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8/10/2019 Production of BioGas Using Kitchen Waste
http://slidepdf.com/reader/full/production-of-biogas-using-kitchen-waste 1/6
www.ijesci.org International Journal of Energy Science (IJES) Volume 3 Issue 6, December 2013
doi: 10.14355/ijes.2013.0306.05
408
The Production of Biogas Using Kitchen
Waste Ravi P. Agrahari1 , G. N. Tiwari2
1,2Centre for Energy Studies, IIT Delhi,
Hauz khas, New Delhi, India‐110016
[email protected]; [email protected]
Abstract
Kitchen waste is the best alternative for biogas production in
a community level biogas plant. It is produced when
bacteria degrade organic matter in the absence of air. Biogas
contains around 55‐65% of methane, 30‐40% of carbon
dioxide. The calorific value of biogas is appreciably high (around 4700 kcal or 20 MJ at around 55% methane content).
The gas can effectively be utilized for generation of power
through a biogas based power‐generation system after
dewatering and cleaning of the gas. In addition, the slurry
produced in the process provides valuable organic manure
for farming and sustaining the soil fertility. In this paper, an
attempt has been made to test the performance of different
ratio of kitchen waste in a metal made portable floating type
biogas plant of volume capacity 0.018 m3 for outdoor
climatic condition of New Delhi, India . Each of the biogas
plant 30 Kg slurry capacity in batch system for all
measurement.
During these period, the temperature, solar radiation and
relative humidity have been measured. We have also
analysed the constituent of biogas, pH, volume and rate of
biogas production at different level of temperature
observation on daily basis. Here we also compare the rate of
biogas production from kitchen waste with the other energy
sources used for cooking purposes like LPG, Kerosene and
Coal.
Keywords
Digester; Slurry; Kitchen Waste; Batch System; Organic Manure
Introduction
Biogas is produced from organic wastes by concerned
action of various group of anaerobic bacteria through
anaerobic decomposition. Anaerobic decomposition is
a two‐stage process as specific bacteria fed on certain
organic materials. In the first stage, acidic bacteria
dismantle the complex organic molecules into
peptides, glycerol, alcohol and the simpler sugars.
When these compounds have been produced in
sufficient
quantities,
a
second
type
of
bacteria
starts
to
convert these simpler compounds into methane. These
methane producing bacteria are particularly
influenced by the ambient conditions, which can slow
or halt the process completely. Globally, the reduction
of green house gas emissions particularly CO2 has
become more important. Currently much of the carbon
dioxide emitted to the atmosphere is the result of
anthropogenic activities from the use of the fossil fuel in the transportation and energy sectors. Significant
emission reductions may be achieved in the energy
sector by improving efficiency through the use of
alternative fuels. Through the use of biogas plant we
can save the CO2 emission in the atmosphere.
The performance of a greenhouse integrated biogas
plant was analysed with their basic aim to reduce
thermal loss to ambient in harsh cold climates (Usmani
JA et al 1996). Due to the lower temperature, biogas
production decreases drastically and may stop. Thus,
to enhance biogas production, a higher digester
temperature than ambient temperature is required.
The green house concept should be integrated for
larger capacity biogas plant (Lau AK et al 1987). It has
been suggested that the rate of biogas production and
the period to achieve the optimum temperature are
function of the temperature of the slurry. Also, for a
required production rate of biogas, the period to
achieve the optimum temperature should be reduced
(Tiwari GN et al 1988; Tiwari GN et al 1986). A heat
exchanger connected to a flat plate collector has been
suggested for heating of the slurry (Tiwari GN et al
1992). Installation of PVC greenhouse type structure
over a biogas plant allow solar heating of the substrate
from 18 °C to about 37 °C (Gupta RA et al 1988; Sodha
MS et al 1987; Sodha MS et al 1989 and Tiwari GN et al
1997). Solar greenhouse assisted biogas plant in hilly
region recommended and it has come to conclusion
that biogas‐green house hybrid system may be
successful in hilly regions where average temperature
remains below 37°C throughout the year (Vinoth KK
et
al
2008).
It
can
also
evaluate
the
carbon
credits
earned by energy security in India and also analyse
the return on capital for biogas plants with and
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www.ijesci.org International Journal of Energy Science (IJES) Volume 3 Issue 6, December 2013
410
temperature, relative humidity, and solar intensity
have been measured during this experiment. Gas
production have been recorded on daily basis by the
observation of upliftment height of dome. This
upliftment height is multiplied by 2πr and the volume
of biogas production is measured every day. This biogas sample has been taken out with the help of
toddler bags, which is safe to carry biogas without any
leakage and entry of atmospheric air, which has been
tested through gas chromatography.
Methodology And Experimental Observation
Different parameters like solar intensity, ambient
temperature, slurry temperature and average
humidity are measured on daily basis. These data
have been taken at the interval of 4:00 hours between
9:00 am to 5:00 pm due to presence of solar radiation.
