STUDY ON BIO-METHANATION USING POULTRY DROPPING-Abdullah Nasir Pulak

ISSN 2224-1698 Jagannath University Journal of Science, Volume-2, Number-II, July 2013
1
STUDYONBIO-METHANATIONUSINGPOULTRYDROPPING
WITHCOWDUNG
*
A. N. Pulak1
, A. K. M. Lutfor Rahman1
, M.A. Rouf 2
, M.S. Islam2
, T. Rabeya2
, A. Samad1
and M. A. Mamun1
1
Department of Chemistry, Jagannath University, Dhaka, Bangladesh
2
Institute of Fuel Research and Development, BCSIR, Dr. Qudrat-I- Khuda Road
Dhanmondi, Dhaka-1205.
Abstract
Biogas generation from poultry dropping (contain 66.72% organic matter) in 2 litter batch reactor was
studied at 6% total solid (TS) concentration with or without mixing other substrate at room temperature.
Poultry dropping alone was found unsuitable as a substrate for biogas production under anaerobic
condition due to low Carbon Nitrogen (C/N) ratio. Therefore, cow dung was used as co-substrate in order
to increase the C/N ratio. Study was carried out using different proportion of cow dung and poultry
dropping in four different laboratory scale reactors (D1-D4) for 50 days digestion period. The volatile solid
destruction for D1-D4 reactors were 45%, 53%, 49% and 30% and methane contents 73.9%, 73.2%,
71.6% and 71.6%, respectively. Chemical Oxygen Demand (COD) reductions were found 45.19%, 54%,
49.16% and 30.03%, respectively. Reactor D2 gave the optimum results in terms of volatile solid (VS)
reduction (53%), specific gas yield (0.72 l/g) and methane content (73.2%).
Key words: Biomethanation, poultry droppings, poultry litter, cow dung, biogas.
1. Introduction
Improper or very often no management option is observed for a large amount of poultry solid
wastes in Bangladesh. Crude dumping of this waste is not only obnoxious but also unsafe for
the environment. Small and large-scale poultry farms are expanding rapidly which provide us
meat, eggs and employment. At the same time, it also produces large quantities of waste
materials in the open space. A report from Poultry Sector Development Project gives a figure of
112,000 commercial poultry farms, which together produces about 5,900 tons of litter daily
(Sinha and Rahman, 2005). Farms with less than 100 birds are not included in this estimation.
In many areas it is possible to dispose poultry manure by spreading it on cropland or grassland.
However, the amount of available land is not enough for spreading poultry manure. About 3.6
metric tons of fresh manure may be spread on 0.4 hector of land devoted for crop production.
Moreover, manure can be spread only in a particular time of the year that necessitates storage of
manure. The following schematic diagram shows the environmental impact of poultry waste
used in cooking.
Corresponding author: lrahman1973@gmail.com; Tel.: +8802 7176191; +8801732108451

A. N. Pulaket al.
2
Fig. 1: Environmental impacts of using poultry waste as cooking fuel.
Therefore, high demand stands for the management with proper use of poultry waste
(droppings). Biogas from the anaerobic digestion of cow dung has already been attracted as a
significant source of energy. Hence, poultry waste could be considered as an alternative source
of energy through the anaerobic digestion. Anaerobic digestion has two main end products:
biogas and digested materials (Seadi et. al., 2008). It ensures recovery of energy in the form of
biogas which is a clean fuel as compared to other solid or liquid one (Thangamani et al, 2009).
Digested material is the decomposed substrate, rich in macro and micro nutrients and therefore
suitable to be used as plant fertilizer (Seadi et. al., 2008). It occupies very little land and
requires low or no energy in operation (Rahman and Muyeed, 2010). Attempt has been taken
to evaluate biogas from poultry droppings mixed with cow dung and poultry litter. It is expected
that the information generated from this study will open a new source of bio energy to
compensate our crisis.
2. Material and Methods
The poultry droppings and litter were collected from the poultry farm located at Khalpar,
Joypara, Dohar, Dhaka. After cessation of gas production in cow dung based reactor, the
digested residue was used as inoculum for the present experiment. The composition of poultry
droppings, cow dung, poultry litter and inoculum used in the experiment described in Table 1.
Batch incubation digestion system was run in the present observation. Substrate containing
mixture of waste was transferred into 2-litre capacity wide mouth glass bottle (digester).
Different quantities of waste materials were mixed and added to the glass bottle to obtain an
initial volume of the substrate 1 liter in all the reactors. The digester was connected to a
calibrated measuring cylinder with water displacement arrangement to measure the volume of
biogas produced. It was placed in water bath throughout the duration of the experiment to
maintain a constant temperature of operation. The content of the digesters were rigorously
agitated intermittently at 4-day interval over the retention period of 20 days. Experimental set up
and sample collections are shown in Fig.2.

