Post on 14-Jul-2015
UTILIZATION OF DONKEY DUNG FOR BIOGAS PRODUCTION IN LAMU
COUNTY.
A RESEARCH PROPOSAL SUBMITED IN PARTIAL FULFILMENT FOR THE AWARD
OF A MASTERS OF SCIENCE IN LIVESTOCK SCIENCE (LIVESTOCK PRODUCTION
SYSTEMS) PWANI UNIVERSITY
BY
NAME: EMMANUEL MAE KARISA
CELL PHONE: 0721863812
REG. NO. A103/PU/2113/13
AUGUST 2014
Supervisors
1. Patterson Semenye
2. Dr Thomas Rewe
DECLERATION
This proposal is my original work and has not been presented for the award of a degree in any
University.
Signature_____________ Date: __________________
KARISA EMMANUEL MAE
Registration Number A103/PU/2113/13
Department of Animal Sciences
This proposal has been submitted for review with my approval as the University Supervisor.
Signature: _______________ Date: _____________
DR. PATTERSON SEMENYE
DEAN SCHOOL OF AGRICULTURE AND ENVIRONMENTAL SCIENCES.
This proposal has been submitted for review with my approval as the University
Supervisor. Signature: _______________ Date: _____________
DR THOMAS REWE
HEAD OF ANIMAL SCIENCE DEPARTMENT
SUMMARY
In recent years the prices of commercial energy sources have increased sharply and there is a
continuous depletion of these scarce resources. In developing countries the need for biomass
energy is not because biomass – based technologies can entirely resolve the nation’s difficulties
with escalating petroleum prices, but because of their urgency of their energy need. Properly
designed biomass conversion technologies could reduce the economic and environmental cost
for cooking and heating and in some cases provide opportunities for economic growth and
employment (Looher, 1984)
Energy is one of the prerequisites for growth of agriculture and industry. The energy
requirements met mainly through commercial energy sources like oil, natural gas etc. In recent
years the prices of these commercial energy sources have increased sharply and there is a
continuous depletion of these scarce resources. Hence there is an urgent need to develop and
exploit the alternative sources of energy.
Biogas is the fourth largest source of energy in the world supplying about 13 %( 55 EJ/YR),
which is equivalent to 25 million barrels of primary energy (Mittal, 1997)
There is therefore a need to study the productivity of biogas from donkey dung which is readily
available and a nuisance to the Lamu residents and also assess the different levels of mixing the
donkey dung with cow dung and biogas productivity.
Biogas from anaerobic digestion can be a solution to current and future energy
needs in Lamu. One option for improving biogas yield of anaerobic digestion of
Organic matter is co-digestion.
Cow dung and donkey manure will be co-digested together. The co-digested experiments were
conducted using flexi bio-digesters at Pwani university farm.
The volume of biogas produced will measured daily by a biogas flow meter.
The five treatments selected for the study will be:
• 25%donkey dung + 75% Cattle dung
• 50%donkey dung + 50% Cattle dung
• 75%donkey dung + 25% Cattle dung
• 100% donkey dung
• 100% cattle dung(control)
A flexi bag digester will be chosen for each substrate combination.
The investigation will be conducted in a completely Randomized Design (CRD) with three
replicates of each treatment.
INTRODUCTION
The world population of equines has been estimated at 44 million donkeys, 15 million mules,
and 65 million horses (Fielding & Pearson, 1991). Population figures for animals are notoriously
difficult to assemble, in many countries they are based on estimates and extrapolations.
However, even allowing for a 20 per cent margin of error, it is clear that these animals represent
a vast power resource (Sims & Kienzle, 2006). It is estimated that 80 per cent of the world’s
equine population, 90 million animals, are found in the developing world, including 97% of all
mules, 96% of donkeys, and 60% of horses (Pritchard et al., 2005; Wilson, 2002). Lamu is the
major island in Coastal Kenya that has the highest number of donkeys used as a means of
transport within the narrow roads in the town. There is a total of 1,832,519 donkey population in
Kenya, 31,916 in coast province and about 6000 in Lamu Island (Kenya National Bureau of
Statistics, 2009 census) .
