Biogas Digester – Working Principle and Benefits

Sustainable organic waste disposal is one of the many considerations you have to make when planning an eco-friendly lifestyle. Luckily, it’s much easier nowadays to get rid of organic waste without damaging the environment. In fact, you can use your biodegradable trash to generate renewable energy power for your household and this is all thanks to the biogas digester (or anaerobic digester). In this article, we will will highlight the working principle and key advantages of biogas digesters.

homemade biogas plant

How does a biogas digester work?

There are different types of biogas digester systems to choose from based on size, type, input, and output. Regardless of these differences, they all work the same, and we have nature to thank as the inspiration behind the mechanism.

The principle is simple: pour organic waste into an “inlet box” which is filled with water, and once the two mix together the organic material is broken down by natural-occurring microorganisms within the internal anaerobic environment.

The resulting liquid is released into the main chamber where it goes through a biological process called anaerobic digestion. From here, energy-rich biogas is released to produce energy for cooking, lighting, heating and power generation.

Biological Breakdown of Organic Waste in a Biogas Digester

The anaerobic digester contains microorganisms that decompose the organic matter that you put into the digester. This anaerobic digestion process takes place in four different stages that are designed to transform organic waste into biogas and digestate.

  1. First, the organic waste goes through the hydrolysis stage where the breakdown of carbohydrates and other organic polymers happens. This is in preparation for the next stage known as acidogenic bacteria.
  2. Acidogenic bacteria transforms amino acids and sugars into organic acids, hydrogen, carbon dioxide and ammonia.
  3. Next, you have acetogenic bacteria that transform the organic acids into carbon dioxide, ammonia, hydrogen, and acetic acid.
  4. During the final stage, methanogens transform the aforementioned elements into methane and carbon dioxide. This is what you see as the blue flammable substance that provides clean energy for your home.

To build or to buy a ready-made biogas digester

Generally, it’s better to purchase a ready-made biogas digester instead of building one from scratch. That’s because a prefabricated biodigester comes with its own heating source, thus saving on electrical costs. It also acts as a “greenhouse” to provide passive heating. That way, you don’t have to spend money to heat it up from the outside.

anaerobic digestion process

So long as it’s placed in an area with plenty of sunlight, a biogas digester should work flawlessly to process organic matter into biogas. Not forgetting that homemade biogas digesters are high maintenance and they don’t produce as much gas as professionally made models.

Now, if you want to experiment on a small-scale just to prove the concept, you can always build a small biogas digester. It won’t produce a lot of gas and it’ll probably cause more problems down the road but it’s a good start.

If you want to use biogas to power an entire household, then you should invest in something that’s going to work hassle-free for years to come. You can feed your household anaerobic digester with food waste, grass clippings, and even cow manure.

Benefits of a Biogas Digester

Saves on electricity costs

With a biogas digester, you can take food waste from your kitchen and turn it into clean energy for your home! Once the system accumulates enough biogas, it produces a flammable gas that you can use to power your kitchen appliances, lights, and much more.

Produces high-quality organic manure

Another useful component of the biodigester is the slurry from the digested material. This odorless substance (also known as digestate) provides rich, organic manure for your garden. It comes out of the biogas plant through fermentation and can be used to fertilize vegetables, crops, and fruits.

schematic of rural biogas plant

Easy to use

The main system is actually super easy to use. Simply open up the faucet, throw your waste into the inlet and the system will do the rest, granted it’s already set up and ready to work.  Within a few hours, you’ll have biogas ready for cooking and other applications.

It’s eco-friendly

A home biogas system enables you to effectively and efficiently recycle organic waste. This helps to minimize organic waste and prevents harmful gases from polluting the atmosphere.

Conclusion

A biogas digester creates an anaerobic environment that allows for the release of energy-rich methane from the biological decomposition of organic waste. The result is a flammable biogas that can be used as a clean energy source in your home.


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About Salman Zafar

Salman Zafar is the CEO/Founder of BioEnergy Consult, and an international consultant, advisor and trainer with expertise in waste management, biomass energy, waste-to-energy, environment protection and resource conservation. He has successfully accomplished a wide range of projects in the areas of biogas technology, biomass energy, waste-to-energy, recycling and waste management. He is a prolific environmental writer, and has authored more than 2000 popular articles in reputed journals, magazines and websites. Salman can be reached at salman@bioenergyconsult.com

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