Canteen waste, often overlooked, adds to greenhouse gas (GHG) emissions whether it’s sent to landfills or used for feeding pigs. It’s important to recognize the environmental impact of canteen waste for better and more sustainable waste management.
Why Calculate GHG Emissions?
GHG emissions play a major role in climate change. Measuring emissions from canteen waste helps us understand its environmental impact and create better waste management strategies to reduce climate change effects.
How does feeding canteen food waste to pigs lead to GHG emissions?
To understand how feeding canteen food waste to pigs results in GHG emissions, we need to consider several factors: the collection and transportation of the waste, feeding it to pigs, and the overall impact on GHG emissions.
Key factors include:
- Distance between the factory and pig farm
- Daily GHG emissions from fuel used in transportation
- Daily food consumption per pig
- Lifetime methane emissions per pig
| Scenario | Data |
|---|---|
| Average distance from factory premises to piggery farm | 40km to 60km |
| Fuel consumption for 1 tonner vehicle transporting waste with average 100 km run per day | 10 liters of diesel |
| GHG emission per liters of diesel | 2.68kg of GHG |
| Daily food consumption per pig | 2kg to 3kg & slaughtered around 60kg-80kg |
| Amount of GHG emitted per pig in its lifetime | 2.5 – 3.5 metric tonnes over a 9-month lifespan |
Considering the above data let us now calculate the GHG emissions contributed per annum due to transport of 1 ton of canteen food waste to piggeries per day. From 1 ton of food waste, over 320 pigs can be fed each day which in its lifetime generates a whopping 960 tons of GHG in 9 months.
| GHG Emissions due to piggeries per annum | Data |
|---|---|
| GHG Emissions due to transporting of canteen food waste | 9.782 ton |
| GHG Emissions of pigs (320 pigs) | 960 metric ton |
| Total | 970 metric ton |
To obtain specific emission values for transportation and pig farm operations, it would be necessary to consider factors such as the type of vehicle used, fuel consumption. This estimate is based on the carbon content of diesel fuel and the standard carbon-to-CO2 conversion ratio. Other greenhouse gases, such as methane and nitrous oxide, may also be emitted during diesel combustion, but their quantities are generally lower compared to CO2 emissions.
The estimate of greenhouse gas (GHG) emissions from pig farming is based on data from,
Academic Research: Journals such as Livestock Science and Agricultural Systems.
Government Reports: Publications from the U.S. Environmental Protection Agency (EPA) and the European Commission.
International Organizations: Reports from the Food and Agriculture Organization (FAO) and the Intergovernmental Panel on Climate Change (IPCC), including FAO’s Livestock’s Long Shadow.
Industry Reports: Documents from organizations like the National Pork Board.
Environmental Impact Studies: Life cycle assessments and studies conducted by environmental consulting firms and universities.
These resources provide a range of methodologies and data, resulting in varying estimates of emissions from feed production, digestion, and manure management
The amount of greenhouse gases emitted by a pig during its lifecycle can vary depending on various factors such as its diet, management practices, and waste management systems. The amount of food waste required to feed a pig can vary depending on factors such as the pig’s size, age, and nutritional requirements. On average, a pig consumes around 2-4% of its body weight in feed per day. It’s worth noting that these estimates can vary and may depend on regional and production-specific circumstances.
What is the GHG emissions impact of disposing of canteen food waste in landfills?
Food / Canteen Waste sent to landfill undergo long term slow decay over a period of 10-12 years. As per the Clean Development Mechanism (CDM) guidelines of calculation of GHG by sending Municipal Solid Waste to landfill, every 1 ton of waste sent to landfill for 1 year (365 tons total), generates 2650 tons of GHG over a 1 year period. Sending food / canteen waste / household kitchen waste to landfills has long term impact to global warming by emission of GHG over extended period of time.
| GHG Emissions due to land disposal of waste per annum | Data |
|---|---|
| Total canteen food waste disposed into landfill per annum considering 1 ton per day | 365 metric ton |
| GHG emissions from disposing of food waste in a landfill for a year | 2650 metric ton |
How much can GHG emissions be reduced through at-source composting?
To calculate the GHG savings from composting canteen food waste on-site, the following factors must be considered:
- Canteen food waste is primarily nitrogen rich material which is mixed with carbon rich material and composted
- Aerobic composting helps in nutrient recovery from the food waste and generates mostly CO2 and water vapour as by products
- 166kg of carbon material is used to treat 1000kg of canteen waste. This carbon material decomposes and provides organic carbon to soil along with nutrients (N, P, K, Ca, Mg, Zn, Cu, Mn etc)
- It is estimated that 1kg of food waste generates 550kg of CO2 during composting (60 days)
| GHG Emissions due to composting per annum | Data |
|---|---|
| Transporting of carbon material | 536kg |
| CO2 emission during aerobic composting | 200.75 metric ton |
| Total | 201.29 metric ton |
| Savings in GHG Emissions due to composting per annum | 768.5 metric ton |
During aerobic composting, microorganisms break down the organic matter in the presence of oxygen, primarily producing carbon dioxide (CO2) as a byproduct. Methane (CH4) emissions, which have a higher global warming potential than CO2, are typically minimal in aerobic composting due to the oxygen-rich conditions that inhibit methanogenic bacteria.
The exact amount of emissions can vary depending on composting methods, conditions, and the composition of the food waste. On average, composting food waste produces lower methane emissions compared to anaerobic decomposition in landfills.
In general, composting food waste is considered a more environmentally friendly option as it can reduce methane emissions from landfills and promote the production of nutrient-rich compost that can be used for soil improvement. However, quantifying the exact greenhouse gas savings would require a detailed analysis considering the specific circumstances and factors involved in both composting and pig farm operations.
It’s important to note that composting has additional environmental benefits beyond greenhouse gas mitigation, such as diverting waste from landfills, reducing odor and leachate production, and producing nutrient-rich compost that can be used to enhance soil health and fertility.
Estimates of greenhouse gas (GHG) emissions from 1 kilogram of food waste during decomposition are derived from:
Scientific Research: Journals like Waste Management and Journal of Environmental Quality.
Government Reports: Agencies such as the U.S. EPA and European Environment Agency (EEA).
International Organizations: FAO and IPCC reports.
Industry Reports: Publications from organizations like WRAP and environmental consulting firms.
Life Cycle Assessments (LCAs): Studies from universities and research institutions.
These sources provide data on methane and carbon dioxide emissions from various decomposition methods.
To learn more about the advantages of composting compared to biogas, please read the following – https://orbin.in/resources/compost-versus-biogas/
Carbon Sequestration potential of compost:
It is to be duly noted that only composting and a process and compost as the end product of the process has the potential to help in carbon sequestration and thereby helping in reversing climate change. The summary of the above claim is as follows:
Compost is carbon rich material and when applied to soil increases beneficial microbes population in the soil. One such beneficial microbe is mycorrhiza which uses CO2 as raw material to produce complex carbon compound called “glomalin”. This carbon compound does not degenerate back into carbon di oxide and there by becomes part of the mass of the soil. Every hectare of land when treated with compost can sequester 2 metric tons of CO2 from the atmosphere annually.
The above is the true potential of aerobic composting of waste and applying the compost generated to soil, which no other waste treatment process can provide.
Reference: Regenerative Organic Agriculture & Climate Change – Rodale Institute (https://rodaleinstitute.org/wp-content/uploads/rodale-white-paper.pdf)
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