Ashki Shkur & Candyce Wong
Age 16 | Vancouver, British Columbia
Natural gas poses a threat to the environment because its high methane levels contribute to global climate change. Therefore, developing alternatives to natural gas is an urgent need. If food waste and cow manure are combined, then the mixture will create an eco-friendly alternative to natural gas. Using biogas is an alternative and easy way to reduce methane gas rather than using natural gas. The lack of adequate research on alternative fuels was the motivation to produce further research on this topic. By mixing various food scraps with cow manure and leaving the mixture in a warm environment for three days, enough biogas was produced to ignite a small stovetop. After three days, the pressure gauge measured a total of 0.708 m3 of biogas. After burning the same amount of natural gas and biogas, it was observed that the biogas burned ten minutes longer. In conclusion, the results show that biogas can be created from food scraps and cow manure and is more efficient than natural gas. Biogas contains less methane than natural gas, reduces soil and water pollution, and uses simple and low-cost technology that encourages a circular economy.
INTRODUCTION
Can biogas be produced out of food waste and cow manure when combined? It was hypothesized that if food waste and cow manure are combined to create biogas, then it will produce an eco-friendly alternative to natural gas.
Methane gas can be harmful to the environment. Using methane gas can be dangerous because if it leaks without burning first it can produce greenhouse gases, which contribute to climate change (Johnson, 2014). Leaked methane gas may absorb heat from the sun and warm up the atmosphere. Biogas is a renewable and clean source of energy that can cut reliance on the use of fossil fuels like coal and oil. Biogas is an attractive alternative to natural gas because it contains about 50-70 percent less methane than natural gas (Clarke and DeBruyn, 2012).
Purpose: This innovation came life due to the interest of producing biogas made from food scraps and cow manure since it is safer for the environment and the human population. This innovation can decrease the high pollution rate experienced in cities around the world. Using biogas instead of natural gas is a good start to decreasing the harmful effects of climate change.
Goal: This innovation was created in the hopes to create a difference in the world by introducing people to biogas made from various food waste and cow manure. Biogas is a safer alternative to natural gas because when methane is released into the air before getting burned, it can be harmful to the environment and the human population. Because methane can trap heat in the atmosphere, it contributes to climate change. Even though creating biogas made from food scraps and cow manure is a small change it can help by preventing more pollution. This project hopes to develop and promote the use of biogas over natural gas in the future.
THE EXPERIMENT
To create the mixture of food scraps, the following were combined: one banana peel, one rotten potato, old bread scraps, rotten grapes, onion peels, mandarin orange peels, used tea leaves, and one liter of water. To create the prototype, the following materials were needed: a knife, a cutting board, mixing bowls, a blender, measuring spoons, two mini stove tops, a pressure gauge, clear rubber hose, gas hose, a tire, screws, a one gallon water jug, and switches.
The independent variables in this experiment were time and materials (cow manure and food waste), while the dependent variable was the amount of gas being produced and its efficiency. To create a controlled system, the type and amount of cow manure and food waste, the environment, and the testing schedule remained consistent.
PROCEDURE
Start by chopping all the food waste into 4 cm sized cubes, then blended all the food waste and put it in a large bowl. Then add half a cup of water to the mixture to make a paste and leave the mixture for two days. After two days put the cow manure in a 5-gallon water jug with two liters of water. After that add all the food waste to the cow manure.
A transparent rubber hose was connected to the five gallon jug, with a switch that connected to two other hoses: a black (gas) hose leading to the stove, and another transparent hose leading to the tire. Switch 1 in figure 1 transferred the gas that is produced in the jug directly to the tire when the switch on the gas hose (switch 3) was turned off and switch 2 was turned on. When the tire was full, switch 1 was turned off, switch 2 was kept on, and switched 3 was turned on so that the gas from the tire would go directly to the stove, igniting the flame.
Figure 1: The biogas created produced a flame on the stovetop.
Figure 2: Candyce and Ashki working on the prototype.
RESULTS
The gas was tested by lighting up a stove top in a room temperature room. The tire collected a total of 0. 708 m3 of biogas in three days. After turning on the stove top, the gas burned for a total of 40 minutes. Over the three days the amount of gas being produced increased. On the first day, only 0.160 m3 of gas was produced, on the second day 0.215 m3 of gas was produced. When the tire was checked on the last day a huge difference was seen: 0.333 m3 of gas was produced. Overall, it was discovered that using cow manure and food waste can produce a very efficient gas, called biogas, which contains less methane than natural gas.
