Effective Solid Waste Treatment in Food Processing

Solid waste management is one of the most pressing challenges in the food processing industry. From peels and pulp to packaging materials, food manufacturing generates enormous volumes of waste that must be handled responsibly. Proper treatment of these wastes not only protects the environment but can also transform what was once a disposal problem into valuable resources for agriculture and manufacturing.

Why solid waste segregation matters 🔗

The first step in effective solid waste treatment is segregation-separating waste into biodegradable and non-biodegradable categories. This simple practice determines how each waste stream can be processed most efficiently. Solid waste from food processing includes items removed from fruits and vegetables such as leaves, peels, pomace, skins, rinds, cores, pits, pulp, stems, and seeds, along with spoiled produce, slaughterhouse waste, and brewer’s grain. Non-biodegradable waste consists primarily of packaging materials like metals, plastics, and glass containers.

Without proper segregation, recyclable materials become contaminated and biodegradable waste ends up in landfills where it creates environmental problems. Taking the time to sort waste streams at the source makes all subsequent treatment processes more effective and economical.

Composting: transforming biodegradable waste into soil gold 🔗

Biodegradable waste from food processing-including fruit and vegetable trimmings, dairy products, grains, and meat by-products-can be composted to create high-quality soil amendments. According to the EPA, composting is the managed, aerobic biological decomposition of organic materials by microorganisms, producing a valuable, biologically-stable soil amendment called compost.

The composting process offers multiple environmental benefits. The EPA notes that compost can be used to build soil health, increase soil water retention, and reduce soil erosion. Perhaps most importantly, EPA research confirms that diverting food waste from landfills is an effective way to reduce methane emissions from municipal solid waste landfills.

The methane problem with landfilled food waste 🔗

When organic waste ends up in landfills instead of composting facilities, it creates significant environmental harm. Municipal solid waste landfills are the third-largest source of human-related methane emissions in the United States, accounting for approximately 14.4 percent of these emissions in 2022. Food waste is a major contributor to this problem.

The EPA estimates that food makes up about 24 percent of material in municipal solid waste landfills, and wasted food is responsible for 58 percent of landfill methane emissions to the atmosphere. Because food waste decays relatively quickly-about half of its carbon degrades to landfill gas within 3.6 years-most of the methane it produces escapes before gas collection systems can capture it. Composting eliminates this problem entirely by maintaining aerobic conditions that prevent methane formation.

The critical role of bulking agents 🔗

Successful composting of food waste requires more than simply piling up organic materials. Bulking agents are essential carbon-based materials that add structure to compost piles. Classic examples include wood chips, wood shavings, sawdust, dry leaves, shredded landscape waste, shredded paper, shredded cardboard, and animal bedding.

Food waste alone presents challenges for composting due to its high moisture content and high nitrogen levels. Without bulking agents, food waste turns into a wet, anaerobic mass that produces foul odours and attracts pests. A typical recipe for hot aerobic composting is two parts bulking agent to one part high-nitrogen feedstocks by volume.

Bulking agents serve multiple functions in the composting process. They create air pockets that allow oxygen to reach microorganisms throughout the pile. They absorb excess moisture from wet food waste. They provide carbon to balance the high nitrogen content of food scraps. And they act as biofilters, with microbes living on the bulking material literally consuming odour compounds from the air.

Maintaining aerobic conditions 🔗

Aerobic composting is recognized as an easy, efficient, cost-effective, and eco-friendly method for managing food waste. The key distinction between aerobic and anaerobic decomposition is oxygen availability. Aerobic decomposition-which occurs in properly managed compost-produces an earthy smell similar to forest soil. Anaerobic decomposition, which happens in landfills and poorly managed compost piles, produces sour, acidic, and putrid odours along with methane.

Maintaining aerobic conditions requires attention to moisture levels, pile structure, and occasional turning. Research shows that composting proceeds most efficiently when the carbon-to-nitrogen ratio is between 30 and 40, and moisture content stays between 50 and 65 percent. Bulking agents help maintain these optimal conditions by absorbing excess moisture while providing the structure needed for air circulation.

