Canteen waste, often overlooked, contributes to greenhouse gas (GHG) emissions through various decomposition processes. Understanding the environmental impact of canteen waste is crucial for sustainable waste management practices. In this blog, we’ll delve into the calculations of GHG emissions from 1 Tonne Per Day (TPD) of canteen waste.
Why Calculate GHG Emissions? GHG emissions are a significant contributor to climate change. By quantifying emissions from canteen waste, we gain insights into its environmental impact, aiding in the development of effective waste management strategies and mitigating climate change.
| Quantity of food waste / day | 1000kg | ||
| Scenario 1: Food waste sent to piggeries | |||
| 1) Food waste from factory premises is transported to piggeries at a distance of 40-60km from factories | |||
| 2) Pigs consume the food waste and grow in size. Unlike cow dung, pigs dung releases very high amount of methane | |||
| 3) Pigs typically consume 2-3 kg of food per day and are slaughtered when they are about 60-80kg in size | |||
| 4) Considering a 1 tonner vehicle transporting waste with average 100 km run per day, it will consume about 10 litres of diesel | |||
| 5) 1 litre of diesel emits 2.68kg of GHG. Per day the waste is transported, it amounts to 26.8 kg of GHG emission per day | |||
| 6) No. of pigs that can be fed with 1000 kg of food waste is approximately 320 pigs | |||
| 7) Amount of GHG emitted per pig in its lifetime is 2.5 – 3.5 metric tonnes of CO2E | |||
| Scenario 1: GHG Emissions per annum | |||
| 1) Transporting of waste | 9,782 | kg of CO2E | |
| 2) GHG Emissions of pigs (60 pigs) | 9,60,000 | kg of CO2E | |
| Total | 9,69,782 | kg of CO2E | |
| Scenario 2: Food waste composted within premises | |||
| 1) Canteen food waste is primarly nitrogen rich material which is mixed with carbon rich material and composted | |||
| 2) Aerobic composting helps in nutrient recovery from the food waste and generates mostly CO2 and water vapour as by products | |||
| 3) 40kg of carbon material is used to treat 200kg 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) | |||
| 4) It is estimated that 1kg of food waste generates 550 of CO2 during composting (60 days) | |||
| Scenario 2: GHG Emissions per annum | |||
| 1) Transporting of carbon material | 536 | kg of CO2E | |
| 2) CO2 emission during aerobic composting | 2,00,750 | kg of CO2E | |
| Total | 2,01,286 | kg of CO2E | |
| Savings in GHG Emissions due to composting | 7,68,496 | kg of CO2E | per annum |
To determine the greenhouse gas savings of composting 1000 kg of food waste versus sending it to a pig farm, we need to consider the emissions associated with each option.
Composting:
When food waste is composted, it undergoes decomposition in an aerobic environment, resulting in the production of carbon dioxide (CO2) and some methane (CH4) during the process. 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.
Sending to a pig farm:
Transporting the 1000 kg of food waste to a pig farm located 60 km away incurs greenhouse gas emissions associated with transportation. The emissions depend on the mode of transportation (e.g., truck, van) and the fuel efficiency of the vehicle used. Additionally, there may be emissions related to pig farm operations, such as the handling of the food waste and the management of pig manure.
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, and the specific practices employed at the pig farm.
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.
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. However, on average, a pig can emit approximately 2.5 to 3.5 metric tons of carbon dioxide equivalents (CO2e) during its entire lifecycle, which includes the emissions from feed production, pig rearing, and manure management. It’s worth noting that these estimates can vary and may depend on regional and production-specific circumstances.
Burning 1 liter of diesel fuel typically releases around 2.68 kilograms of carbon dioxide (CO2) into the atmosphere. However, it’s important to note that the exact amount of greenhouse gas emissions from diesel combustion can vary based on factors such as the engine efficiency and the specific composition of the diesel fuel. 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 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.
Assuming an average feed conversion rate of 3% (pig’s weight to feed ratio), we can estimate the number of pigs that can be fed with 1000 kg of food waste daily.
| Let’s calculate it: |
| Amount of food waste required per pig per day = Pig’s weight * Feed conversion rate |
| Assuming an average pig weight of 100 kg (for simplification): |
| Food waste required per pig per day = 100 kg * 0.03 = 3 kg |
| Number of pigs that can be fed = Total food waste / Food waste required per pig per day |
| Number of pigs that can be fed = 1000 kg / 3 kg ≈ 333 pigs |
| Therefore, approximately 333 pigs can be fed with 1000 kg of food waste every day. Keep in mind that this is an estimate, and the actual number may vary based on the specific circumstances and nutritional needs of the pigs. |
The greenhouse gas emissions from aerobic composting of 1000 kg of food waste can vary depending on several factors, such as the composition of the food waste, the specific composting method used, and the duration of the composting process. However, aerobic composting generally results in lower greenhouse gas emissions compared to anaerobic decomposition in landfills.
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.
While it’s challenging to provide an exact emission value without specific details, on average, aerobic composting of food waste can result in CO2 emissions of approximately 550 grams per kilogram of composted waste. This estimate considers the carbon content of the food waste and the typical carbon-to-CO2 conversion ratio during decomposition.
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.