Fourth Official Post
What are some ways in which we can get rid of waste materials? A common way is to dispose them in a landfill. Another way is incineration. However, Anaerobic Digestion is a better way as it reduces negative effects to Earth by reducing greenhouse gasses.
Most countries set aside abandoned quarries or unused ones to create landfills. A well-maintained landfill will be cheap and hygienic but what if it is not? Those which are older or not well-managed will create environmental problems. Wind may blow litter away and disease-carrying pests might be attracted. Landfill also creates one very common product: greenhouse gas which mostly consists of methane and carbon dioxide. This is created when the waste breaks down anaerobically uncontrolled. The gas can be deadly, killing vegetation on the surface and worsening the conditions of global warming.
Thermal treatment or incineration is a way which involves the combustion of the materials. It will convert them into heat, gas, steam and ash. It is commonly found in countries where land is scarce as it requires lesser area than landfill-method. However, the combustion is not perfect and organics such as dioxins may be created in the incinerator. This may cause significant environmental problems in the area near the incinerator.
Landfill gas can actually cause explosions and fire and even contaminate the groundwater. However, in Anaerobic Digestion, the methane produced can be used to replace energy from fossil fuels. In landfills, the greenhouse gas will escape into the atmosphere after naturally being digested by anaerobic digesters. This is not the case in Anaerobic Digestion as the gas will not be able to escape. In addition, combustion is not required. Combustion will increase the level of carbon dioxide in the atmosphere.
Anaerobic Digestion also conserves the Earth by reducing the emission of greenhouse gasses in a few other key ways:
Reducing vehicles movements
Reducing electrical grid transportation losses
All these prove that Anaerobic Digestion can help save the Earth in so many ways and benefit us greatly.
Thursday, July 9, 2009
Tuesday, July 7, 2009
Treating of wastewater
Fourth Official Post
Anaerobic Digestion is widely used to treat wastewater as it provides volume and mass reduction of the input material.
The water can come from the moisture content of the initial waste which was treated as well as the water which was produced in the microbial reactions.
After the Anaerobic Digestion, the waste water which comes out normally has increased levels of biochemical oxygen demand (BOD) and chemical oxygen demand (COD). This implies that the water has the potential to pollute the environment. Some may be named ‘hard COD’ as they cannot be converted by anaerobic bacteria onto biogas.
If this water is not treated and immediately mixed into watercourses, it will cause eutrophication. Eutrophication means an increase in compounds which contain nitrogen or phosphorus and causing more decay. It will cause a lack of oxygen and significantly reduce water quality and the population of organisms living in the water. Thus, further treatment is required and it normally will be an oxidation stage before it can be released.
Anaerobic Digestion helps by treating wastewater like Chlorination or the use of Ultraviolet (UV) light. Imagine that wastewater from industrials or housing estates is not treated and discharged into the oceans. Anaerobic Digestion also requires shorter retention time which means smaller tanks. Furthermore, it can also produce biogas. This is why anaerobic processes are widely used to treat wastewater even though it still requires further treatment after the processes.
Anaerobic Digestion is widely used to treat wastewater as it provides volume and mass reduction of the input material.
The water can come from the moisture content of the initial waste which was treated as well as the water which was produced in the microbial reactions.
After the Anaerobic Digestion, the waste water which comes out normally has increased levels of biochemical oxygen demand (BOD) and chemical oxygen demand (COD). This implies that the water has the potential to pollute the environment. Some may be named ‘hard COD’ as they cannot be converted by anaerobic bacteria onto biogas.
If this water is not treated and immediately mixed into watercourses, it will cause eutrophication. Eutrophication means an increase in compounds which contain nitrogen or phosphorus and causing more decay. It will cause a lack of oxygen and significantly reduce water quality and the population of organisms living in the water. Thus, further treatment is required and it normally will be an oxidation stage before it can be released.
Anaerobic Digestion helps by treating wastewater like Chlorination or the use of Ultraviolet (UV) light. Imagine that wastewater from industrials or housing estates is not treated and discharged into the oceans. Anaerobic Digestion also requires shorter retention time which means smaller tanks. Furthermore, it can also produce biogas. This is why anaerobic processes are widely used to treat wastewater even though it still requires further treatment after the processes.
Sunday, July 5, 2009
The current situation of Earth
Second Official Post
Before we continue to see what benefits Anaerobic Digestion can provide to the Earth, let us understand the current situation of Earth first. Earth is surrounded by a layer of gases that is retained by its gravity.