More than half of the human population is dependent on the power provided by draft animals. A
study on the use of donkeys in Limuru (Kenya)IIII, where 43 per cent of households own
donkeys and an additional 20 per cent of households use them through a hiring scheme, indicated
that the use of donkey carts is an essential component of the farming system, In addition, in areas
where non-farm employment is becoming a critical factor in the economies of rural households,
donkeys are often owned for providing transport services (Njenga 1993). There are few
motorized vehicles on Lamu, only a couple of tractors, one ambulance and a handful
motorcycles. There is a clear consensus that more cars or motor vehicles are not desired on the
Island, among all groups such as farmers, employed by tourist industry, local governance and
tourists (Kombo, 2011). Instead of cars for overland transports there are donkeys, around 5000 of
them. Since they eat almost anything; fruit peels, other organic waste or corrugated paper (which
seem to be a favorite) they are actually part of the waste management of the island. The problem
is however not solved since the dung coming out the other end of the donkeys need to be taken
care of.
The main perceived environmental issue on Lamu, by both residents and tourists, is waste;
plastic bags, bottles and donkey dung, lying on the beach and other open surfaces.(Kombo,
2011), Dung, primarily available from donkeys, is not used today and ends up on the dumpsites.
It has value as organic fertilizer and an energy potential if used in Anaerobic Digestion to
produce biogas. Since there over 5000 donkeys on the island the volume of dung is substantial, if
each donkey produces two kilograms of dung per day the resource base would be over 3000 tons
per year. However, it is only realistic to make use of dung from the hard made streets of Lamu
Town and Shella. Infrastructure to collect donkey dung is already in place by Lamu Safi and
SERG. Daily around five 20 kg wheelbarrows of waste; dung mixed with sand and other waste,
are collected from Lamu Town and Shella.( Ali, Abdala, et al. 2012.)
Donkeys play a vital role in rural economies through the provision of draught power and
transport. Compared to other equids species, donkeys contribute the major proportion of readily
available transport needs of poor women and men living in hostile environments, enabling them
integrate into social and economic processes (Fernando and Starkey 1996). Donkeys are
preferred to other equine because of their affordability, survivability, docility and ease of training
and handling. The ability of donkeys to thrive on poor quality minimally supplemented feeds has
also made them popular in environments where feed shortages can seasonally become a critical
problem. Donkeys have been reported to survive better under drought condition than any
livestock species due to their small body size and low dry matter intake requirements minimizing
their water and maintenance needs in arid and semi-arid areas (NRC 1984).
Donkeys play a vital role in Lamu town residents economies through the provision of draught
power and transport compared to other regions in the country. With this increasing population
comes with a lot of waste from donkey dung littering the town posing health risk to the residents
for example the risk of infection with tetanus. Biogas is one of the good and promising source of
alternative energy. This energy can be harnessed successfully to meet the existing as well as
future needs of the rural areas. Biogas is the fourth largest source of energy in the world
supplying about 13% (55EJ/YR), which is equivalent to 25 million barrels of primary
energy(Mittal, 1997). Only one study of biogas yield from donkey dung has been found and is
shows that a batch 75 liter digester of 10 percent dry content gives a total of around 240 liter of
biogas with around 55 percent methane content after full digestion (The study also noted benefit
of co-digestion with poultry manure) ( Kannan, N. 2003). Assuming 50 percent dry content in
collected dung the overall potential would be 1600 m3 of biogas per year equivalent of 10,500
kWh or 730 kg of LPG worth ksh 180,000. This is a conservative estimation since it assume only
3.5 percent of all dung is collected.
