs.

It would be misleading to count only the reduced transport weight while ignoring the separated liquid. If that liquid enters the sewer with a high organic load, part of the waste-management burden has merely been transferred elsewhere.

Pulping may nevertheless be useful where:

• Transport distances are long
• The receiving AD plant accepts the pulp
• The liquid is recovered or appropriately treated
• The food contains little physical contamination
• The reduction in haulage outweighs the machine’s energy and water requirements

4. Food-Waste Dehydrators

Dehydrators use heat to evaporate water from food waste.

They can produce a dry or semi-dry material with a substantial reduction in weight and volume.

This may allow:

• Less frequent collection
• Reduced odour
• Lower transport weight
• Longer storage
• Potential use as an input to a later recycling process

However, evaporating water requires energy.

The claimed environmental benefit therefore depends on:

• The dehydrator’s electricity or fuel demand
• The carbon intensity of that energy
• The amount of water removed
• The original collection frequency
• The transport distance avoided
• The final use of the dried output

A dry food-derived material is not automatically compost.

It may still be biologically unstable when rewetted. It may require further composting, digestion or controlled disposal.

Buyers should be particularly cautious when suppliers describe the output as:

• Compost
• Biofertiliser
• Soil improver
• Organic fertiliser
• A marketable by-product

Such descriptions should be supported by applicable waste regulations, product standards, laboratory testing and evidence of a genuine outlet.

5. Aerobic In-Vessel Units

Aerobic in-vessel systems mix food waste with air and often with a bulking material such as sawdust or woodchip.

They promote controlled aerobic decomposition and may produce a semi-dry organic material.

Some suppliers refer to the immediate output as compost, but in many cases it is better described as a partially stabilised material requiring further curing.

A complete composting process requires sufficient:

• Aeration
• Moisture control
• Temperature
• Residence time
• Biological maturation
• Contaminant control

Rapid loss of weight does not necessarily mean that mature, stable compost has been produced.

In-vessel systems can be beneficial where the operator has:

• Enough space
• A suitable curing area
• Reliable bulking materials
• Good process control
• A lawful use for the output
• Staff able to manage a biological treatment process

They should not be purchased on the assumption that food enters one end and certified compost automatically leaves the other after a few hours or days.

Comparison of Food Waste Pre-Processing Technologies

Why Disposal to Sewer Is Not Automatically Recycling

One of the EPA report’s strongest conclusions concerns liquid food-waste outputs.

Grinders and aerobic liquefiers commonly send their output into the sewer. Pulpers and dehydrators may also discharge separated water containing dissolved and suspended organic matter.

This practice can make a commercial premises appear to have dramatically reduced its solid waste.

However, the organic load has not necessarily been prevented or beneficially recovered. It has been transferred from the solid-waste system into the wastewater system.

Potential consequences include:

• Higher biochemical oxygen demand
• Higher chemical oxygen demand
• Additional total suspended solids
• Fats, oils and grease
• Pipe blockages
• Hydrogen sulphide formation
• Sewer corrosion
• Additional pumping energy
• Additional aeration energy at the treatment works
• Methane emissions during sewer conveyance
• Increased sludge production
• Higher costs for wastewater customers

The EPA’s current Wasted Food Scale places sending food down the drain among the least-preferred management pathways.

This applies even where the receiving wastewater facility has anaerobic digestion. According to the EPA, the recovered energy may not offset methane emissions from sewer conveyance and the additional energy needed for wastewater treatment.

There can be exceptions. Direct delivery of a clean, concentrated food slurry into the reception system of a wastewater treatment plant with spare anaerobic digestion capacity may produce worthwhile biogas.

But that is very different from releasing diluted food waste into an ordinary commercial drain and assuming it will all reach the digester.

Who Pays When Food Waste Goes Down the Drain?

The EPA also identified a potential transfer of financial responsibility.

A commercial operator that liquefies food and sends it down the drain may avoid:

• Food-waste collection charges
• Landfill or treatment gate fees
• Bin rental
• Storage costs

Unless the sewerage provider applies an appropriate trade-effluent charge, the additional conveyance, maintenance and treatment costs may instead be borne by the wastewater utility and its customers.

This creates a risk that the technology appears financially efficient only because part of its cost has been externalised.

