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Campus Sustainability Project
Design
Theme :- Waste In Campus
Production Of Bio-Gas Using
Waste Food
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Needs Of Bio-Gas
Currently the fuel used for production ofelectricity are coal ,natural gas etc.
All these are non-renewable source ofenergy.
These sources are limited.
What if we are on the verge of extinction of
coal , natural gas???Biogas will be the best alternative for
production of electricity.
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Introduction to bio-gas
technologyBiogas refers to a gas made from anaerobic
digestion of agricultural and animal waste &
food waste.
Biogas can be obtained from any organic
materials after anaerobic fermentation by
three phases.
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1st Stage: Fermentative bacteria
Hydrolyze & ferments organicsubstance
Cellulosedecomposing
bacteria
-saccharides
Proteindecomposing
bacteria
-Amino acids
Fatdecomposing
bacteria
-fatty acids
Volatile acids,h2o & co2
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2nd Stage: Hydrogen producing
acetogenic bacteria
Decompose thesubstance
produced in firststage
Acetic acid,H2,CO2
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3rd Stage: Methane producing bacteria
Convert thesubstances
produced in 1st &2nd stage
CH4 & CO2
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All kinds of organic waste can be used in a biogas plant such as: kitchen waste
and garden waste, cattle dung and sewage.
The efficiency of the biogas production is affected by the following factors:
Carbon: Nitrogen-ratio, volatile solid content, loading rate, temperature, pH,toxicity, dilution, retention time and mixing.
The Carbon: Nitrogen-ratio should be between 30:1 and 10:1 (raw garbage
has 22-27:1). The volatile solids percent (VS) represent the portion of the matter
being anaerobically
decomposed.
In the biogas plant, 0.25-0.70m3 biogas per kg volatile solids is produced.
The loading rate should be in the range of1-1.5 kg volatile solids/ m3
digester/day.
the pH should be between 7 and 7.4 and the dilution with water 1:1. (Veziroglu,
1991)
The retention time for mesophilic digestion should be 30-60 days (Werner et al,
1989).
Anaerobic decomposition is possible at three temperature ranges: psychrophilic
(
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Structure Of Bio-Gas Plant
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Graphical representation of retention
time v/s total gas produced.
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Economics
Wastage of food in NMIMSNumber of students staying in hostel - 1000 (approx.)
Wastage of food per head per day - 200 gms(approx.)
Therefore wastage of food by 1000
students per day
= 1000*0.200
= 200 kgs
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Savings at NMIMS
ELECTRICITY Production of bio-gas per kg - 0.5m3(from 0.3m3-0.7m3)
1m3 biogas = 5200-5900 kcal of heat energy
= 1.25 kwh electricityHence we get
0.625 kwh per kg food waste
Hence,
0.625kwh*200kgs = 125kwh per day Hence we can produce 125 kwh electricity
per day
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Benefits
Bio-Gas production has many benefits as a form ofrenewable energy production , sustainable wastemanagement & fertilizer production.
In addition it is a closed loop system.
Qualities of sludge get significantly improve since theodor gets reduced and weed seeds and pathogens getremoved.
All together biogas production contributes to sustainable
development.
Helps reduce the CO2 emission and thereby to reachgoals set by the kyoto protocol.
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Fund Source
To implement biogas electricity generation
plant money will be provided by the university
charitable trust or from the bank.