Humans evolve and develop higher technologies and this leads to the creation of many items. However, everything has its pros and cons. Humans, while evolving, is polluting the air. Air pollution causes harm to both organisms and the Earth’s atmosphere. It is actually the main cause of many respiratory diseases and deaths.
Emission is the emitting of radiation by objects. The hotter an object, the more radiation it will emit but its wavelengths will be shorter and vice-versus. The atmosphere emits infrared radiation and so it acts as a ‘blanket’ to control the amount of radiation Earth is losing to space. This is the cause of greenhouse effect as well. Humans are releasing too much greenhouse gasses into the air and all these will become the ‘blanket’. Therefore, when sunlight heats the Earth’s surface, these gasses will prevent the infrared radiation from going back into space. This warms up the Earth and causes global warming, leading to a climate change on Earth.
As humans develop, they tend to require more than the past. Fossil fuels are fuels formed by the anaerobic decomposition of dead organisms buried underground. Fossil fuels when burned are able to supply us with large amounts of energy. Humans are using them to produce electricity etc. The demands for the non-renewable fossil fuels are increasing as time passes. The rate of using fossil fuels is much higher than the rate of new ones being formed as they require millions of years to form. The combustion of fossil fuels in fact accounts for 90% of the greenhouse gasses. Knowing that fossil fuels may deplete one day, humans are trying to use renewable resources instead.
(An example of coal)
Humans need to protect and save the Earth or they will lose a place to live in. This is a major concern of many and so Anaerobic Digestion can actually resolves the above mentioned problems. That is why some countries like Germany and continental Europe are applying Anaerobic Digestion.
Before we continue to see what benefits Anaerobic Digestion can provide to the Earth, let us understand the current situation of Earth first. Earth is surrounded by a layer of gases that is retained by its gravity.
Humans evolve and develop higher technologies and this leads to the creation of many items. However, everything has its pros and cons. Humans, while evolving, is polluting the air. Air pollution causes harm to both organisms and the Earth’s atmosphere. It is actually the main cause of many respiratory diseases and deaths.
Emission is the emitting of radiation by objects. The hotter an object, the more radiation it will emit but its wavelengths will be shorter and vice-versus. The atmosphere emits infrared radiation and so it acts as a ‘blanket’ to control the amount of radiation Earth is losing to space. This is the cause of greenhouse effect as well. Humans are releasing too much greenhouse gasses into the air and all these will become the ‘blanket’. Therefore, when sunlight heats the Earth’s surface, these gasses will prevent the infrared radiation from going back into space. This warms up the Earth and causes global warming, leading to a climate change on Earth.
As humans develop, they tend to require more than the past. Fossil fuels are fuels formed by the anaerobic decomposition of dead organisms buried underground. Fossil fuels when burned are able to supply us with large amounts of energy. Humans are using them to produce electricity etc. The demands for the non-renewable fossil fuels are increasing as time passes. The rate of using fossil fuels is much higher than the rate of new ones being formed as they require millions of years to form. The combustion of fossil fuels in fact accounts for 90% of the greenhouse gasses. Knowing that fossil fuels may deplete one day, humans are trying to use renewable resources instead.
(An example of coal)
Humans need to protect and save the Earth or they will lose a place to live in. This is a major concern of many and so Anaerobic Digestion can actually resolves the above mentioned problems. That is why some countries like Germany and continental Europe are applying Anaerobic Digestion.
What is Anaerobic Digestion?
First Official Post
My research question is how does Anaerobic Digestion benefit the Earth and us, but first, what exactly is Anaerobic Digestion? I will be talking about it in my first post. Before that, let me give an overview of everything.
How does Anaerobic Digestion benefit the Earth and us?
Post 1. What is Anaerobic Digestion?
Post 2. The current situation of Earth
Post 3. Treating of wastewater
Post 4. Reducing the emission of greenhouse gasses
Post 5. Biogas- Renewable source of energy
Post 6. Digestate- Fertilizer
Post 7. Conclusion
Anaerobic Digestion is similar to the digestion which takes place in our body. However, rather than digesting food, it digests biodegradable materials. These materials will be broken down by microorganisms in a chain of processes.
Anaerobic Digestion can be used to treat wastewater and organic waste. It also reduces the emission of landfill gas into the air and is a renewable energy source. It may be used as fertilizer as well. These are the few advantages of Anaerobic Digestion. I will be talking more about all these in the next few posts.
