Food waste recycling

How is food waste recycled?

It is widely acknowledged that food losses and waste (FLW) is a serious global problem and accounts for one-third of the CO2 emissions released each year. According to the Food and Agriculture Organization of the United Nations (FAO), approximately 1.3 billion metric tons of food are estimated to be lost or wasted globally each year. However, efforts to reduce food waste and improve surplus food management will never eliminate all food waste, so food waste recycling plays an important part in reducing greenhouse gas emissions and harnessing an otherwise wasted resource.

What happens to the discarded food, and how is food waste recycled?

What is food loss?

Food loss refers to the decrease in food quantity or quality along the supply chain from harvest or production to the point of reaching the consumer. Food loss can happen due to various factors, including harvesting and post-harvest losses, storage and handling losses, and processing, distribution and transportation losses.

Food loss has significant economic, social, and environmental implications. Economically, it wastes resources, including labour, land, water and energy used for food production. Socially, it contributes to food insecurity and exacerbates issues related to hunger and malnutrition. Environmentally, food loss contributes to greenhouse gas emissions and unnecessary land and water use associated with producing food.

What is food waste?

Food waste refers to the disposal of food that is still safe and edible for human consumption, as well as unavoidable waste, which would include inedible items such as peelings. It occurs primarily at the consumer level, including households, restaurants and food service establishments. Food waste consists of leftover food, expired or spoiled food, discarded food and excessive food preparation that is not consumed. Consumers play a significant role in contributing to food waste. Factors such as purchasing more food than needed, improper storage and preservation, lack of meal planning, and misunderstanding of expiration dates contribute to food waste at the household level.

Food waste also happens at the manufacturing level during the processing, manufacturing, and packaging stages of the food production chain. It includes any food that is discarded, spoiled, or damaged before it reaches the consumer. Several factors can contribute to food loss at the manufacturing level, including quality control issues, equipment malfunctions, processing inefficiencies, excess inventory, overproduction and human error.

Food waste at the retail level refers to the wastage or loss of food that occurs in grocery stores, supermarkets, restaurants, and other food retail establishments. It includes any food that is discarded, unsold, or unfit for consumption at the retail stage. Food waste at the retail level is a significant issue, and several factors contribute to it, including overstocking and poor inventory management, quality and appearance standards, date labelling confusion, damaged or imperfect items, and freshness concerns.

Food waste collection

Food waste collection can vary depending on the specific context, waste management policies, community initiatives and infrastructure available in a particular region. A few standard methods for collecting food waste include curbside collection. Food waste is collected alongside regular municipal solid waste (rubbish) and recyclables. Residents separate their food waste into designated containers and then place it at the roadside for collection by waste management services. In addition, some communities provide designated drop-off locations where individuals can bring their food waste.

Certain institutions, such as schools, businesses, or large-scale food establishments, may have on-site composting systems. They collect food waste generated within their premises and compost it on-site using compost bins or specialised composting equipment. In addition, in urban areas with a high concentration of food-related businesses, commercial services are specifically dedicated to collecting and managing food waste. These services supply specialised bins for food waste collection and transport the waste to appropriate processing facilities for composting or anaerobic digestion.

Food waste recycling methods

Food waste can be recycled through various sustainable treatment methods as an alternative to waste disposal in landfills. In the UK, a food and drink waste hierarchy has been developed, and anaerobic digestion sits at the top of the hierarchy after prevention.

Food waste hierarchy
Food waste hierarchy

Using food waste in livestock and cattle feeds

Using food waste in livestock and cattle feeds can be a beneficial and sustainable practice.

Utilising food waste in animal feed can help reduce the amount of waste sent to landfills, minimising greenhouse gas emissions and preventing the release of harmful substances during decomposition. This practice aligns with the principles of the circular economy, where waste is repurposed to create value.

Food waste can provide a source of valuable nutrients for livestock and cattle. However, ensuring that the food waste used is safe and suitable for animal consumption is crucial. Not all food waste is appropriate for animal feed, as some items may contain toxins, pathogens, or excessive amounts of certain substances that could harm the animals or impact the quality of the resulting products.

Different regions have specific regulations regarding food waste in animal feed. It is essential to comply with these guidelines to ensure the safety and well-being of the animals and prevent any potential negative impacts on food safety.