A proper assessment should therefore include:

• Water consumption
• Trade-effluent charges
• Biochemical oxygen demand charges
• Suspended-solids charges
• FOG management
• Sewer maintenance
• Wastewater treatment energy
• Sludge handling

Transport Savings: A Genuine but Conditional Benefit

Reducing weight and volume can provide a real environmental advantage.

If a pulper or dehydrator allows a site to replace several collections with one collection, vehicle mileage and associated emissions may fall.

The significance of that saving depends on:

• The original waste quantity
• The percentage weight reduction
• The original collection frequency
• The type and efficiency of the collection vehicle
• The distance to the treatment facility
• The energy used by the machine
• The quantity of water consumed
• The destination of all outputs

A dehydrator powered by high-carbon electricity and serving a treatment facility only a short distance away may produce little or no net benefit.

The same machine at a remote site with costly daily collections may perform much better.

There is therefore no credible universal statement that on-site pre-processing always reduces greenhouse-gas emissions.

The Importance of Retaining Methane Potential

Food waste contains readily biodegradable carbon that can produce biogas in an anaerobic digester.

Mechanical grinding or pulping may make some material more readily accessible to anaerobic microorganisms, although particle-size reduction does not automatically justify the additional energy required.

Aerobic treatment presents a different issue.

When an aerobic food-waste liquefier consumes readily degradable organic matter, part of the energy content is oxidised rather than converted into methane. Carbon is released mainly as carbon dioxide, and heat may also be produced.

The remaining liquid may still have some biochemical methane potential, but it should not be assumed to contain the same recoverable energy as the untreated food.

The EPA therefore identified a need to compare the methane yields of:

• Untreated food waste delivered directly to AD
• Mechanically ground food waste
• Food waste treated in an aerobic liquefier
• Material sent through a sewer before reaching AD

This remains an important research need.

Depackaging Was Outside the Main Scope of the Report

The EPA report is relevant to food-waste recycling, but it should not be mistaken for a comprehensive study of commercial depackaging equipment.

The report specifically focused on machines used on the premises of consumer-facing businesses and institutions.

It excluded several types of centralised equipment commonly found at:

• Anaerobic digestion plants
• Commercial composting facilities
• Food-processing factories
• Waste-transfer stations
• Specialist packaged-food recycling plants

Industrial depackagers perform a different primary function. They separate food from:

• Plastic film
• Rigid plastic containers
• Metal cans
• Cardboard
• Cartons
• Glass
• Composite packaging

Nevertheless, the EPA report’s core principle still applies.

A depackaging machine should be judged according to the complete fate of both its organic output and its packaging reject.

Plastic Fragmentation and Microplastics

The 2021 pre-processing report did not fully evaluate the microplastic risks created by aggressive size reduction.

This is particularly important for equipment that processes packaged food.

Grinding or milling food while packaging remains present can:

• Fragment plastic film
• Break brittle trays
• Detach labels
• Produce small fibres and flakes
• Allow particles to pass through screens
• Contaminate pulp sent to AD or composting

A reduction in visible waste volume is not an environmental success if easily captured packaging has been converted into particles that are harder to separate.

For packaged food, the preferred engineering principle should be:

Open the package, release the food and retain the packaging in the largest practicable pieces.

This improves the prospects for:

• Clean organic recovery
• Packaging recycling
• Metal recovery
• RDF or SRF production where appropriate
• Reduced plastic contamination of digestate

Can the Dry Output Be Called Compost?

Some suppliers use the term “compost” for material leaving a dehydrator or rapid aerobic machine.

That description may be misleading.

Dehydration primarily removes water. It does not necessarily provide the biological stabilisation and maturation associated with composting.

Similarly, a short period of aerobic processing may initiate decomposition without completing the process.

A genuine compost product normally needs to demonstrate appropriate:

• Stability
• Maturity
• Hygienisation
• Contaminant quality
• Plant response
• Nutrient characteristics
• Compliance with applicable standards

Dried or partially digested food may become odorous and biologically active again when water is added.

The output should therefore be described according to what it actually is—not according to the most attractive marketing term.

Food-Waste Data May Be More Valuable Than the Machine

Some pre-processing systems incorporate:

• Weighing equipment
• Digital scales
• Food-type recognition
• Kitchen monitoring
• Waste reports
• Departmental comparisons

These tools can help a hotel, hospital or commercial kitchen identify:

• Overproduction
• Excessive portion sizes
• Preparation losses
• Menu items commonly left uneaten
• Stock-control failures
• Particular times or departments generating waste

That information may support food-waste prevention, which ranks above recycling.

