Making your own biogas sounds overwhelming.
There are some tricky bits, such as how you have to buy the right tools, but the process will make you feel like a million bucks by the end of it because you’ll be able to provide your own gas.
What can you use biogas for?
Biogas can be used for a variety of purposes, such as to provide heat. An excellent use for DIY biogas is to cook with it.
Before you can start making biogas, however, you need to make a digester. This is basically where the magic of making gas happens! So, with that in mind, let’s take a look at how biogas digesters work, followed by steps you need to follow when making your own biogas at home.
What, Exactly, Is Biogas?
Biogas is gas that’s produced from organic waste, such as animal waste and food scraps.
When these break down with the help of bacteria, they ferment and release gases such as methane as well as carbon dioxide. Methane that’s present in biogas is flammable, which means that it can be used to provide you with energy.
How Does A Biogas Digester Work?
Basically, a biogas digester is the body of the biogas system. You put organic matter inside the digester so that it can stimulate bacterial growth and decompose the matter. This process converts the waste into biogas that you can use.
So, to make your own biogas system, you’ll need to ensure you have a tank you can use as the digester, a PVC pipe that will be your inlet pipe that you’ll use for putting the waste inside the digester, and then a storage tank where the gas will be produced.
You’ll also need an outlet for the digested matter as well as a gas pipe.
What Are The Steps To Make Biogas?
Ready to make your own biogas digester?
These are the steps to follow, starting with all the items you need to collect. Luckily, you might have some of these hanging around your home or garage.
Step One: Items You Will Need
- Digester tank – make it approximately 700 liters in capacity.
- 3-foot long PVC pipe that is 3 inches in diameter. This is your inlet pipe that will carry the waste into the digester.
- 2-feet long PVC pipe that’s 3 inches in diameter. This is your outlet pipe.
- PVC pipe adapter (this will become your funnel for the inlet pipe)
- 2 plastic pipes (these will be your gas pipes)
- Gas valve
- Super glue
- Soldering iron
- Hacksaw blade
- Tyre tube
Step Two: Attach The PVC Pipes To The Tank
Set your digester tank wherever you want it to be located. An important tip is to put it in a sunny area as this will encourage bacteria to grow and consume the organic waste that you’ll put in it.
Then, take your inlet PVC pipe and place it on the side of the tank. With a marker, draw around the pipe so that you can cut a hole in the tank that will fit the pipe. You can then cut the hole with your soldering iron. Once you have inserted the PVC pipe into the tank, let it touch the bottom but don’t attach it to the tank.
Step Three: Attach Your Outlet Pipe
Now, on the other side of the tank, you want to make a hole for the PVC pipe that will be an outlet pipe to eliminate any excess slurry that’s produced in the digester tank. Use the same instructions as outlined in the previous step, with making the hole and then cutting it out with your soldering iron.
You will also need to make a smaller hole for your gas pipe.
Pro tip: Ideally, your waste inlet pipe should be larger than the hole you’ve made for your gas. This will make it easier for you to drop more waste into the inlet pipe.
Step Four: Seal The Inlet Pipe
The inlet pipe that you’ve attached to the digester tank will have small gaps where the pipe is inserted into the tank, so you want to seal these up. That’s where the use of super glue and a bit of sand will come in handy to prevent any gas from escaping.
Step Five: Attach The Gas Valve
You can now go ahead and attach your gas valve to your gas pipe. Make sure the valve is airtight as this will prevent gas from leaking.
With the use of a T-connector, you will then connect that gas pipe to another pipe. One end of that pipe will be connected to your burner or stove where you will use the gas that’s produced, and the other will be placed into a tyre tube. This is where your gas will collect. You can view more about how to do this by checking out the Pak Science Club video.
Step Six: Attach The Funnel
Don’t forget to attach the funnel onto your inlet pipe! This will make it much easier for you to drop organic matter into the digester.
Step Seven: Make Size Adjustments To Your Biogas System
When reading this guide, you will probably realize that you need to ensure that your tank is large enough for your biogas needs, depending on how much waste matter you are hoping to put into it on a daily basis.
So, you’ll have to adjust the size of your tank in order to accommodate how much organic waste you produce.
You’ll also need to adjust the length of your pipes. Bear in mind that to connect your gas pipe to your stove in order to use it for cooking, you’ll have to keep it in close proximity to your kitchen or make use of an outdoor stove.
How To Test For Leaks In Your Biogas Digester
As we mentioned in the steps earlier, your tank must be airtight to prevent gas from leaking out of it and going to waste.
Ensuring that your tank is completely airtight will also prevent foul smells from being released, and ultimately ensure that your biogas digester is working properly. Bacteria needs anaerobic conditions in order to grow, meaning that it has to be free of oxygen!
If biogas leaks, it can also be a safety risk, especially in areas that lack proper ventilation. To avoid any potential dangers, you need to test if your tank is airtight. Here’s how.
- Remove your fittings so that you can fill the tank with water. Make sure you fill it all the way to the top.
- Close the valve and replace the plug of the waste hole (inlet pipe). If you notice water leaking anywhere, make a note of it so you can single out the leaks that are present and fix them later.
- Turn the drum or tank over onto its side so you can see if there are any other leaks. Make a note of these on the tank by marking them.
- Empty the drum of water and let it dry.
- Once it’s dried properly, you can patch up any gaps or holes in the tank with paint or tar.
- Then, repeat the entire process of filling the tank with water and checking it for leaks. If you’ve sealed up the leaks correctly, then you’ll only have to do this process once!
What can be used in a biogas digester?
You can use a variety of organic waste in your biogas digester. Food scraps, such as vegetables, fruit, meat, and dairy can all be used, unlike in your compost. You can also use animal manure in your biogas digester to create gas.
How much gas can a biogas digester produce?
This will depend on how much waste you put into the digester and how big your digester is.
But, it’s said that a 275-gallon digester would make 275 gallons of biogas a few days after being fed organic waste. This is a bucket’s worth of waste (approximately five gallons), as Solar Cities reports.
How do you connect your DIY biogas system to your stove?
It’s important to note that you will need to purchase a stove that’s specially made to run on biogas for this to work.
Being able to produce your own gas puts you at a serious advantage.
Although you might feel overwhelmed by the thought of making your own biogas plant at home, as you can see in this guide it can easily be done. It’s definitely worth it – just think of all the biogas you’ll be able to produce and use!