The process of biogas production takes place in anaerobic conditions and in different
temperature diapasons. There are psychrophilic (temperature diapason 10-250C), mesophilic (25-
400C) and thermophilic (50-550C) regimes of bioconversion. Biogas reactors, working in a
thermophilic regime, can be introduced in agricultural farms where the number of livestock
exceeds 5. Biogas produced on such farms can be used not only for cooking and heating water,
but for dairy production as well. Anaerobic digestion (AD) can be defined as the conversion of
biodegradable material to biogas which comprises of about 60% methane and 40% carbon
dioxide. The process is performed by the activity of several different groups of micro-organisms
in the absence of oxygen Biogas technology involves the use of biogas digesters that are
constructed vessel in which animal waste and other bio-degradable materials are broken down by
bacteria in complete absence of oxygen to produce biogas. The biogas digester is free from theft
risks as compared to solar installations. Biogas consists of different component gases, mainly
methane (CH4), carbon dioxide (CO2), with traces of hydrogen sulphide (H2S) and hydrogen
(H2) gas (Bajracharya et al., 2010). Biogas is also a waste management technique because the
anaerobic treatment process eliminates the harmful micro-organisms. It is a heap source of
energy due to the feed stock is usually waste materials. The technology ensures energy
independence as a unit can meet the need of a family or community.
The digester slurry is a good fertilizer. Most of the pathogens are destroyed in the process of
anaerobic digestion (FAO 1996).However, the state of hygienisation of the effluent slurry of
biogas digesters strongly depends on the influent concentration in pathogenic microorganism, the
retention time and the temperature. High temperatures and long retention times are more
hygienic (SASSE 1988). If more than 55°C are achieved for one to a few days, inactivation can
be considered as efficient (SCHOENNING & STENSTROEM 2004).
The energy content of biogas is 9.8 kWh/m3 (Thours 2007). The anaerobic digestion process is
divided into four steps, hydrolysis, acidogenesis, acetogenesis and methanogenesis (Davidsson
2007; Leksell 2005). Studies done elsewhere show optimization of methane content of biogas
through co-digestion. Cow dung yield the highest biogas with methane content of 67.9%. Cow
pea yielded 56.2% methane content. The lowest methane content was produced by cassava
peelings with 51.4%.( Ukpai, P. A.2012). Donkey manure and cow dung were used as co-
substrates in the study. For co-digestion of cow dung and donkey manure gas production was
highest between 18-26 days. From 30 days and above biogas production decreased until it
became negligible because all the food in the digester had been consumed and there was no
supply of food for the methanogens. For cow dung, gas production increased as between 16-28
days(P Mukumba, G Makaka, S Mamphweli).
Co-digestion of donkey manure and cow dung is highly desirable for increasing methane yield (P
Mukumba. poultry droppings and donkey-dung combination as feed material can generate on an
average a total gas of 11352 l with an average methane content of 61.52% 0.5 m3 floating drum
type biogas plant yielding digested slurry, which contains an average of 2.42%, 0.84% and
0.70% of nitrogen, phosphorous and potassium, respectively(N Kannan, T Guruswamy, V
Kumar, 2003) A study has shown that anaerobic co-digestion of a mixing ratio of 25% cow
dung and 25% donkey dung co-digested with 25% goat dung and 25% horse dung produced the
biogas yield with the highest methane yield of 75% than the other mixing ratios(P. Mukumba,
…..)
Highest biogas yield was obtained from a mixing ratio of 50% cow dung to 50% donkey manure,
(Makumba et al)
PROBLEM STATEMENT
There is a high population of donkeys In Lamu county IIII. They litter the streets with their dung
as they transport merchandise from one point to another. The dung puts the residents at a risk of
getting infected with tetanus and the odor causes air pollution.
Most residents lack access to commercial energy sources which are costly.
The main perceived environmental issue on Lamu, by both residents and tourists, is waste;
donkey dung, lying on the beach and other open surfaces.(Kombo, 2011), Dung, primarily
available from donkeys, is not used today and ends up on the dumpsites. Since there over 5000
donkeys on the island the volume of dung is substantial, if each donkey produces two kilograms
of dung per day the resource base would be over 3000 tons per year posing environmental
pollution.
JUSTIFICATION
Energy is one of the prerequisites for growth of agriculture and industry. Its requirements are met
mainly through commercial energy sources whose prices in the recent years have increased
sharply and are continuously getting depleted.
Hence the urgent need to develop and exploit the alternative sources of energy such as biogas
obtained from donkey’s dung which Is readily available a nuisance in Lamu county.
As in the rest of Kenya, main cooking fuels for Lamu residents are traditional biomass as
agricultural waste; coconut shells, dung or maize stems, firewood; IIII mostly easily collected
branches or sticks and charcoal. Though cheap and renewable these fuels have issues.
