I have been searching for some method of using the food waste, decomposable organic material and kitchen waste efficiently, and came across information on producing bio-gas from organic waste.

The bio-gas produced from food waste, decomposable organic material and kitchen waste, consisting of methane and a little amount of carbon di oxide is an alternative fuel for cooking gas (LPG). Also, the waste materials can be disposed off efficiently without any odor or flies and the digested slurry from the bio-gas unit can be used as an organic manure in the garden.

Components of the Bio-gas Plant

The major components of the bio-gas plant are a digester tank, an inlet for feeding the kitchen waste, gas holder tank, an outlet for the digested slurry and the gas delivery system for taking out and utilizing the produced gas.

This project is also useful for students to have a hands-on learning experience in constructing a Mini Bio-Gas Plant, using locally available material.

Material Required:

1. Empty PVC can 50 ltrs capacity: 1 No. (to be used as Digester Tank)
2. Empty PVC can 40 ltrs capacity: 1 no. (to be used as Gas Holder Tank) (Make sure the smaller can fits inside larger one and moves freely)
3. 64 mm dia pvc pipe: about 40 cm long (to be used for feeding waste material)
4. 32 mm dia pvc pipe: about 50 cm long (fixed inside gas holder tank as a guide pipe)
5. 25 mm dia pvc pipe: about 75 cm long (fixed inside the digester tank as a guide pipe)
6. 32 mm dia pvc pipe: about 25 cm long (fixed on digester tank to act as outlet for digested slurry)
7. M-seal or any water-proof adeshive
8. Gas outlet system: Please see Step 4 below for required materials and construction

Tools required

Do not require many tools here. A hack saw blade for cutting the cans & pipes and a sharp knife for cutting holes on the cans are all the tools we need.

Additional accessories

A single burner bio-gas stove or a Bunsen Burner used in school laboratories

Step 1:

Bought this 50 ltrs capacity PVC can, which will act as the digester unit and removed the top portion of the can, by cutting it with a hack saw blade:

Step 2:

The smaller white can, which will act as the gas holder fits inside the red one. Here, again removed the top of the white can, also with the help of a hack saw blade:

Step 3:

64 mm, 32 mm and 25 mm dia PVC pipes which  will be used for feeding the kitchen waste, guide pipe for the gas holder and guide pipe fixed with the digestion chamber respectively. A small piece of 32 mm dia pipe will be used as outlet for the slurry:

Step 4:

  1. items required for the gas delivery system: got these items from a hardware store

1. Ball valve : one no ( to adjust the gas flow)
2. 'T' joint : one no ( to connect the gas holder and the ball valve)
3. Cap to block one end of 'T' joint : one no
4. Coupling or Adapter : one no (to connect vertical end of 'T' in to the gas collector)
5. Nipple: one no (added to the coupling in to the gas collector)
6. Gas pipe (flexible) : two meters
7. Barb : one no (fitted with the gas pipe, to join with the Ball valve)
8. Clip : one no (used for crimping the barb with the gas pipe and make it leak-proof)
9. Teflon tape : one roll (used as thread tape in all joints)

Step 5:

Here I have marked the cuts to be made in the bottom of the gas collection tank. The smaller hole on the left for gas delivery system, center hole for fixing the 32 mm guide pipe and 64 mm hole for fixing the waste feeding pipe on the right side. Made these holes with the help of a sharp knife and hack saw blade.

The next image is Inside of the gas holder showing the 32 mm guide pipe (center) and the 64 mm feeding pipe fixed with M-seal

Step 6:

Top view of the gas holder showing the feeding pipe, central guide pipe and the gas delivery system: I have closed the feeding pipe withe an old lid  (red one). This will facilitate opening the feed pipe only during feeding the system.

Step 7:

Digestion tank fitted with the central guide pipe and the outlet pipe for the slurry:

Step 8:

Completed unit. I have removed the gas pipe, so that the joints will get cured without any stress:

Wait for a day or two before feeding the system, allowing all joints to get cured and become leak-proof.

Initially, cow-dung mixed with water will be fed in to the system, which will start the gas formation process. Subsequently, food waste, decomposable organic material and kitchen waste will be diluted with water and used to feed the system. The gas holder will rise along the guide pipes based on the amount of gas produced. We can add some weight on top of the gas holder to increase the gas pressure. When we feed the system, the excess digested slurry will fall out through the outlet pipe, which can be collected, diluted and used as organic manure.

Initial production of gas will consist of oxygen, methane, carbon di oxide and some other gases and will not burn. These gases can be released to the atmosphere by opening the ball valve at least three / four times.

Subsequent gas will consist of about 70 to 80 percent methane and the rest carbon di oxide, which can be used in a single bio-gas burning stove or a Bunsen burner.

Total cost of this proto-type system is about one thousand Indian Rupees (about 20 dollars)

This is a basic prototype of a Bio-gas system using the food waste, decomposable organic material and kitchen waste to produce gas. An one thousand litre capacity Digestion tank will be sufficient for a small household for daily cooking purpose. The bigger commercial models provide a water seal between the digestion tank and gas holder tank.