Recycling non-biodegradable waste 🔗

Non-biodegradable waste from food processing-primarily metals, plastics, and glass from packaging-requires a different treatment approach. These materials should be sorted and recycled through established channels rather than sent to landfills.

Metals and glass: the recycling success stories 🔗

Metal and glass are considered permanent materials because they do not change their properties during recycling. They can be recycled repeatedly, and the recycled materials are as safe as virgin materials for use in new food packaging. In the EU, metallic packaging achieved a recycling rate of around 76.9 percent, while paper and cardboard packaging reached 83.2 percent.

According to the US EPA, the recycling rate for glass containers was 31.3 percent in 2018. While glass recycling requires significant energy, the material is ideal for reuse because it can be easily cleaned and sanitized. Food processors can contribute to higher recycling rates by establishing clear collection systems and working with waste haulers who prioritize material recovery.

The plastic challenge 🔗

Plastic recycling presents greater challenges than metal or glass. The average recycling rate of plastic packaging in the EU was around 40 percent in 2022, significantly lower than other packaging materials. In the United States, the recycling rate for plastic containers and packaging was only 13.6 percent in 2018.

The complexity of plastic recycling stems from the variety of plastic types and the specialized processes required for their recovery. Most plastic food packaging that is not made of PET cannot be recycled into new food packaging due to missing processes and safety concerns. Food processors should work to minimize plastic use where possible, prioritize recyclable plastic types, and ensure proper sorting to maximize recycling potential.

Best practices for food processing facilities 🔗

Implementing effective solid waste treatment requires systematic approaches at every stage of operations. Start by conducting waste audits to understand the types and volumes of waste your facility generates. Establish clear segregation systems with properly labeled bins for biodegradable and non-biodegradable materials. Train staff on proper waste sorting procedures.

For biodegradable waste, consider on-site composting if space permits, or establish relationships with local composting facilities or anaerobic digestion plants. The EPA notes that anaerobic digestion generates biogas, which can be a source of renewable energy, and produces digestate or biosolids that can be used as fertilizer or soil amendment.

For non-biodegradable waste, work with recycling services that can handle food-contaminated packaging materials. Consider packaging redesign to reduce waste generation at the source. Where possible, choose packaging materials with higher recycling rates and clearer recycling pathways.

Environmental and economic benefits 🔗

Proper solid waste treatment delivers benefits beyond regulatory compliance. Composting transforms a waste disposal cost into a valuable product that improves soil health and reduces the need for synthetic fertilizers. Recycling conserves natural resources and reduces the energy needed to manufacture new materials. Both approaches reduce greenhouse gas emissions compared to landfilling.

The EPA’s Wasted Food Scale emphasizes that the most preferred pathways-preventing waste, donating food, and upcycling-offer the greatest environmental benefits. When waste is unavoidable, composting and anaerobic digestion rank as preferable options that recover value from organic materials while avoiding the methane emissions associated with landfilling.

What do you think? How might your facility improve its waste segregation practices to increase composting and recycling rates? What barriers have you encountered when trying to implement better solid waste treatment systems?

References

1. https://shapiroe.com/blog/waste-management-in-food-processing-industry/
2. https://www.epa.gov/sustainable-management-food/wasted-food-scale
3. https://www.epa.gov/land-research/quantifying-methane-emissions-landfilled-food-waste
4. https://www.epa.gov/lmop/basic-information-about-landfill-gas
5. https://compostingtechnology.com/its-all-about-the-bulking-agent/
6. https://compostingtechnology.com/bulking-agents/
7. https://www.nature.com/articles/s41598-025-85433-0
8. https://www.sciencedirect.com/science/article/abs/pii/S0960852410003159
9. https://foodpackagingforum.org/resources/food-packaging-materials-and-recycling
10. https://www.frontiersin.org/journals/food-science-and-technology/articles/10.3389/frfst.2025.1520532/full
11. https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/containers-and-packaging-product-specific
12. https://www.epa.gov/sustainable-management-food/industrial-uses-wasted-food