International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
Bio-Gas Generation From Solid Waste
S.Karapagavalli, S.Suganya
DEPARTMENT OF CIVIL ENGINEERING
BHARATH UINVERSITY, CHENNAI 73
ABSTRACT
Biogas makes an important contribution to conserve the energy without
causing much load on the natural resources. Biogas is an important form of non
conventional renewable source of energy, which can be produced by the
degradation of organic waste. Vegetable market wastes which are generally
organic in nature can produce biogas when they are treated anaerobically. The
primary goal of our project is to utilize the market waste effectively by converting
the waste into bio gas. The tests were conducted to obtain the efficiency of gas
production and to know the different parameters affecting it.
ISSN: 2231-5381
http://www.ijettjournal.org
Page 44
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
1. INTRODUCTION
Biogas typically refers to a gas produced by the biological breakdown
of organic matter in the absence of oxygen. Biogas originates from biogenic
material and is a type of biofuel. One type of biogas is produced by anaerobic
digestion or fermentation of biodegradable materials such as biomass, manure or
sewage, municipal waste, and energy crops. This type of biogas is comprised
primarily of methane and carbon dioxide. The other principle type of biogas is
wood gas which is created by gasification of wood or other biomass. This type of
biogas is comprised primarily of nitrogen, hydrogen, and carbon monoxide, with
trace amounts of methane.
The gases methane, hydrogen and carbon monoxide can be combusted
or oxidized with oxygen. Air contains 21% oxygen. This energy release allows
biogas to be used as a fuel. Biogas can be used as a low-cost fuel in any country for
any heating purpose, such as cooking. It can also be utilized in modern waste
management facilities where it can be used to run any type of heat engine, to
generate either mechanical or electrical power. Biogas is a renewable fuel and
electricity produced from it can be used to attract renewable energy subsidies in
some parts of the world.
Vegetable market waste is one of the constituents of the solid waste
that creates aesthetically bad appearance in the areas of dumping. So this vegetable
market waste should also be managed. Lots of research is going for the
management of other solid wastes but this vegetable waste is not taken care. These
market wastes putrefy and create bad odour in the surrounding area and also help
in the growth of disease causing vectors such as mosquitoes etc., flies which cause
diseases to the human beings. The market waste has large amount of organic
content which can be used effectively for the production of energy, rich Bio gas by
ISSN: 2231-5381
http://www.ijettjournal.org
Page 45
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
the process called anaerobic digestion. This process is known as bio methanation.
In order to implement the process for the production of biogas experimental study
is necessary. These experiments will give an idea of what will be the output if the
plants are set up.
An acceptable pH, by itself, does not provide assurance that the digester will
work properly. In the event that rapid production of excess acids occurs through
the slug loading of a waste (e.g., loading of large volumes of material in one single
batch), the methane-formers may not reproduce fast enough to utilize the volatile
acids being produced. Rapid changes in pH can be moderated if the digester liquid
contains enough buffering capacity. Once the system has become well buffered, it
should be possible to add the organic material for which it was designed on a
regular basis with good results.
2. EXPERIMENTAL PROGRAMME
2.1 MATERIAL/SAMPLE COLLECTION:
The vegetable market waste require for the study has been collected from the
vegetable market, Perundurai. This waste is washed and crushed well to extract
liquid out of it. The vegetable waste such as tomatoes, beet root, radish, carrots,
leafy vegetables etc., is washed well before crushing. The waste fruits are also
collected and washed well. They are together then weighed using the weigh
balance. The crushing of the materials is done by mixer. The crushed mix is taken
as the feed essence for the micro organisms present in the waste water.
ISSN: 2231-5381
http://www.ijettjournal.org
Page 46
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
2.2 PREPARATION OF THE INNOCULUM
The sludge was taken from the Gobar-gas plant situated in Perundurai and
its characteristics were studied. To develop anaerobic micro organisms, the
collected sludge was kept in an air tight container for three weeks. By adding sugar
solution as feed for anaerobic micro organisms, innoculum is thus prepared and is
used in this experimental study.