Jagannath University Journal of Science, Volume-2, Number-II, July 2013
3
Fig. 2: Experimental set up with sample collection.
Table 1: The ratio of different substrates in different reactors
Reactors
Name
Total
Solid
(%)
% of
Poultry
litter
(g)
% of
Poultry
dropping
(g)
% of
Cow
dung
(g)
Inoculums
(ml)
Tap
Water
(ml)
Vol. of
the
slurry
(ml)
D1
6
0 100 0 100 Amount
required to
be filled
up 1000ml
1000
D2 0 75 25 100
D3 0 50 50 100
D4 30 70 0 100
The total gas production was measured at an interval of 24 h. Contents of the glass bottle
were mixed manually after every gas measurement. The entire test was conducted at a
temperature of 30 ± 3o
C for a period of 8 weeks
Sample analysis
pH of the substrate solution was monitored regularly by using a glass electrode pH meter
(HANNA). From second week of the digestion start COD reduction was monitored using
standard K2Cr2O7. Steady-state condition is identified when the COD value of the effluent
and daily biogas production is measured to be the same for two or three consecutive days.
The COD/VS ratio of the 6% substrate was calculated from: Amount of methane
generated from 1gm VS degraded = Methane generated from reduction of 1g of COD ×
(i); i=COD/VS. The calculated values of i for reactor D1, D2, D3 and D4 were found 3.19,
2.54, 2.14 and 3.03, respectively.
Carbon and Nitrogen contents of the poultry droppings, poultry litter were determined by
a C-H-N elemental analyzer. Moisture and ash contents were estimated by drying at
1050
C and complete combustion at 8000
C, respectively. The protein content was
estimated from the nitrogen content by multiplying with 6.25[Rouf et al, 2010]. Total
solids (TS), Volatile solids (VS), and Volatile Fatty Acids (VFA) were estimated
according to the procedures recommended in the standard methods for examination of
water and waste water (APHA 1998). The total methane content present in the gas was
measured by alkali scrubbing method -a known quantity of gas drawn out using a sterile
syringe was injected back into a liquid displacement system containing strong potassium
hydroxide solution and the volume of methane gas present in biogas mixture was

A. N. Pulaket al.
4
determined by the volume of alkali displaced against the known quantity of biogas
injected.
3. Results and Discussion
Characterization of raw materials was done and is presented in Table 2. The
growth and catabolism of microbes need various kinds of nutrients, especially of carbon,
nitrogen and phosphorus. Besides the property of gas production of feedstock, it is
necessary to take the proper ratio of carbon and nitrogen (C/N) into account. Carbon is
utilized for energy and nitrogen for the building of the cell structure. A specific group of
microbes always consume these two elements in proportion. It is commonly recognized
that a C/N ratio of 20-30 : 1 is suitable (Rouf et al, 2010). The C/N ratio of poultry
droppings and litter is quite low for optimum biogas generation (Rouf et al, 2010) and
that low C/N value was increased by mixing with cow dung. Low C/N value substrate
when mixed with high C/N value substrate the slurry performs better (Rouf et al, 1999).
The domestic sewage would also act as a source of various micro organisms required for
anaerobic digestion (Tangamani et al, 2009).
Table 2: Characteristics of Substrates.
Constituents Poultry
Dropping
Poultry
litter
Cow dung Inoculum
pH 7.0 8.0 7.8 6.43
Ash content (%) based on TS 33.28
Moisture Content (%) 77.5 27.66 83 96
TS (%) 22.5 72.34 17 6
VS (%) based on TS 66.72 83.95 89 88.66
COD(g/l) 128 76.5 - -
C/N Ratio 6.5 7.5 24 -
Calorific Value (kcal/kg) 3980.75 4519.77 4658.07 -
Figure 3 (a) states the volumes of daily gas accumulation with varying the amount of
poultry droppings in different reactors. Belt shape trend of daily gas generation observes
in the reactor D1 (VS conc.40g/l), which contains 100% poultry droppings with 6% solid
of the slurry. It shows lower range of daily gas production (100-400ml in an average).
The gas production in the D1 started from the 4th
day after setting up the reactor. The first
peak gas observed 500ml on the 7th
day and second one 900ml on 38th
day of digestion
period. Quite frequent shape of the daily gas production observes in Fig. 2 (b) for D2 reactor
(VS conc. 43.35 g/l), which contains 75% poultry droppings and 25% cow dung. In this reactor
production of gas started from the third day after recharging it with the slurry. The peak gas
obtained 1850 ml on the 26th
day. The daily gas production in D3 reactor (VS conc. 46.7 g/l)