However, a business does not necessarily need to purchase a liquefier or dehydrator to obtain such data. Stand-alone weighing and food-waste monitoring systems are available.

Buyers should therefore separate the value of the measurement software from the value of the waste-processing machinery.

Questions Buyers Should Ask Before Purchasing

1. What Exactly Does the Machine Do?

Ask whether the process is mechanical, aerobic, anaerobic, thermal or a combination.

2. Does It Produce Biogas?

If the answer is no, it is not an anaerobic digester, regardless of whether the supplier calls it a biodigester.

3. Where Does Every Output Go?

Identify the destination of:

• Solid material
• Liquid effluent
• Separated water
• Packaging
• Air emissions
• Cleaning water

4. Is Sewer Discharge Lawful?

Obtain approval from the sewerage authority and establish applicable trade-effluent limits and charges.

5. How Much Water Does It Use?

Water consumption should be measured per tonne of food waste processed.

6. How Much Energy Does It Use?

Request independently verified electricity and heat consumption under representative operating conditions.

7. Is the Output Genuinely Recycled?

Ask for evidence of a continuing contractual outlet rather than a theoretical possible use.

8. What Happens During a Breakdown?

The business still needs adequate storage and collection arrangements when the machine is unavailable.

9. What Cleaning and Maintenance Are Required?

Include labour, chemicals, replacement components and downtime.

10. Are Performance Claims Independently Verified?

Supplier case studies are useful, but they are not equivalent to independent life-cycle or operational testing.

A Better Decision-Making Framework

Businesses should compare at least three complete options:

1. No on-site pre-processing: Store source-separated food and send it directly to an AD or composting facility.
2. On-site pre-processing with off-site recycling: Reduce weight or volume and transport the output to a verified facility.
3. On-site processing with sewer discharge: Liquefy the food and transfer it into the wastewater system, where legally permitted.

The comparison should include:

• Capital cost
• Maintenance
• Electricity
• Water
• Labour
• Consumables
• Waste collections
• Trade-effluent charges
• Treatment gate fees
• Transport distance
• Greenhouse-gas emissions
• Biogas recovery
• Nutrient recovery
• Reliability
• Legal compliance

A machine offering a 90% reduction in bin weight may appear impressive. But the figure has little meaning if most of the missing weight has been discharged as polluted water.

Research Gaps Identified by the EPA

The EPA concluded that substantially more independent work was needed.

Its priority research topics included:

• Full life-cycle assessments
• Independently verified operating data
• Energy and water consumption
• Effects on generators’ recycling decisions
• Impacts on sewer networks
• Impacts on wastewater treatment plants
• Fugitive methane from sewer conveyance
• Comparative biogas potential
• The fate of nutrients and organic matter
• Environmental consequences of different output destinations

The report found that much of the available information came from:

• Equipment manufacturers
• Trade publications
• Supplier case studies
• Interviews
• Non-peer-reviewed reports

That did not make the information worthless, but it limited the strength of conclusions that policymakers or buyers could safely draw.

What Has Changed Since 2021?

The EPA report remains relevant because the basic engineering and environmental questions have not disappeared.

Since its publication:

• The United States has retained its goal of halving food loss and waste by 2030.
• EPA, USDA and FDA published a national food-loss, waste and organics strategy in 2024.
• The EPA replaced its older Food Recovery Hierarchy with the more detailed Wasted Food Scale.
• The current scale ranks prevention, donation and upcycling above recycling.
• Sending food down the drain remains among the least-preferred pathways.
• Anaerobic digestion remains recognised as a valuable route when food is delivered appropriately and biogas and nutrients are recovered.

The direction of policy therefore reinforces rather than weakens the report’s central message.

Prevention comes first. Where food is genuinely unavoidable, the complete recycling pathway matters more than the presence of an impressive machine in the kitchen or waste room.

Conclusion

The EPA’s 2021 report on commercial food waste pre-processing technologies remains a valuable and unusually cautious examination of grinders, pulpers, dehydrators, aerobic food waste liquefiers and small in-vessel systems. Its importance lies not in recommending one particular machine, but in exposing the weakness of judging equipment solely by the reduction in the volume or weight of waste left in a commercial bin.