2.3 SEWAGE CHARECTERISTICS
Tests conducted for determining the chemical characteristics of sewage help
in indicating: the stage of sewage decomposition, its strength, and extent and type
of treatment required for making it safe to the point of disposal. Chemical analysis
is, therefore, carried out on sewage which has been explained in subsequent
articles.
2.3.1 Total Solids:
Sewage normally contains very small amount of solids in relation to the
huge quantity of water (99.9%). It only contains about 0.05 to 0.1 percent (i.e.,)
500 to 1000 mg/l of total solids. Solids present in sewage may be in any of the four
forms: suspended solids, dissolved solids, colloidal solids, and settleable solids.
The total amount of solids present in a given sewage can be determined by
evaporating a known volume of sewage sample, and weighing the dry residue left.
The mass of the residue divided by the volume of the sample evaporated will
represent the total solids in mg/L, say S1. While suspended solids are those solids
which are retained by a filter of 1µm pores; and they are, therefore also called as
non filterable solids. The mass of the residue divided by weight of sample filtered
will represent the suspended solids, say S2, mg/L.
ISSN: 2231-5381
http://www.ijettjournal.org
Page 47
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
2.3.2 Volatile Solids:
The total suspended solids (S2) may either be volatile or fixed in order to
determine their proportion, the non filtered dry residue is burnt and ignited at about
550°C in an electric muffle furnace for about 15 to 20min. Loss of weight due to
ignition will represent the volatile solids say, S4 in , mg/L.
2.3.3 Fixed Solids
The difference between non filterable solids (S2) and volatile solids (S4) will
represent in the fixed solids.
2.3.4 pH Value
The pH value of sewage indicates the negative log of hydrogen ion
concentration present in sewage, the determination of pH value of sewage is
important, because of the fact that efficiency of certain treatment methods depends
upon the availability of a suitable pH value.
3. RESULTS AND DISCUSSIONS
Table 3.1 Initial characteristics for Sludge
Characteristics
Value
COD
600 mg/lit
pH
6.9
BOD
98.52 mg/L
Volatile Suspended Solids
4000 mg/lit
Suspended Solids
ISSN: 2231-5381
http://www.ijettjournal.org
5000 lit
Page 48
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
Table 3.2 Initial characteristics for Solid Waste
Characteristics
Value
COD
750 mg/lit
pH
6.8
BOD
73.89 mg/L
Mixed Liquor Volatile Suspended
Solids
1300 mg/L
Mixed Liquor Suspended Solids
3600 mg/L
Table 3.3 Values of pH and COD during stabilization period
Characteristics
Value
COD
600 mg/lit
pH
6.9
BOD
98.52 mg/L
Volatile Suspended Solids
4000 mg/lit
Suspended Solids
5000 mg/lit
ISSN: 2231-5381
http://www.ijettjournal.org
Page 49
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
Table 3.4 Values of pH and COD after feeding Solid waste
S.No.
