The current use requires that wastewaters are efficiently treated to a standard where they can be safely discharged into the environment without further polluting it. Here are a few other aspects not widely known about sewage treatment in itself – they yield biogas. This gas can be used as a source of renewable energy, making sewage treatment plants about not just water purification but also the generation of eco-friendly power. These are the ‘cleaning’ points of waste before it goes back to the environment. In this blog we will discuss about how is biogas produced in a sewage treatment plant.
What is Biogas?
Biogas is a gaseous product that contains methane (CH4) and carbon dioxide (CO2) in large proportion. It is made through a sequence of processes such as fermentation whereby organic substances similar to food waste and plant materials and the sewage waste are under conditions that lack oxygen. The biogas produced is flammable and can be used for cooking, heating, and in fact generating electricity.
In what ways is biogas produced in a STP?
Biogas production is a measure that is included in the process of treating sewage and it is operates in a sludge level. Sludge is the floating or fried waste leaving after wastewater treatment. In most of the new designed sewage treatment plants that are being developed around the world, that is just sludge that is dumped into a closed container ordinarily known as digester.
This process goes by the following:
1) Sludge collection: Sludge is the leftover solid waste called for after sewage is treated.
2) Transfer to the Digester: Sludge is moved into a large, watertight tank known as a digester. In this digester, bacteria, in the absence of oxygen, break down organic matter within the sludge. This process is known as anaerobic digestion.
3) Biogas Production: When the bacteria digest the sludge, they produce biogas, primarily methane and carbon dioxide.
4) Biogas Storage: Biogas is collected and stored for use.
This will reduce the volume of waste while converting it into a product-gas, biogas.
Importance of Biogas in Sewage Treatment Plants
Biogas production in sewage treatment plants is as important as useful in many ways:
1. Source of Renewable Energy
It is regarded as a renewable energy source because it is produced through waste material and there is no exhaustible supply of this. The biogas production can go on as long as there are wastes which can be used in production or in other words we can deduce that biogas is a renewable source of energy unlike the fossil energy sources.
2. Reduction of Greenhouse Gas Emissions
Solid waste, particularly organic solid wastes, undergoes decomposition which leads to the formation of methane and when this is released to the atmosphere, it forms methane. Methane is one of the most effective greenhouse gases and its presence in the atmosphere positively affects the greenhouse effect.
3. Waste-to-Energy Conversion
From waste, sewage treatment plants produce that cannot be useful directly- product-energy. This is to say that rather than just dumping the waste collected from homes and industries; its transformation also makes them generate something that can light homes, buildings and industries.
4. Reduces Reliance on Fossil fuels
The generation of energy from biogas prevents the utilization of fossil energy sources such as coal, oil, and gas in sewage treatment works. Thus, it helps in reducing the pollution levels and in generating energy in a more natural way.
Applications of Biogas
The Biogas, which is produced in the sewage treatment plants, can be used in the following ways:
1. Electricity Generation
Biogas may serve as a power source as well. The majority of the treatment stations involve wastewater use biogas generators to generate electricity for powering the station. The additional electricity, on occasion, is used to be supplied to a nearby distribution network to serve other communities.
2. Heating
Biogas is also used as a fuel for heating. This can burn the gas to provide heat for various purposes, such as heating buildings or water.
3. Cooking
Biogas can further be purified to replace natural gas as a cooking fuel. This is especially the case in rural locations, using biogas as cooking fuels.
4. Automobile Fuel
Through more processing, biogas can be upgraded to become a source of biomethane. This will serve as an alternative automobile fuel. Cleaner and greener alternative to normal diesel or gasoline.
How Biogas Increases the Efficiency of Wastewater Treatment
Not only is the environment benefited with this production of biogas, but the overall efficiency of wastewater treatment is also improved through such processes. Here’s how.
1. Sludge Voluminous Reduction
With anaerobic digestion, it’s important that many organic materials in sludge are broken down into a much smaller volume. The resulting residue is easier and less expensive to dispose of.
2. Source of Plant Operation Energy
Many sewage treatment plants use the biogas they produce to power their own plants. This saves the plant money on its energy cost and makes the facility more autonomous.
3. Generates Lower Toxic Waste
The digestate remaining after anaerobic digestion is less toxic and also easier to handle compared to unprocessed sludge. Sometimes it can even be used as fertilizer depending on its composition.
Disadvantages in Biogas Generation
Though biogas production in sewage treatment plants provides many advantages, some disadvantages also exist:
1. High Setup Costs
The setup required for the production of biogas, such as the digesters and storage tanks, is quite expensive. However, the output benefits often outweigh the costs in the long run.
2. Maintenance
Routine checks have to be carried out on the biogas producing systems in other to obtain the best results from the system. If this proper care is not administered then the usefulness of the system is lost and the amount of biogas produced is less.
3. Gas Purity
Biogas is not plain methane rather a gas which contains a blend of methane, carbon dioxide, hydrogen sulfide and water vapor. Since the biogas is to be used in various small applications such as operation of vehicles or for cooking, it has to be freed from the following.
Conclusion
The fact that there is biogas in the sewage treatment plants is an added bonus for everyone. It turns waste into a highly useful form of energy while encouraging global greenhouse emissions reduction and enhancement of efficiency of sewage treatment. With every plant adopting the biogas technology available today more so the benefits will shift to the environmental and economical benefits and thus biogas will be a resource of sustainable waste management.
We will be utilizing the energy of fuel stored in sewage and reduce our consumption of fossil fuel to move towards a clean and green future.
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