5
which contains 50% poultry droppings and 50% cow dung also started from the 3rd
day of
charging the digesters with the slurry.
The rate of gas generation gradually increases with the increase of the digestion period.
In this reactor, the first peak gas observed 450ml on 3rd
day and second one 800ml on the
18th
day. 70% poultry droppings with 30% poultry litter were mixed for D4 reactor (VS
conc. 43 g/l;). First peak gas found 500 ml on 3rd
day and second one 200 ml on the 8th
day in this reactor. It observes that gas production rate declines after 50th
days in all
cases. Comparing gas production amongst four reactors, D2 shows the highest peak
production of 1850 mL on the 26th
day which contain 75% poultry dropping with 25%
cow dung. Therefore, poultry dropping and cow dung at a ratio of 3:1 is favorable for bio
methanation. Initial peak at first day for every reactor is due to the air and CO2.
Cumulative gas production with time is shown in Fig. 4. The cumulative productions in
D1- D4 are 11.4L, 16.9L, 14.45L and 8.75L, respectively. After the lag period, the
cumulative volume of gas increased sharply and continued up to 50 days of fermentation.
It shows that the highest amount of gases produced in D2 digester. Therefore, 25% cow
dung is essential for bio-methanation of poultry dropping.
Fig. 4: Cumulative gas production in different reactors.
The initial and final values of volatile solid concentration and reduction in different reactors and
the yield of gas generation are shown in the Table 3.
Table 3: Change in volatile solid concentration in the reactors and yield constant of
different reactors.
Reactor
VS (g/l) VS reduction
(%)
Amount of
gas produced
(L)
Yield of gas
generation
(l/g)
Initial Final
D1 40 22 45 11.4 0.64
D2 43.35 20 53 16.9 0.72
D3 46.7 23.8 49 14.45 0.63
D4 43 30 30 8.75 0.67

A. N. Pulaket al.
6
The percentage of volatile solid destruction in D1 and D4 reactor (which contain 100% poultry
dropping and 70% poultry dropping with 30% poultry litter, respectively) is lower than other
reactors. As there was no cow dung in reactor D1 and D4 to speed up the process with bacteria,
therefore, VS reduction is lower. On the other hand in D2 reactor, volatile solids reduction
achieved 53%, where 25% cow dung was used as co-substrate. Although percentage of VS
reduction little lower in D3 reactor but gas production is comparable to D2. From the above
discussion it can be said that VS reduction rate not only depends on initial concentration but
also on the types of volatile matter in the slurry. The gas yield found highest in D2 reactor than
the other three reactors. The results draw the attention that poultry dropping alone is not suitable
enough for optimum gas generation.
Effect of Cow dung
The variations in volume of gas production with different percentages of cow dung used in the
slurry of different reactors are given in Fig. 5. In the total solids of slurry, a certain amount of
cow dung used for initial gas generation, buffering media and seeding material. There is no cow
dung in D1 reactor and therefore, lag time is 4 days before the onset of minimum gas generation
start. More time was required due to digest the poultry dropping in the absence of cow dung. On
the other hand, poultry litter is used with poultry dropping as VS(in D4 reactor), comparatively
less amount of gas obtained and only 30% of VS was degraded. This is due to the low C/N ratio
of both the substrates. From the performance of four reactors, it can be concluded that optimum
gas generation takes place when 25% of total solids of the slurry in a reactor is cow dung.
Fig. 5: Effect of cow dung on gas production.
COD Value reduction
Chemical oxygen demand (COD) of the slurry considerably reduced with anaerobic digestion
process. The reduction of COD value means the reduction of pollution from substrate through
the anaerobic treatment process. The COD value curves for four different reactors are shown in
Fig.6. The trend line shows that good correlation exists between digestion time and COD value
reduction for all reactors.