Three readings have been taken in every day at 9:00
am, 1:00 pm and 5:00 pm. Here we use various ratio of
kitchen waste with water composition. Under the
analysis we have calculated the average of solar
intensity and relative humidity at these three different
times in a day until the biogas production inside the
biogas chamber stop. In this manner we have also
calculated the average ambient temperature and
average slurry temperature to find the different result
and observation. The production rate and methane
fraction have also been observed under the influence
of various temperature ranges during the
experimental work in New Delhi, India.
Result and Discussion
In this observation, all the research analysis has been
done under batch system. In the batch system, the
slurry has been added once to the digester for whole
duration of the process. It has been observed that the
production of biogas is dependent upon the
temperature and the solar intensity of the atmosphere
in aluminium made biogas plant. In these all the data
we got various analysis through various comparison.
Comparison among Various Ratio of Kitchen Waste
in Aluminium Made Biogas Plant
Kitchen waste can be useful under community level
biogas programme, where we can save LPG for
cooking purposes. This analysis has been done under
30 days (1 month) observation between September 23,
2011 to October 22, 2011 under aluminium made
biogas
plant.
In
this
observation,
we
have
taken
different ratio of kitchen waste and water with fixed
amount of inoculum. Inoculum is the anaerobically
digested slurry and contains anaerobic bacteria which
are responsible for biogas production. These kitchen
waste and water are in the ratio of 1:3(Case‐ A), 1:2
(Case‐ B), 1:1.4(Case‐ C) and 1:1(Case‐ D) with fixed
amount of inoculums (Table 2).
TABLE 2. : COMPARISON AMONG VARIOUS RATIO OF KITCHEN WASTE
UNDER BIOGAS PRODUCTION
Characters
Case‐
A6
kg(1:3
)
Case‐
B8
kg(1:2)
Case‐
C10 kg
(1:1.4)
Case‐
D12
kg(1:1)
Amount of kitchen
waste 6 kg 8 kg 10 kg 12 kg
Water 18 lt 16 lt 14 lt 12 lt
Inoculum 6 lt 6 lt 6 lt 6 lt
Ratio of kitchen
waste and water 1:3 1:2 1:1.4 1:1
pH 7.3 7.4 7.7 7.9
Total biogas
production (m3)
0.2184
6
0.2581
57 0.12785 0.12168
Maximum
methane fraction 42% 48% 44% No
Duration of
methane fraction
production in days
3‐11 3‐15 18‐22 No
Number of days
methane fraction
present
10 15 5 No
FIG 3 : VARIATION OF AVERAGE SLURRY TEMPERATURE ON
DAILY BASIS UNDER VARIOUS RATIO OF KITCHEN WASTE
Solar radiation is responsible for increasing the slurry
temperature inside the digester, which influences the
rate of biogas production. Average slurry temperature,
biogas production (volume) and methane fraction are
measured on daily basis in different ratio of kitchen
waste (Fig 3,4 and 5). By daily observation we got the
best result in case‐B of kitchen waste and water, where
we have used 8 kg kitchen waste, 16 liter water and 6
kg inoculum under biogas production. In case‐ A and
Case‐
B
we
obtained
the
good
result
but
in
the
case
of
case‐ C and case‐ D the biogas production was not
present. Even in the case of case‐ C the production of
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International Journal of Energy Science (IJES) Volume 3 Issue 6, December 2013 www.ijesci.org
411
biogas started from 18th days. Because earlier the pH
value was comparatively higher, which was not better
for the growth and activity of anaerobic bacteria but
after 17 days it became favorable due to some
microbial activity. In the case of case‐ D the pH value
was very high at which the bacterial activity was arrested so there was no production of biogas in this
ratio.
FIGURE 4. : VOLUME OF BIOGAS PRODUCTION IN RESPECT OF
NUMBER OF DAYS UNDER VARIOUS RATIO OF KITCHEN
WASTE
FIG 5. : MEASUREMENT OF METHANE FRACTION ON DAILY
BASIS UNDER VARIOUS RATIO OF KITCHEN WASTE
The synthesis of gas has been started from the first day
of the slurry feeding inside the biogas chamber under
case‐ A and case‐ B but we obtained methane fraction
from third day. Kitchen waste is rapidly disintegrated
by microorganism so the production of biogas stops
after 11th day and 12th days in the case of case‐ A and
case‐ B. The amount of biogas production is 0.218461
and 0.258157 m3 under case‐ A and case‐ B. The
retention period of biogas production is maximum 15
days in the case of kitchen waste. We have seen a best
utilization
of
kitchen
waste
from
ARTI
biogas
plant,
Erandwana, Pune, Maharashtra (India) under
continuous feeding, used for cooking purposes in
place of LPG (Table 3).
