Design and construction of mini biogas digester for family use

The biogas digester is composed of a green house made with hollow sunlight sheet and metal supporting frame, a membrane digester with a gas storage bag combined in one, a stainless steel sink, a stainless steel outlet, a biogas filter and a biogas booster pump:

1. Biogas production of 2m3/day is good enough for a family

2. It is a DIY kit small scale biogas system for convenient transport and easy assembly.

3. It is surface mounted, there is no need for digging or heavy construction.

4. It can be assembled within 2 hours by anyone with manual and video guidance.

5. Treated organic waste locally, use biogas for cooking, electricity or feed garden with nutritious liquid fertilizer.

6. Used for family, farm, restaurant, hotel, resort to treat organic waste, such as food waste, sewage sludge, animal waste.

7. Light weight and easy to install, packed in carton box.

8. Life span more than 10 years - made of stainless steel frame

9. Raw material of green house and PVC biogas storage bag

10. Specification 156*120*195cm

11. Methane Content 65% which is excellent for cooking

 

 

Construction video:

 

 

 

 More info:

DIY kit assemble mini biogas digester for family use

Need Biogas Now?

Get Your FREE Biogas DIY Training Right Here! 

Calculation of feeding ratio for 1000 liter biogas digester

To my understanding 1000 liter/40 = 25 liter. So it is advisable to feed 25 liter of food waste mixed with water. It means, your food waste is already included in that 25 liter. I have read from this elsewhere, the maximum ratio of food waste to water you can apply is 1:1 (though to me its too much for the microbes to handle). Roughly the maximum weight of food waste you can put is 12.5 kg in which you add another half of water to add up to 25 liter as total mixed. However its up to you what level of total solids you want to practice by reducing the food waste within that 25 liter. The more effluent you take out from the digester, the more bacteria you will discard and that may affect whole digestion process and becoming slower in producing gas.

Need Biogas Now?

Get Your FREE Biogas DIY Training Right Here! 

Construction of 45 liter biogas biodigester for beginner

To construct a simple biogas digester in the photo above is easy. The materials you need are readily available at any hardware store near your residential area.

Basically the system consist of:

1. Inoculum
2. Biogas biodigester
3. Biogas storage
4. Connection between biodigester and its biogas storage

Inoculum
Inoculum is a starter for the anerobic fermentation process to begin. It consist of consortium of microbes to help in digesting suitable raw material and able to turn them into biogas and effluent that is more environment friendly within a short period of time compared to conventional aerobic composting.

Biodigester

What is a biodigester? The function is to contain the fermentation process of food waste occurred in an aerobic condition without any oxygen.

Biogas storage
Used tyre tube to contain and store biogas produced from the fermentation.

Connector
A silicon clear host to connect gas produced from biodigester to the storage bag.

Other accessories and materials needed
PVC pipe, silicon gel, plastic and metal valve, etc.

Want to construct your own low cost biogas biodigester ? CLICK HERE!

Need Biogas Now?

Get Your FREE Biogas DIY Training Right Here! 

Inoculum preparation for biogas generation

The most cheapest and easiest way to produce an inoculum is using digestate from working biogas digester. They are consist of active culture with stable activity because consist of varieties of microbes working together or consortium.

Next source is by taking a scoop of slurry or sediment from anaerobic pond. These are also active microbes we can used directly to produce biogas.

If you happen to live nearby cattle farm, dung is another source of microbes that can produce biogas.But to start with cow dung we need to mix it with water and ferment until it mature in which produces biogas.

Do not mistaken biogas with carbon dioxide. Biogas is flammable while CO2 is not.

So to produce biogas you can start with things that already around you.

Want to construct your own biogas biodigester? Click here!

Need Biogas Now?

Get Your FREE Biogas DIY Training Right Here! 

HRT - hydraulic retention time is period taken for a waste to be digested to produce biogas completely at particular temperature

I am very lucky able to find old air temperature data at my place. The average is like 26.8 celcius. So, according to David David William House 's graph, the approximate HRT is 45 days. So, it is safer for me to decide to choose 50 days HRT for my digester. To determine how much to feed daily is by calculating = digester volume (liter) / HRT (day) = 200 liter/50 days = 4 liter/day. Again, rule of thumb do not get solid food waste over 50% of daily feeding volume. In my case for 4 liter feeding, 2 kg of food waste is the maximum volume then mix with 2 liter of water to a total of 4 liter. If you do not have confident and do not want to get your system sour lets try less than 50% food waste of your daily feeding volume. Please try and error, experiment with your system and you will learn a lot finding the most optimum condition to run your system. Want to construct your own biogas biodigester? Click here!