7
Fig. 6: Trend curve for COD value for different reactors.
For D1, D2, D3 and D4 reactors, COD reduction rate observed 45.19%, 54%, 49.16% and
30.03%, respectively. Maximum COD reduction achieved from reactor D2 where the maximum
gas is produced. COD reduction value is comparable with the reference value given by Rahman
and Muyeed (2010). The amount of methane generated from conversion of a unit mass of a
substrate depends on the composition of the feed materials.
Effect of temperature
The digestion period was 50 days from May to June in this study. The climate was hot and dry
in this period and there was no special arrangement to maintain the optimum temperature (35o
C). For gas generation, the room temperature prevailed 30±6 o
C during the digestion period (
Bosu, 1998). It was found that the gas production increased with temperature. This confirms the
dependency of biogas generation on temperature. According to Seadi (2001) gas generation
might be ceased due to the sudden drop of temperature.
Effect of pH
The pH is another important process monitoring parameter for anaerobic digestion. According
to Rahman and Muyeed (2010), the desirable pH range is 6.5-8.0 for anaerobic digestion
process and the highest gas yield was observed in the Chengdu Research Institute was 7.5 to
8.0. Figure 7 shows the pH profile for the D2 reactor with pH range of 7.2 to 7.5. Initially pH
levels of the slurry reduced because of the production of organic acid. The acid former bacteria
active in this stage and substrate converted to acid quickly. As a result pH decreased. After that,
methanogenic bacteria starts its work. The volatile acid converted to methane, carbon dioxide
and consequently pH increased again. The following reactions might be taken place in the test
reactor:

A. N. Pulaket al.
8
Hydrolysis Acetogenic bacteria
Cellulose → C6H12O6 → 2CH3COOH (acetic acid) + 2CO2 + 4H2 (1)
Methanogenic bacteria
CH3COOH (acetic acid) → CH4+CO2 (2)
CO2 + H2 → CH4 (3)
6.2
6.4
6.6
6.8
7.0
7.2
7.4
7.6
0 10 20 30 40 50
pH
DigestionPeriod, Days
Fig. 5 pH profile for D2 reactor
4. Conclusion
The poultry droppings contained 66.72 % biodegradable VS alone is not a suitable substrate for
anaerobic digestion due to its low C/N ratio. Addition of cow dung with poultry droppings was
found to enhance biogas production. Cow dung increases the C/N ratio and helps the poultry
droppings to keep pH scale close to 7. Among all the compositions experimented 25% cow
dung was found favorable with poultry dropping and gave the optimum results in terms of
volatile solid (VS) reduction (53%), specific gas yield (0.72 l/g) and methane yield (73.2%).
From the process of bio-methanation of poultry droppings, we can get clean fuel, organic good
quality fertilizer and hygienic environment. Improper management of poultry waste (dropping)
contributes to a significant amount of pollution to our environment. Therefore, it is of high time
to consider this issue seriously. Energy is required in our everyday life as well as for the
industry. Hence, recovery of energy from the poultry solid waste by anaerobic digestion might
be a sustainable and environment friendly option for poultry waste management.
References
APHA 1998. Standard methods for the examination of water and wastewater : American
Public Health Association, Washington DC.
Bosu, S. K. 1998. Effect of Mechanical mixing and dung concentration on biogas generation:
M.Sc. Engg. Thesis, Dept. of Civil Engg. BUET, Dhaka, Bangladesh.

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Rouf, M. A, Bajpai, P. K., and Jotshi. C.K. 1999. Characterization of press mud from sugar
industry and its potential for biogas generation. Proc.CHEMCON-99 (Indian chemical
engineering congress), Chanigarh, December 20-23, pap.RMA-158.
Rouf, M. A; Bajpai, P. K., and Jotshi, C.K. 2010. Optimization of Biogas generation from
press mud in batch reactor. Bangladesh j.Sci. Ind.Res. 45(4): 371-376.
Rahman, M.H. and Al-Muyeed, A. 2010. Solid and Hazardous waste management. Published
by ITN-BUET, Dhaka, Bangladesh, first edition: 179-214.
Sinha H. M. and Rahman M M, 2005 . Environmental Management Practices of Poultry Waste
: published by Bangladesh Poultry Sector Development Project.
Al Seadi T., Rutz D., Prassl H., Köttner M., Finsterwalder T., Volk S., Janssen R. (2008);
“Biogas Handbook.”; ISBN 978-87-992962-0-0; Published by University of Southern
Denmark Esbjerg, Niels Bohrs Vej 9-10, DK-6700 Esbjerg, Denmark,
http://www.sdu.dk.
Seadi Al T. 2001. Good practice in quality management of AD residues from biogas
production, Report made for the International Energy Agency, Task 24-Energy from Biological
Conversion of Organic Waste, Published by IEA Bioenergy and AEA Technology
Environment, Oxfordshire, United Kingdom.
Thangamani, A., Rajakumar, S. and Ramanujam, R. A. 2009. Anaerobic Co-digestion of
hazardous tannery solid waste and primary sludge: biodegradation kinetics and metabolite
analysis : Clean Techn. Environ Policy, Springer.

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