Figure 3: A visual representation of the comparison of the burning time between Biogas and Natural gas
Figure 4: A visual representation of the amount of gas collected in 3 days
DISCUSSION
The data collected from this experiment supported the hypothesis: combining food waste and cow manure will produce an eco-friendly alternative for natural gas. This is true because after turning on the stove top, it lit up and burned for 40 minutes. However, when there was 0.708 m3 of natural gas it only burned for about 30 minutes, which is ten minutes less than the amount of time the biogas burnt for.
A possible error that may have occurred in this experiment is the room temperature the prototype was left in. Some days the environment was a bit warmer than others, which might have been reason why the first two days very little gas was produced compared to the last day of the experiment.
The final possible error is that dried cow manure was used instead of fresh manure which might have been why there was not a lot gas produced since fresh cow manure has a higher chance of producing more gas because it still contains carbon dioxide. However dried manure does not contain as much carbon dioxide which could affect its efficiency.
If this project were to be repeated there a several factors that might have been modified or added in order to produce the most efficient type of biogas. First, replacing the dried manure with fresh manure because it has a better chance of creating more biogas in an even shorter amount of time due to the amount of carbon dioxide and nitrous oxide it still contains. Secondly, for future experiments or researches it would be worthy to compare different proportions of cow manure and food waste to see if it would affect the efficiency of the gas. For example, having more food waste than cow manure or more cow manure than food waste to see whether it would affect gas production. Future researchers can also experiment to discover which methods and locations are best for biogas storage. Lastly experimenting with different types of manure like goats, sheep or any other types of manure to explore which type produces biogas most effectively.
This result shows the potential to create a machine that is connected to an existing house stove for people who live in rural villages. Since livestock such as cows, goats and sheep are common in these locations, it would be advantageous to use animal manure and food waste to produce zero waste biogas for daily use. The machine could double as a trash bin for food scraps and manure and provide low cost energy produced in individual’s homes. This idea would best work for the rural as opposed to urban areas because of the minimal access to animal manure.
Figure 5: Potential extension of the experiment results
CONCLUSION
The results of this project showed that biogas made from cow manure and food waste is extremely efficient and affordable. When burned on a stovetop, the biogas burned ten minutes longer than the same amount of natural gas. Research shows that biogas contains about 50-70 percent less methane than natural gas, which makes biogas more environmentally friendly (environmental and energy study institute 2017). Natural gas is less environmentally friendly because it contains 87% percent of methane gas, which traps heat in the atmosphere, contributing to climate change. This experiment explored the following question: Can biogas be produced out of food waste and cow manure when combined? It was hypothesized that if food waste and cow manure are combined, they will produce an eco-friendly alternative for natural gas. The results proved this hypothesis. In conclusion, the results showed that food waste and cow manure can create biogas, an eco-friendly alternative to natural gas.
ACKNOWLEDGEMENTS
There are many people who helped to make this project become a reality. We would like to thank Ms. Hannah Sugar, Viviana Shiffman, Professor Ries and Professor Lau, for providing us with lots of guidance and support during the experiment. We would also like to thank Jaclyn Morrison and Jessie Murphy for providing writing support. Lastly, we would like to thank the Shkur and Wong Family for providing us with necessary materials and believing in the two of us. Without the support of these outstanding individuals this project would not have been successful.
REFERENCES
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ABOUT THE AUTHORS
Ashki Shkur
My name is Ashki Shkur, I am a junior from Britannia Secondary. My family and I are from Kurdistan but moved to Canada in 2017. Growing up, I always had a passion for learning because I wanted to show that women have the power to make a difference and deserve the opportunity to receive an education. I love spending my free time giving back to my community by volunteering. I love science because it challenges our understanding and makes us more curious about the world. There is always something new and interesting to discover, and the journey to get there can be life-changing!
Candyce Wong
I'm Candyce Wong, and I'm in grade 10 enrolled at Britannia Secondary. I have a passion for learning all kinds of sciences and I love finding ways to make our world better. One fact about me is that I love participating in many extracurricular activities, such as volunteering for the community and as well as playing various sports. Last year in grade 10, I was a part of the Cross Country, Volleyball, Basketball, Badminton, and Ultimate Team.