Days
pH
1
2
3
4
5
6
7
1
2
3
4
5
6
7
6.8
6.8
6.9
6.9
6.9
7.0
6.9
COD in mg/lit
Inlet
Outlet
600
600
600
600
600
600
600
440
360
280
240
190
150
90
Table 3.5 COD Reduction
Date
14.02.08
16.02.08
18.02.08
20.02.08
22.02.08
24.02.08
26.02.08
28.02.08
01.03.08
03.03.08
05.03.08
07.03.08
ISSN: 2231-5381
COD Reduction
In %
37.85
39.85
45
54.28
60.39
66.78
72.03
76.52
80.26
84.5
87.39
89.42
http://www.ijettjournal.org
Page 50
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
100
90
80
70
60
50
40
30
20
10
0
COD Reduction %
14
.0
16 2 .0
.0 8
18 2 .0
.0 8
20 2 .0
.0 8
22 2 .0
.0 8
24 2 .0
.0 8
26 2 .0
.0 8
28 2 .0
.0 8
01 2 .0
.0 8
03 3 .0
.0 8
05 3 .0
.0 8
07 3 .0
.02 8
.0
8
% of COD Reduction
COD Reduction %
Date
Figure 3.1 Graph showing COD Reduction
ISSN: 2231-5381
http://www.ijettjournal.org
Page 51
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
Table 3.6 COD & Gas Generation
Burette Reading
Date
COD
Gas Generation
Blank Sample Difference
Ml
Ml
Ml
mg/lit
sec
lit/hr
8-Mar
24.5
20.1
4.4
440
1915
1.879896
9-Mar
24.6
21.4
3.2
360
1890
1.904762
10-Mar
25.2
22.7
2.5
280
1865
1.930295
11-Mar
25.5
23.2
2.3
240
1820
1.978022
12-Mar
25.1
23
2.1
190
1600
2.25
14-Mar
25.5
23.5
2
150
1580
2.278481
15-Mar
25.6
23.7
1.9
90
1560
2.307692
ISSN: 2231-5381
http://www.ijettjournal.org
Page 52
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
Table 3.7 Relation between COD & Gas Generation
Days
COD
mg/lit
Gas
Generation
Lit/hr
1
440
1.88
2
3
4
5
6
7
360
280
240
190
150
90
1.9
1.93
1.98
2.25
2.28
2.3
Fig 3.2 Graph showing relation between COD & Gas Generation
ISSN: 2231-5381
http://www.ijettjournal.org
Page 53
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
Table 4.8 Relation between Inlet and Outlet COD
Days
Inlet COD in mg/lit
Outlet COD in mg/lit
1
600
440
2
600
360
3
600
280
4
600
240
5
600
190
6
600
150
7
600
90
ISSN: 2231-5381
http://www.ijettjournal.org
Page 54
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
Relation between Inlet and Outlet COD
700
COD in mg/L
600
500
400
Inlet COD
300
Outlet COD
200
100
0
1
2
3
4
5
6
7
Days
Fig 3.3 Graph Showing relation between Inlet and Outlet COD
ISSN: 2231-5381
http://www.ijettjournal.org
Page 55
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
5. CONCLUSION
Vegetable market waste can be used for Biogas production so that we can
get revenue in the form of energy rich Biogas. Vegetable market waste is one of
the constituents of the solid waste that creates aesthetically bad appearance in the
areas of dumping. So this vegetable market waste should also be managed. The
vectors like Rodents, flies, Mosquitoes etc., can be reduced. The bio-gas obtained
by this method can be effectively used as a fuel. Using waste biomass to produce
energy can reduce the use of fossil fuels, reduce greenhouse gas emissions and
reduce pollution and waste management problems. One widespread use of Biofuel
is in home cooking and heating. Typical fuels for this are wood, charcoal or dried
dung. The Biofuel may be burned on an open fireplace or in a special stove.
ISSN: 2231-5381
http://www.ijettjournal.org
Page 56
International Journal of Engineering Trends and Technology (IJETT) – Volume3 Issue 4 Number1–Jul 2012
REFERENCE
1. “Biomethanation” for vegetable market waste at Chennai, from the
ministry of
Non Conventional Energy Resources.
2. “Management of Vegetable market waste” from “The journal of
Hazardous
Materials”.
3. McInerney, M. J. and Bryant, M. P., in “Fuel Gas Production from Biomass”,
West Palm Beach, Florida, 1981.
4. Studies on Biomethanation of vegetable market waste
Rajeshwari K V, Panth D C, Lata K, Kishore V V N. 1998
Biogas Forum III (74).
5. Metcalf, I.N.C. Eddy,Wastewater Engineering Treatment Disposal Reuse,
Tata Mcgraw-hill, New Delhi, 1996, ISBN 0-07-099461-7.
6. Standard methods for the examination of water and waste water edited by
Andrew D.Edton, Le Nore S.Clesceri, Arnold E.Greenberg, 19th edition 1995.
7. Manual non Municipal solid waste management (First Edition), constituted by
The Government Of India Ministry Urban Development.
ISSN: 2231-5381
http://www.ijettjournal.org
Page 57