Food waste destined for animal feed should be appropriately processed and treated to minimise health risks. Methods such as heat treatment, fermentation, or ensiling can help destroy pathogens and improve the nutritional value of the feed. Collaborating with experts or partnering with reputable waste management facilities can help ensure food waste's proper processing and treatment.

Regular testing and quality control measures should be implemented to ensure the safety and nutritional adequacy of the feed. These measures include evaluating the nutrient composition, detecting potential contaminants, and assessing the impact on animal health and performance.

Anaerobic digestion

Anaerobic digestion (AD) is a biological process that occurs in the absence of oxygen, in which microorganisms break down organic matter to produce biogas. The process occurs in an anaerobic digester, a sealed vessel designed to mimic the conditions found in natural anaerobic environments such as a cow’s stomach.

Certain feedstocks, such as food waste, require complex pre-treatment before anaerobic digestion; others, such as agricultural waste and sewage sludge, need simpler pre-treatment processes. You can read more about anaerobic digestion HERE.

The organic matter fed into the digester can come from various sources, including food waste, agricultural waste, sewage, and industrial waste. The microorganisms in the digester break down the organic matter and produce methane, carbon dioxide, and other trace gases, as well as a nutrient-rich liquid called digestate.

The biogas can be used as a renewable energy source, while the digestate can be used as a nutrient-rich fertiliser.

Anaerobic digestion has several benefits, it reduces the volume of organic waste, reduces greenhouse gas emissions, produces renewable energy, and improves nutrient management.

Anaerobic digesters | Anaerobic digestion
Anaerobic digesters | Anaerobic digestion

Insect farming for protein

Insect farming is a growing area of interest as an alternative method to feeding livestock. Black Soldier Fly (BSF) farming is presently the most widespread form of insect farming in the world.

BSF larvae are rich in protein, typically containing 40-60% protein by dry weight. This makes them a valuable source of high-quality protein. Larvae are highly efficient at converting organic waste into protein. They can be fed a wide range of organic materials, such as food waste, agricultural by-products, and manure, turning these waste streams into valuable protein resources. Larvae have a fast growth rate and can reach harvestable size within a few weeks, depending on the species and environmental conditions. This quick turnover allows for high production rates and shorter production cycles.

Larvae can be used as a protein source for animal feed, including aquaculture, poultry, and pigs. They can also be processed into various forms such as meal, oil, or protein powder for human consumption or used to produce pet food and fertiliser. Insect farming can be practised on a small scale using simple setups, such as stacked bins or trays. It can also be scaled up to more significant operations, making it suitable for small-scale farmers and industrial producers.

Insect farming has the potential to reduce the environmental impact associated with traditional livestock farming. It can help alleviate issues related to land use, water consumption, and greenhouse gas emissions.

In-vessel composting

In-vessel composting is a method of composting organic waste materials within a contained environment or vessel. It is a controlled process that takes place in specially designed containers, such as composting bins or reactors. In-vessel composting aims to accelerate the decomposition of organic matter and produce high-quality compost.

Organic waste materials, such as food waste, yard trimmings, or agricultural residues, are typically shredded or chopped into smaller pieces to facilitate composting. The prepared waste materials are then loaded into the in-vessel composting system. These systems are usually equipped with mechanisms for easy loading and unloading of the composting material. In-vessel composting provides a controlled environment for the decomposition process. Factors such as temperature, moisture, and oxygen levels are closely monitored and adjusted as necessary to create optimal conditions for microbial activity and decomposition.

To ensure efficient composting, the materials inside the vessel may be periodically mixed to promote oxygen circulation and facilitate the breakdown of organic matter. Throughout the composting process, various parameters like temperature, moisture content, and oxygen levels are monitored to ensure that the conditions remain within the desired range for effective decomposition. Once the composting process is complete, the resulting material can mature or stabilise to enhance quality. This may involve additional curing outside the vessel to achieve a more finished compost product. The end product of in-vessel composting is a nutrient-rich soil amendment called compost. It can be used in agriculture, landscaping, horticulture, or other applications to enrich soil, improve fertility, and promote plant growth.

In-vessel composting offers several advantages, including faster decomposition rates, reduced odours and pests compared to traditional open-air composting, better control over the composting process, and the ability to handle a wide range of organic waste materials in a compact space. However, it requires specialised equipment and monitoring to maintain proper conditions throughout the process.

In-vessel composting | Agrivert
In-vessel composting | Agrivert

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