You can get further information on kitchen waste based mini Bio-gas plant at the following links:



Step 9:

Charged the digester tank with cow dung diluted with water. Placed the gas holder tank and left it for two three days. The cow dung slurry started the process of gas forming.

Gas formation started and the gas holder tank gets lifted up. I have placed two bricks on top of the gas holder to get more gas pressure.

Step 10:

Note for students who are doing this as their School Project:

1. Take guidance from your teacher while using the gas in a stove or Bunsen burner.
2. Collect surplus food and wastage during lunch, dilute and feed the system.
3. Fruit peels, extracted tea powder, waste milk and milk products  can also be used for feeding the system.
4. DO NOT USE eggshells, Onion peels or left-over bones in this system as they will affect the efficient functioning of the system
5. Plant some seedling
6. while feeding, collect the slurry from the outlet, feed the seedlings and watch them grow
<p>sir is there any way to measure the efficiency of biogas plant ? how can we know the efficiency of biogas plant ?</p>
Please see Step 6 of my other instructable where I did some rough calculations comparing with LPG consumption. But it is very rough estimation only and not accurate<br><br>https://www.instructables.com/id/Make-Energy-From-Weeds/
<p>Hello Sir,</p><p> Please send this PDF to iraiyavan@yahoo.com</p><p> Please send me your contact details. We wish to see the medium sized biogas plant directly. We will come to your place with your appointment. Thanks. </p>
Where are you from ? Please give your location and I will guide you with routes and contact information
<p>I also trying to make a small black colour plastic hut around the digester so that it can trap the sun heat and makes the digester around hotter. <a href="http://batteryrecover.com" rel="nofollow">HERE</a> is very good guide for everyone who needs energy for home devices. Thank you antoniraj!</p>
<p>so does that black hut works fine for your plant ? have you able to increase the formation rate of biogas ?</p>
Hello sir, thanks for this tutorial it is really interesting ! Do we necessary have to wait for the initial gas to be produced before we start feeding with kitchen waste ? Again does the biogas digester have to be completely full of the mexiture ?
Initial gas will be produced within 3 to 4 days of feeding with cow dung. It is better to wait for few days before feeding kitchen waste as the microorganisms in the cow dung will multiply and become active.<br><br>Initially, fill the digester to about 1/3 to 1/2 of its capacity. Once the gas production starts you can feed the tank with kitchen waste. There will not be any output slurry till the digester gets filled. Once it is full the digester slurry will be drained out whenever you feed the tank
Thank you very much. I appreciate your quick support.
<p>hi like to this for as a small scale industries can you help me to guide sir</p>
Please go through my other instructable on how to construct a medium sized Biogas Plant at this link. You can make one as per your requirement<br><br>https://www.instructables.com/id/Constructing-a-Medium-Sized-Biogas-Plant-Using-Kit/
I'm a building contractor I'm planning to construct a biogas plant for my labours. They are nearly 15 members.
<p>you need to build a large scale system to serve 15 members. Please go through my other instructable on how to construct a medium sized Biogas plant at the following link. This provides 50 % gas requirement for a family of 5 persons</p><p>https://www.instructables.com/id/Constructing-a-Medium-Sized-Biogas-Plant-Using-Kit/#comment-list</p>
Could i get ur contact number sir
Is this the same method tat i want to use sir
Hi sir
Hello sir,this is sai. I make a biodigester 20 days back in my home with 220ltrs drum. Now its produce the gas. but its not flameble(ignite). Plz help me sir.my mail id: lynin.sairam@gmail.com
The gas produced initially will not burn properly as it contains less methane and other impurities. Release the gas few times from the gas holder till you get burnable gas. Start feeding the plant regularly with kitchen waste or other organic material.<br><br>Please go through my other instructables on Biogas for more information at the following links<br><br>https://www.instructables.com/id/Constructing-a-Medium-Sized-Biogas-Plant-Using-Kit/<br><br>and<br><br>https://www.instructables.com/id/Make-Energy-From-Weeds/
<p>Looking at step 7 I see you had used the M-seal to hold the guide pipe 25mm dia pvc pipe. However my question is, how would the other gas that are not methane go up to that pipe if its fully sealed? Did you made a small hole at the bottom or am I wrong?</p>
The guide pipe should be completely sealed and should not allow any gas to pass through even if there are other gasses. There should not be any hole at the bottom also. The purpose of the guide pipe is to keep the gas holder in vertical position. Without the guide pipe, the gas holder tank will tilt to one side.
sir, kitchen waste or food waste having the C:N , 15:1 but the ideal C:N ratio for bio-gas production should be 25:1 so my question is will it effect bio-gas production upto any extent and if yes so what we need to do to solve it ?
I am having a medium sized Biogas plant producing regular gas for more than two years. we feed all kitchen / food and garden waste regularly and the gas production never seems to be affected by the kind of material we feed. Anyhow, how do you find out the C:N ratio of your feed material without proper equipment ?