Anaerobic Digestion is actually recognized by the United Nations Development Programme. The few microorganisms involved in the whole process are acetic acid-forming bacteria (acetogens) and methane-forming archaea (methanogens). A number of processes will convert the initial input material into intermediate molecules like sugars, hydrogen and acetic acid by allowing the organism to feed on them. Biogas will be produced in the end.
Similarly to the aerobic system, the microorganisms in the Anaerobic system also requires oxygen to survive and reproduce. The organic material itself or the inorganic oxides within it will provide the oxygen.
So what exactly are the processes? The 4 important biological and chemical key stages of Anaerobic Digestion are:
1. Hydrolysis
2. Acidogenesis
3. Acetogenesis
4. Methanogenesis
(A diagram is provided on the next page to facilitate understanding)
In order for the bacteria to access the energy in the input material, the material must be broken down first. Hydrolysis is like the stage whereby enzymes in our bodies break down food into smaller pieces in our mouth. Similarly, after hydrolysis, the complex and large molecules will be broken down into simple sugars, amino acids and fatty acids.
Using acidogenic (fermentative) bacteria, acidogenesis goes on to break down the remaining components.
A simplified chemical equation for the whole process: C6H12O6 → 3CO2 + 3CH4
At the third stage, the simple products produced at the second stage will be digested by acetogens, producing largely acetic acid together with hydrogen and carbon dioxide.
Lastly, methanogens will convert everything into methane, carbon dioxide and water. These end-products form the bulk of the produced biogas. The indigestible remnants will form the digestate.
My research question is how does Anaerobic Digestion benefit the Earth and us, but first, what exactly is Anaerobic Digestion? I will be talking about it in my first post. Before that, let me give an overview of everything.
How does Anaerobic Digestion benefit the Earth and us?
Post 1. What is Anaerobic Digestion?
Post 2. The current situation of Earth
Post 3. Treating of wastewater
Post 4. Reducing the emission of greenhouse gasses
Post 5. Biogas- Renewable source of energy
Post 6. Digestate- Fertilizer
Post 7. Conclusion
Anaerobic Digestion is similar to the digestion which takes place in our body. However, rather than digesting food, it digests biodegradable materials. These materials will be broken down by microorganisms in a chain of processes.
Anaerobic Digestion can be used to treat wastewater and organic waste. It also reduces the emission of landfill gas into the air and is a renewable energy source. It may be used as fertilizer as well. These are the few advantages of Anaerobic Digestion. I will be talking more about all these in the next few posts.
Anaerobic Digestion is actually recognized by the United Nations Development Programme. The few microorganisms involved in the whole process are acetic acid-forming bacteria (acetogens) and methane-forming archaea (methanogens). A number of processes will convert the initial input material into intermediate molecules like sugars, hydrogen and acetic acid by allowing the organism to feed on them. Biogas will be produced in the end.
Similarly to the aerobic system, the microorganisms in the Anaerobic system also requires oxygen to survive and reproduce. The organic material itself or the inorganic oxides within it will provide the oxygen.
So what exactly are the processes? The 4 important biological and chemical key stages of Anaerobic Digestion are:
1. Hydrolysis
2. Acidogenesis
3. Acetogenesis
4. Methanogenesis
(A diagram is provided on the next page to facilitate understanding)
In order for the bacteria to access the energy in the input material, the material must be broken down first. Hydrolysis is like the stage whereby enzymes in our bodies break down food into smaller pieces in our mouth. Similarly, after hydrolysis, the complex and large molecules will be broken down into simple sugars, amino acids and fatty acids.
Using acidogenic (fermentative) bacteria, acidogenesis goes on to break down the remaining components.
A simplified chemical equation for the whole process: C6H12O6 → 3CO2 + 3CH4
At the third stage, the simple products produced at the second stage will be digested by acetogens, producing largely acetic acid together with hydrogen and carbon dioxide.
Lastly, methanogens will convert everything into methane, carbon dioxide and water. These end-products form the bulk of the produced biogas. The indigestible remnants will form the digestate.
My First Unofficial Post- Introducing my research question
I had done some simple research and came up with a research question. The question is: How does Anaerobic Digestion benefit the Earth and us? I decided to continue on this topic as Anaerobic Digestion is something which I have never heard of. It should be quite interesting. In my next post, I shall start by giving an overview and explain what Anaerobic Digestoin is and how it works?
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