Low cost biogas digester design and lay out

I have always think of ways to recycle my kitchen wastes. Living in housing area with limited backyard space unable me to dig appropriate hole to bury all my kitchen waste without leaving smelly odor. I don't have any experience composting and food waste easily become smelly if you do not handle them properly. Then I came across anaerobic composting which is enclosed and used cow dung as starter. I feel this technique is practical and easy to construct. To make it interesting, I want to use a modified garbage bin and call it food waste recycle garbage bin just like when you throw your usual wastes into a dustbin but mine is a little bit different in which it can recycle organic wastes. That's how I came up with the idea.

Its not really difficult. Take a normal standard garbage bin at modified it a bit by installing inlet for feeding, outlet port for effluent and outlet valve for biogas to be collected into a tyre tube. Its that simple.

Then I built bigger module have an upgrade experience from my first biodigester as above. The new digester is 160 liter and connected to 500 liter biogas bag as storage. I also found how to modify a normal burner into a biogas burner.

Now I convinced that biogas generated at home really can be used for cooking.

Need Biogas Now?

Get Your FREE Biogas DIY Training Right Here! 

How to make biogas at home manual by David William House is worth to try (Recommended)

The first edition of the book quickly established itself as the book on biogas generation. Now in a newly revised edition, David House brings together all the information, from the most theoretical scientific research to grass roots homescale trial and error.Here are the detailed designs for generators and the knowledge, encouragement, imagination, and humor you will need to build a generator of your own. While biogas may not yet be a household word, you should consider it seriously if you believe in the future of alternative energy.

 
Use biogas for illumination, cooking, water heating, refrigeration, space heating, and to fuel vehicles.

*Over 100 figures and tables
*All the necessary formulas
*6 model generators and a design flow chart
*Complete list of resources
*Extensive bibliography

What is inside? Table of contents of Complete Biogas Handbook is as below:
I: Overviews
	1: This Book	2
	2: Energy	5
	3: Math	10
	4: Biology	14
II: Parameters		23
	5: The Airless World	24
	6: TS, VS, FS	25
	7: pH	26
	8: Temperature	31
	9: C/N	35
	10: Percentage of H2O	46
	11: HRT and Loading Rate	50
	12: Agitation	52
	13: Toxins	53
	14: Pressure and Surface Area	56
III: Substrates		58
	15: Purified Substances	59
	16: Manure Substrates	65
	17: Plant Substrates	73
	18: On Growing Substrates	80
IV: Uses		85
	19: Scrubbing	86
	20: Combustion	94
	21: Illumination	97
	22: Burner Design	101
	23: Cooking	103
	24: Water Heating	104
	25: Steam	110
	26: Refrigeration	112
	27: Engines	113
	28: Space Heating	121
	29: Gas Requirements	125
V: Troubleshooting		128
	30: Cultures	129
	31: Startup	131
	32: Scum	133
	33: Foaming	137
	34: Sediment	138
VI: Design		139
	35: Basic Generator Types	140
	36: Heating Generators	143
	37: Agitation	153
	38: Gas Handling	157
	39: Slurry and Effluent Handling	161
	40: Pumping	163
	41: Construction Materials	167
	42: Sizing Generators	169
	43: Safety	173
	44: Economics	176
	45: Design Process	181
VII: Plans		186
	46: Pipes and Drums	187
	47: Test Generator	197
	48: Modular Batch Generator	200
	49: Hybrid Generator	203
	50: Home Wastes Generator	208
	51: Continuous-Fed Fibrous Substrates Generator	211
VIII: Appendices		213
	Appendix 1: Analysis	213
	Appendix 2: Biohydrogen	217
	Appendix 3: Agricultural Use of Effluent	219
	Appendix 4: Math of Gas Production	223
	Appendix 5: Specific Gravity	227
	Appendix 6: Drill Statistics	228
	Appendix 7: Burner Design	231
	Appendix 8: Vital Statistics of Gases	233
	Appendix 9: K and C Values	235
	Appendix 10: Steam Temperature, Pressure, Water Depth	237
	Appendix 11: Heat Transfer in Pipes	238
	Appendix 12: Decimals and Fractions	241
	Appendix 13: Geometry, Trig	243
	Appendix 14: Metric Conversion	245
	Appendix 15: A Simple Method for Temperature Conversion	248
	Appendix 16: Terms	249
	Appendix 17: The Answers	253
	Appendix 18: Bibliography	259
	Appendix 19: Author’s Afterword	270
	Appendix 20: Contents, Figures, and Tables	272
	Appendix 21: Index and Authors	283

To get more info in depth about homemade biogas digester please read the manual below where you can get from Amazon.com.

.