Bio Gas Plant by Kitchen waste

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RECYCLING OF KITCHEN WASTE
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MAIN AIM

• BIOGAS PRODUCTION
• AND
• SLUDGE AS MANURE

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• USES OF BIOGAS
• Biogas can replace LPG to some extent.(Can be
  supplied to hostel kitchens)
• It can be used as fuel in running machines like
  vehicles
• It can be used to produce electricity.
• The digested sludge is used as manure directly.
• ADVANTAGES OF BIOGAS
• It causes no environmental effects .
• There is no loss of mass.
• It is cheaper and affordable.

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What is BIOGAS?

• BIOGAS is a mixture of gases which are produced
  due to anaerobic fermentation of any organic
  matter.
• The typical mixture of gases contains -

Gas Percentage
Methane 50 70
Carbon Dioxide 25 50
Hydrogen 0 - 1
Nitrogen 0 - 10
Hydrogen Sulfide 0 - 3
Oxygen 0 - 0.5
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Where does BIOGAS come from?

• Biogas can be produced from any raw materials
  like
• Agriculture waste
• Manure
• Municipal Waste
• Plant Material
• Sewage
• FOOD WASTE or GREEN WASTE
• In this project we use only food waste from our
  Hostel Kitchen.

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Who Produce BIOGAS?

• BIOGAS production is a COMPLEX process which
  include several kinds of MICROORGANISMS.
• Bacteria
• Fungi
• The complete process is more of a symbiosis
  between many microorganisms.
• In this project we use only BACTERIA.

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FUNGI

• It produces BIOGAS mainly from materials
  containing high LIGNOCELLULOSE.
• Fungi can produce Biogas from food waste but the
  yeild is very low which is uneconomical.

SUBSTRATE LIGNIN CONTENT FUNGI
Wheat Straw 16 21 Neocallimastix frontalis
Rice Straw 18 Pyromyces M014
Hard Wood 18 25 Neocallimastix sp.
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BACTERIA

• Four types of bacteria are used in BIOGAS
  production.
• They are-

TYPE EXAMPLES
Hydrolytic Bacteria Bacillus,Cellulomonas, Eubacterium
Acedogenic Bacteria Propionibacterium, Butyrivibrio,Acetovibrio
Acetogenic Bacteria Clostridia,Acetovibrio
Methanogenic Bacteria Methanococcus, Methanobacterium
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How BACTERIA produce BIOGAS?
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ENHANCEMENT IN YIELD

• Introducing H2 Producing Bacteria
  (Bioaugmentation)
• In the overall process, conversion of H2 and CO2
  to methane(CH4) is the rate limiting step.
• Co2 H2 methanogenotropic bacteria
  CH4
• From the studies, it is evident that production
  of high H2 leads to production of high CH4
• From the study done by K.L.Kovax et.al, the H2
  producing bacteria enhanced the production of
  BIOGAS.

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• Two Bacteria were used in the experiment but, we
  use only mesophilic bacteria (Enterobacter
  cloacae)
• Because, It grows in normal temperature and no
  external heat is required.
• Initially the bacteria is cultured in the lab and
  then it should be added in the substrate i.e
  fermentor
• As it is a anaerobic bacteria it is very easy for
  bacteria to grow in the biogas fermentor.

BACTERIA NAME TYPE
Enterobacter cloacae Mesophilic
Caldicellulosiruptor saccharolyticus Thermophilic
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• Where can we get these Bacteria
• There are many laboratories which sell bacteria.
  NATIONAL CHEMICAL LABORATORIES (NCL),PUNE is one
  of the best laboratories which sell Enterobacter
  cloacae.
• They cost Rs.3000 per culture.
• The purchased strain is further cultured in the
  laboratory and then immobilized.
• The immobilization of the strain is achieved by
  Polytetraflouroethylene (PTFE) Membranes.

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• Problems associated with H2 production -
• High H2 Production - Due to high production of
  H2,there is a chance of decreased production of
  methane.
• Presence of high H2 causes popping sound when
  burning.
• Low H2 production- 30 of methane is produced
  from conversion of CO2 and H2. Low H2 may
  decrease this amount even less.
• To overcome these problems we are
  going for IMMOBILIZATION OF BACTERIA.