A machine may reduce collection frequency without preventing food waste. It may lower a business’s solid waste charges while transferring additional treatment costs to the sewerage system. A dehydrator may produce a dry material without creating mature compost, while an aerobic liquefier may make food appear to disappear without producing any useful biogas. Similarly, pre-processed food may still be sent to landfill or incineration if no reliable recycling outlet has been secured.

The use of the word “biodigester” creates an additional and important source of confusion. In established UK and international biogas terminology, the term has long been used for an anaerobic digester that converts organic matter into methane-rich biogas and digestate. In the EPA report and in newer US commercial usage, however, it describes an aerobic machine that generally produces a liquid effluent and no biogas. Buyers should therefore look beyond the name and establish precisely which biological process is taking place, what outputs are produced and where those outputs will go.

The environmental performance of any food waste pre-processing system can only be understood by following the material through its complete management pathway. This means accounting for water and electricity consumption, transport movements, sewer loading, gaseous emissions, the loss or recovery of methane potential, nutrient recycling and the final destination of every liquid and solid output.

In some circumstances, on-site pre-processing can provide genuine benefits. It may improve hygiene, reduce odour, enable better food waste measurement, lower transport requirements or make a previously impractical recycling service viable. Those advantages are real, but they are site-specific and should be demonstrated through credible operating data rather than assumed from a supplier’s headline volume-reduction figure.

The best outcome will usually be achieved by preventing avoidable food waste first and then sending unavoidable, source-separated material through the shortest practicable route to a properly managed anaerobic digestion or composting facility. Where packaged food is involved, effective depackaging should recover clean organic material without unnecessarily fragmenting plastic and contaminating the subsequent digestate or compost.

Reducing the amount of material visible inside a waste container may be operationally convenient, but it does not make the environmental burden disappear. A food waste pre-processing machine should only be considered successful when it supports genuine prevention, recovery or recycling without simply transferring pollution and cost from one waste-management system to another.

Frequently Asked Questions

What is food waste pre-processing?

Food waste pre-processing changes the physical or biological condition of food before its final treatment. It can include grinding, pulping, dewatering, drying or partial aerobic decomposition.

Is food waste pre-processing the same as recycling?

No. Pre-processing is an intermediate stage. Recycling only occurs when the resulting material is beneficially processed, such as through anaerobic digestion, composting or another legitimate recovery route.

What does the EPA mean by a food-waste biodigester?

In the 2021 report, the EPA uses “biodigester” for an aerobic machine that uses water, microbes or enzymes to liquefy food waste. It normally produces no biogas.

Can biodigester also mean an anaerobic digester?

Yes. In the UK and international biogas sector, biodigester has long been used as another name for an anaerobic digester. The context and process description must therefore be checked.

Do commercial aerobic biodigesters produce biogas?

Generally, no. The aerobic liquefiers considered in the EPA report use oxygen and normally discharge liquid effluent. A true anaerobic digester operates without oxygen and produces methane-rich biogas.

Do food-waste grinders produce biogas?

No. A grinder only reduces particle size. The ground food may later produce biogas if it is delivered to an anaerobic digester.

Is sending ground food waste down the sewer environmentally beneficial?

Not necessarily. It can increase organic loading, energy demand, blockages, corrosion and methane emissions in the wastewater system. The environmental result depends on the sewer network and receiving treatment works.

Does a food-waste dehydrator produce compost?

Not automatically. It principally removes water. The output may still require biological treatment, curing, testing and regulatory approval before it can be described or used as compost.

What is the main benefit of a pulper?

A pulper can reduce the weight and volume requiring transport. Its net benefit depends on the destination of the pulp and the management of the separated wastewater.

Which route is best for unavoidable food waste?

Where suitable infrastructure exists, separately collected food delivered directly to a well-managed anaerobic digestion or composting facility will often provide a clearer recycling route than liquefying it into a sewer. Local conditions and full life-cycle impacts should still be assessed.

Sources

1. US EPA: Emerging Issues in Food Waste Management—Commercial Food Waste Pre-Processing Technologies.
2. US EPA Science Inventory record for the commercial pre-processing technologies report.
3. US EPA Wasted Food Scale.
4. US EPA: United States 2030 Food Loss and Waste Reduction Goal.
5. US National Strategy for Reducing Food Loss and Waste and Recycling Organics.
6. US EPA: Anaerobic Digestion.
7. US EPA Food Waste Research.
8. US EPA: Emerging Issues in Food Waste Management—Plastic Contamination.

[Published April 2024. Updated June 2026.]