<p>this food ratio was i found in some books as a stander for kitchen waste that's why i asked you sir,</p>
<p>you can go through these books to see any mention of how they can determine the C:N ratio of food waste</p>
<p>No sir the there is no any article which shows how to find or determine the C:N ratio of organic matters, if i get i will share with you sir</p>
<p>hello sir,</p><p>can i use aluminium dig ester coated with black co lour instead of FRP digester ? i think metal can increase the temperature inside the chamber</p>
<p>Hello sir every time we need cow dunk or first time only because i live in city area.every time cow dunk is not available.from only wastage item from kitchen,organic things,fruit peels can be made or not please clear me.</p>
<p>only starting time we need cow dung than after there is no need of cow dung to run bio-gas plant unless bacteria inside the digester died.</p>
There is no need to use cow dung slurry every time. it is required only during the first time to start the digestion process. Afterwards you can all kitchen, food and organic wastes directly in the digester
<p>hell sir,what is the different between decomposable &amp; decompostable materials.i search the list of decomposable items on net but net shows compostable items only.are they same or diffirent ? </p>
<p>sir i am very interested for this job,by this method we get success or it is only try.could you please clearly mention that which which things can we use for this job.</p>
<p>this is a working prototype being used to explain how the biogas digester works</p>
I could not reply to you earlier as my system was down.<br><br>Using any metal bodies as digester or gas holder is not advisable. About 40 years back, during the initial stages of Biogas plants in India, they used metal sheets for the gas holder, but none of them are functioning now. The reason metal got eroded in the slurry and gas started leaking.
<p>Thank you, sir</p>
AJAY KHEDKAR:<br>hello sir, i am civil engineering student from INDIA.I am doing my final year project on clean and green energy village under which we are designing Bio Gas plant for village and we require your support for that <br> 1.what are standard design steps for Bio gas plant design? <br> 2.what are various material can be used instead of cow dung?<br> also plz give your innovative suggestion for CLEAN AND GREEN ENERGIES that can be use in villages
Please go through my other instructables on biogas at the following links<br><br>How to Build a Medium sized Biogas Plant<br><br>https://www.instructables.com/id/Constructing-a-Medium-Sized-Biogas-Plant-Using-Kit/<br><br>Make Energy from weeds<br><br>https://www.instructables.com/id/Make-Energy-From-Weeds/<br><br>You can also download more files like Designing the Biogas System and construction details larger fixed dome models from the Dropbox link below...<br><br>Designing Biogas System<br><br>https://www.dropbox.com/s/4v7s1vcbwg1uhti/Designing%20biogas%20system.pdf?dl=0<br><br>Balaji Biogas system<br><br>https://www.dropbox.com/s/dyzqhplp1bjtrnr/Balaji%20Biogas%20system.pdf?dl=0<br><br>Deenbandhu Type Biogas plant Construction Manual<br><br>https://www.dropbox.com/s/yc1mql1aoyrvz92/Constrution%20manual%20Deenbandhu%20type%20Bio-gas%20plant.pdf?dl=0
<p>Hello sir.That's really a very good idea.sir,I want to use biogas for heating in pyrolysis of plastics.I would like to know whether this plant can be use for this purpose?</p><p>thank you</p>
This is a prototype of a Biogas plant, which can not be used other than School Science projects
<p>Hello! I love your idea. I am going to use it for science fair this year, but we don't own a bio-gas stove. However, we do own a propane stove. Could that be used instead? Thanks a lot!</p>
You can not use a propane stove for Biogas. Instead use a Bunsen Burner which is available in almost all school laboratories, or you can buy it online. It is very cheap.
<p>Thank You!! I really appreciate your help!</p>
Hello am Allan from Uganda, but in our country we are eatting up the green cover. But i believe such knowledge ( biogass) will be a great deal for our locals , so wat am asking ,for a 100 Litre drum how much gobar is need and how much water is needed for the start and for how long will the gas produce? And is ther any catalysist to speed up the reaction? Thank very much
Fill the tank initially to about 1/3 with cow dung slurry. If you can fill with more cow dung, it is better. For 100 ltrs drum, use about 500 to 750 grams of material with about 2 ltrs of water. Gas production will start within few days. No catalysts are required to speed up the process
<p>Thank you very much sir, please how soon are you to change the waste material.</p>
You need not to change the waste material. Feed the digester regularly everyday and the digested slurry will be automatically drained out through the outlet pipe.
<p>Hello... i like this</p>
Thank you...
Hello sir,<br> Can I use wooden dust and chips to form slurry for biogas plant.
Do not use wooden dust and chips in the Biogas digester
<p>okey , Thank you sir , i will take your suggestion as my top most priority, but i want ask one more thing that for agriculture residue or soft wood waste like pine needles etc, should we need pre -digestion process ? or could we directly pore these kinds of waste into main dig ester after shredding? </p>

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Bio: I like to make things more simple with easily available resources. My favorite quote: A human being should be able to change a diaper, plan ... More »
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