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FERMENTOR MODEL

• Two stage fermentor is ideal for the higher yield
  of biogas.
• It reduces the Hydraulic Retention Time (HRT)
• HRT is the total time that
  substrate spends in the fermentor.
• MIXING MECHANISM-
• First Stage- It includes Hydrolysis and
  Acidogenesis.The fermented slurry is recirculated
  through pump.
• Second Stage-It includes acetogenesis and
  methanogenesis. The gas from this stage is
  compressed and resent to the same fermentor from
  bottom.This helps in mixing the slurry.

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Working Mechanism

• COLLECTION OF WASTE
• On an average 150-200 kg of food waste comes from
  every boys hostel and 100-120 kg of food waste
  comes from every girls hostel.
• From calculations it is found that 1500-2000 kg
  waste comes from 7 boys hostels and 6 girls
  hostel.
• These are collected in big plastic drums.
• SEGGREGATION
• Since the collected waste is from kitchens there
  are very less chances of mixing of unwanted
  wastes like plastic and Aluminum foils.

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• Contd..
• Incase of plastic and other waste manual
  separation is done itself in the mess by
  allotting separate bins for them.
• CRUSHING
• A 5HP motor is used for crushing which runs by 10
  panel solar unit.
• MIXING
• Mixing is done in a separate tank in which
  impellors run by common motor that is used for
  crushing.

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• STAGE ONE
• Stage one is an underground fixed dome shaped
  fermentor.
• For the start up of the fermentor, an activated
  microbial slurry from nearby biogas plant should
  be taken and cultured for 15 20 days because
  already working biogas plant contains most
  effective bacterial consortia.
• Along with this bacteria,the suspended
  Enterobacter cloacae membrane is fixed in the
  fermentor for more H2 production.
• After the culture is done,the premixed slurry is
  added into the fermentor for initial
  fermentation.
• The HRT is 3o days in which hydrolysis and
  acidogenesis is done.
• Mixing is done by slurry recirculation by 10 HP
  drive pump.

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• STAGE TWO
• It is an underground floating drum type
  fermentor.
• For the startup the same process is done as in
  first stage.
• The initially digested slurry is transferred into
  the fermentor through a pipe by gravity (as the
  fermentors are held in different heights).
• Acetogenesis and Methenogenesis are done in this
  stage.
• The mixing is done by recirculating the formed
  gas.
• The fully fermented sludge is drived out of the
  fermentor through the opening present at the
  bottom.

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GAS PURIFICATION

• WATER
  SCRUBBING
• Carbon dioxide is soluble in water.
• Water scrubbing uses the higher solubility of
  CO2 in water to separate the CO2 from biogas.
•  This process is done under high pressure and
  removes H2S as well as CO2.
• The main disadvantage of this process is that it
  requires a large volume of water that must be
  purified and recycled.

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Analysis

• Analysis on biogas production
• A typical study says that 1 KG of Kitchen waste
  produces 0.75 m3 of biogas
• Therefore,2000 kg waste gives
• 2000 0.75 1500 m3.
• Analysis on LPG usage
• On an average 100 of 14.2 kg LPG cylinders are
  used in the Hostels.
• The density of LPG is 1.85 m3.
• Therefore,100 cylinders of LPG contains 766 m3 of
  gas.

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COMPARISION

• METHANE

• LPG

• Calorific value of methane is 38.7 MJ/m3
• Therefore ,total energy from 1500m3 is equal to
  58050 MJ
• This is the one time investment and Just
  maintenance costs

• Calorific value of LPG is 93.2 MJ/m3
• The total energy from 766 m3 is equal to 71391 MJ
• As per now, the cost for 100 cylinders exceeds
  RS 70,000 and this is a daily investment

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• PERCENTAGE SAVING OF LPG
• Total LPG saved per day (58050/71391)100
• 
  81.13
• Therefore it is evident that the biogas can be
  used as alternative substitute for fossil fuels.

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BIO GAS PLANT VISIT AT HISAR, HARYANA
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THANK YOU ANY QUESTIONS????