Biogas can be produced from the anaerobic digestion of kitchen waste and cow dung. The optimal carbon to nitrogen ratio for biogas production is around 25:1, which can be achieved by mixing kitchen waste and cow dung. Biogas production occurs in three stages through the action of various microorganisms and produces a gas that is around 60% methane. Studies found that mixing cow dung with kitchen waste produced more biogas than using either substrate alone. Approximately 65,000 biogas plants have been installed in Bangladesh so far but more are needed to utilize available waste resources and provide renewable energy.

1. BIOGAS PRODUCTION
FROM KITCHEN WASTE
AND COW DUNG
Presented by :-
Deedarul Hyder Sani
Reg. No: 2014431001
GEB, SUST.

2. Biogas
The actual make-up depends on what is being decomposed
- Biogas is a combustible mixture
of gases.
- Chief constitute of biogas is
Methane.
Why Biogas?
-Renewable Energy
-High Calorific Value
-Clean Fuel
-Useful Byproduct

3. Characteristics of good raw materials
Raw materials:
Kitchen Waste Cow Dung
 Cooked Waste
 Uncooked Waste
-Proper C/N ratio
-Finer Particle size

4. Properties of Kitchen Waste & Cow Dung
Parameters Kitchen waste Cow dung
pH 4.27 7.5
NH3(mg/L) 42.7 30.1
Total solids(mg/L) 176728 588366
Volatile solids(mg/L) 158231 11400
Total Phosphorus(mg/L) 546 299.33
Characteristics of Kitchen waste and Cow dung
Cow Dung 20 : 1
Kitchen waste 12-20 : 1
Kitchen Waste + Cow Dung 25 : 1
C/N Ratio

5. Structure of a Biogas plant
Parts of Biogas plant :
Mixing tank
Inlet chamber
Outlet chamber
Digester
Gas holder

6. Biogas production takes place in 3 stages
• Hydrolysis & Acidogenesis
• Acetogenesis
• Methanogenesis
Polysaccharides, Amino acids,
Fatly acids (long chain)
Non-methane-producing bacteria
(1st stage)
Volatile fatty acids, Alcohols, Neutral
compounds, Hydrogen, carbon dioxide
Methane-producing bacteria &
Non-methane-producing bacteria
(2nd stage)
Acetic acid
CH4, C02, H2
Methane-producing bacteria &
Non-methane-producing bacteria
(3rd stage)
CH4 + C02
Groups of Microbes Involved in the
Three Stages of Biogas Fermentation
Biogas
microbes
Non-methane
producing
bacteria
Methane
producing
bacteria
Hydrogen-producing
acetogenic bacteria
Fermentative bacteria
Groups of Biogas Microbes

7. Factors in Biogas Production:
Basic Factor:
-Bacteria
-Food
-Contact
Environmental Factor:
-Temperature
-pH
-Toxicity

8. The Rate of Biogas Generation with Various Cooked Waste
Rate
Days
waste 10 20 30 40 50 60 70 80 90 100
100% Cooked
Waste
9.07 64.87 80.28 85.77 89.29 92.41 96.47 98.10 99.45 100.00
70% : 30%
Cow dung:Cooked
waste
2.63 6.28 7.62 11.63 31.06 51.80 61.28 70.68 87.24 100.00
50% : 50%
Cow dung :
Cooked waste
10.67 29.33 42.67 49.33 53.33 57.33 62.67 74.67 93.33 100.00
20% : 80%
Cow dung :
Cooked waste
8.42 40.00 54.74 61.05 66.25 60.47 73.68 84.21 94.73 100.00
Amount of biogas formation in a period of Time
(Expressed as a % of the total yield of biogas)

9. The Rate of Biogas Generation with Various Uncooked Waste
Rate
days
Waste
10 20 30 40 50 60 70 80 90 100
100% Cow Dung 12.12 31.91 47.39 69.50 87.97 95.41 97.45 98.62 99.44 100.00
70% : 30%
Cow dung :
Uncooked Waste
7.79 20.77 35.49 52.81 71.88 84.04 90.90 95.24 97.83 100.00
50% : 50%
Cow dung :
Uncooked waste
3.82 15.10 24.61 37.03 51.88 65.59 79.59 89.25 95.13 100.00
20% : 80%
Cow dung :
Uncooked waste
1.62 3.24 7.57 26.48 45.40 57.29 67.56 78.91 90.81 100.00
Amount of Biogas produced in a period of time
(Expressed as a % of the total yield of Biogas)

10. Burning capacity of Biogas from different
combination of substrates
Substrates Burning Capacity
100% Cooked Waste Not burn
100% Cow dung Burn well
50% Cow dung: 50% Cooked waste Burn slightly with reddish flame
70% Cow dung:30% Cooked waste Burn slightly
50% Cow dung:50% uncooked waste Burn well
70% Cow dung:30% Cooked waste Burn well
20% Cow dung:80% Uncooked waste Burn well

11. STATUS OF BIOGAS PLANT IN BANGLADESH
 Biogas pilot plant project implemented by IFRD
constructed 17200 Biogas plant (1995-2004)
 Public agencies with BCSIR constructed 30000
Biogas plants.
 Bangladesh Rural Advancement
Committee installed about 1200 Biogas plant.
 Grameen Shakti (GS) installed 13000 Biogas plants
as partner organization under IDCOL’s program
 Department of Environment installed about 260
Biogas plants.
 Overall 65,317 biogas plants installed within 31
December 2012.

12. Limitation of Biogas plant:
 High initial cost of installation.
 Inadequate technical support.
 Inadequate feed supply.
Safety measures:
 Regularly check the whole system for leaks.
 Provide ventilation around all gas lines.
 Always maintain a positive pressure in the system.
 No smoking or open flames near biogas digesters and gas storage.

13. References
• APH, 1989, The Biogas Technology in China. Chengdu Biogas Research Institute of the
Ministry of Agriculture, PRC
• Balch, WE. Fox, G.E., Magrum, LJ, Woese, C.R. and Wolfe, RS., 1979. "Methanogens reevaluation of a unique
biological group". Microbial reviews, 43: PP 260-296.
• Barker, HA 1956 "Bacterial Fermentation" CIBA Lectures in Microbial Biochemistry, Institute of Microbiology,
Rutgers, New Jersey, USA.
• BBS, 1994. Analytical Report on Bangladesh Population Census.
• Chowdhury, M .Y .1988 " Biomass and Bioferlilizer Production". A Research paper Presented at International
Seminar on Energy from Biomas Bangladesh Agricultural University, Mymensingh, Feb.27-19.
• Rahman, M.H., 1996: Biogas: environmental aspects and potential for generation in Bangladesh, Int. J. Env.
Educ. & Inf., UK.
• Unicef and DPHE, 1994: The status of rural water supply and sanitation in Bangladesh, Repot of Unicef and
Department of Public Health Engineering, Bangladesh.
• A. Al-muyeed, A. M. Shadullah, “Electrification through biogas”, forum, monthly publication of the daily star,
Dhaka, Bangladesh (2010), volume. 3, issue.1
• M. Islam, B. Salam and A. Mohajan , “Generation of biogas from anaerobic digestion of vegetable waste”,
Proceeding of the 8th International Conference on Mechanical Engineering (2009), 26- 28 December, Dhaka,
Bangladesh

14. Thank You 