TABLE 3 : BIOGAS PRODUCTION FROM KITCHEN WASTE IN ARTI BIOGAS
PLANT IN TWO DIFFERENT SIZES
Characters Bigger size biogas
plant
Smaller size biogas
plant
Size 1 m3 digester 0.5 m3 digester
Capacity
upto 2 kg kitchen
waste
upto 1 kg kitchen
waste
Quantity of
gas
produced
upto 1 kg biogas,
capable of replacing
250 gm of LPG.
upto 0.5 kg biogas,
capable of replacing
100 gm of LPG.
Uses under
cooking
purposes
either breakfast or
one meal can be
cooked entirely on
biogas.
about 15‐20 min of
cooking (tea, snakes,
etc.) can be done.
Source: ARTI biogas plant, Flat No. 6, Ekta park Co‐op Hsg. Soc.,
Behind Nirmitee Showroom, Law College Road, Erandwana, Pune,
Maharashtra (India)‐ 411004
Production of Energy (Heat, Light, Electricity)
The calorific value of biogas is about 6 kWh/ m3. which
is equal to about half a liter of diesel oil. The net
calorific value of fuel also depends on the efficiency of
the burners or appliances. Methane is the main
important component under the aspect of using biogas
as a fuel. The use of biogas can replace various
conventional fuel like kerosene or firewood and
protect the environment. Biogas is the best substitute
of firewood in rural households. The biogas generated
from small and medium sized units (up to 6 m3) is
generally used for cooking and lighting purposes. If
we use a 8 kg (1:2 ratio) [case‐ B] kitchen waste for
biogas production, we can save various fuel sources
which can be used as alternatives. Total biogas
production from 8 kg (1:2 ratio) kitchen waste of
volume capacity 0.018 m3 biogas plant was 0.258157
m3 during whole retention period. The amount of
other
fuel
sources
which
we
can
save
by
the
use
of
8
kg (1:2 ratio)[case‐B] kitchen waste in respect of ICAR
data (Table 4).
Women spend 2‐4 hours per day in searching and
carrying the firewood. Once a biogas is installed, they
will have much extra time for herself and her children.
This will help in improving their quality. They will get
more time for education and interesting activities
outside the home. Biogas plants also improve health
conditions in the homes. The annual time saving for
firewood collection and cooking average to almost
1000 hours in each household provided with a biogas
plant.
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413
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Ravi P. Agrahari MSc., is research scholar in
Centre for Energy Studies, IIT Delhi, New
Delhi, India. Mr. Agrahari was born on
December 2, 1981 at Gorakhpur (U.P.) in
India. Mr. Agrahari completed his Masters in
botany in 2002 from the Deen Dayal
Upadhyay Gorakhpur University, Gorakhpur, UP, India.
Then he cleared CSIR‐ JRF exam in june 2008 and joined as a
Research Scholar with Prof. G. N. Tiwari and Prof. M. S.
Sodha, Centre for Energy Studies, IIT Delhi, Hauz khas,
New Delhi, India. Mr. Agrahari also works as an
independent consultant in Bag Energy Research Society,
Varanasi, UP, India in the fields mof environment,
renewable and sustainable energy. His fields of interests
include environment and development, socio economic
impact assessment, sustainable energy and biogas issues.
Dr. Gopal Nath Tiwari was born on July 1,
1951 at Adarsh Nagar, Sagarpali, Ballia (U.P.)
in India. He has completed his M.Sc. (Physics)
and Ph.D in 1972 and 1976 from Banaras
Hindu University, Varanasi (U.P.), India. He is
recipient of JRF, SRF and PDF from CSIR,
Govt. of India during 1972‐1978. He joined as a Research
Associate at I.I.T. Delhi, New Delhi in 1978. He holds a
position of Professor at Centre of Energy Studies, I.I.T. Delhi,
New Delhi since 1997. He was energy expert in University of
Papua New Gunea, Port Morshy, PNG during 1987‐89. Dr.
Tiwari was visiting European Fellow at University of Ulster,
Northern Ireland (UK) during 1993 for six months. He has
visited many other countries namely Canada, USA, Italy,
Australia for short terms as an energy expert. He is recipient of National Hari Om Ashram Prerit S.S. Bhatnagar Award in
1982 for his seminal contribution in the field of solar
distillation. Dr. Tiwari has published to his credit more than
four hundred research papers in different National and
International Journals and author of eight text and reference
books on solar energy, greenhouse, passive heating/cooling,
Renewable Energy Resources etc. He has been nominated for
International IDEA Award for his work on solar distillation
in 1992.
Dr. Tiwari has supervised more than sixty Ph.D students in
various research areas of interest. His current areas of
research interest are Solar Energy and its applications in solar distillation, passive heating/cooling of building,
controlled environment greenhouse, aquaculture, water/air
heating system, crop production and drying, renewable
energy resources, energy analysis of all systems, techno‐
economic analysis, hybrid PV/thermal systems, clean
environment and rural energy etc.