Deforestation because of charring is a very urgent issue in Lamu district, population density is
not very high, though if all charcoal consumed on Lamu were produced there the island would
have large problem with deforestation. Alternative energy sources will decelerate environmental
degradation through pollution and deforestation.
OBJECTIVES
To assess donkey’s dung biogas productivity
To determine the presence of N, P and K in the donkey slurry from the bio digester for crop
fertilization.
To assess the presence of Clostridium tetani in the donkey dung before and after passing through
the Flexi bio digester
To compare quantity and quality of biogas produced from different levels of the two types of
animal dung
General Objectives:
To determine the amount of gas emitted from combination of cow dung and donkey dung
To evaluate donkey dung as a potential substrate for biogas production
Specific Objectives:
1. To compare the amount of gas produced from combinations of cow dung and donkey
dung.
2. To determine a mixing ratio of the feed stock and water that gives maximum amount of
biogas from combined feed stock( cow dung and donkey dung).
3. To determine the effect of feed stock substrate mixing ratios
4. To establish the presence of N, P, K in the sludge for crop fertilization.
Hypothesis.
1. Slurry from the bio – digester contains N, P, K. restate as below
2. Mixing ratio of substrate and water affects the amount of gas produced from each
substrate
3. Substrate mixing rations affect the amount of biogas produced.
4. 75% donkey dung and 25% cow dung level of combination produces the maximum
amount of biogas.
Can the hypothesis be stated in the Null format eg The slurry from the biodigester will
have the same N, P, K levels as those in the raw dung
Materials and methods
Raw materials and equipment:
Freshly voided donkey, and cattle wastes were collected from Lamu and Pwani University
respectively
The feedstock materials mainly donkey dung, cattle dung will be tested for biogas productivity in
twelve digesters for a retention period of 56 days under batch fed system and their performance
evaluated
The five treatments selected for the study will be:
• 25%donkey dung + 75% Cattle dung
• 50%donkey dung + 50% Cattle dung
• 75%donkey dung + 25% Cattle dung
• 100%donkey dung
• 100% cattle dung(control)
• A flexi bag digester will be chosen for each substrate combination.
• 15 identical flexi bag digester units will be used as experimental units.
• The investigation will be conducted in a completely Randomized Design (CRD) with
three replicates of each treatment.
Comparison between the two types will be carried out using the Analysis Of Variance tables
(ANOVA) Expand this statement to be more descriptive.
Experimentation:
The experiment will be conducted using a Randomized Complete Block Design (RCBD)
research design with 5 bio – digester as the blocks and 5 treatment levels. Samples of fresh
donkey dung will be ferried from Lamu while cow dug will be collected from Pwani university
farm. Prior to loading into the digester, stones, leaves, waste feed, sticks, and other foreign
matter were carefully picked from the wastes which were then properly stirred to break the
lumps into finer particles. A 25 kg charge (30%TS) of each waste type was measured and mixed
with 25 kg of water in a mixing tank; and stirred for about 20 minutes to ensure sufficient
dispersal of the waste particles and achieve slurry of regular consistency. The mixed slurry was
then poured into the digester tank and sealed properly to ensure air-tightness. Two other
concentrations of ratios 2:1 (50 kg of waste mixed with 25 kg of water) and 3:1 (75 kg of waste
mixed with 25 kg of water) were loaded. Three replicates were used for each experiment. All the
experiments were subjected to a retention period of 30 days each. All were exposed to ambient
temperatures which were within the mesophilic range and none was artificially heated.The whole
arrangements were fully set up on the experimental site, free of any shade to ensure maximum
reception of solar radiation. The ambient temperatures of the site were continually monitored and
measured daily. The arrangement was vigorously shaken twice daily, at 7.00am in the morning
and 7.00pm in the evening and biogas production was measured at 12.00 noon throughout the
30-day retention period used for every experiment. In each batch 3kg of each animal dung
combination will be weighed and placed in the digester unit then mixed with water at a ratio of
1:1 The gas holder will then be placed on the digester with the gas outlet sealed by the rubber
tube. The produced gas will then be discarded at intervals each time when the level in one of the
digesters reach 21 cm. At each discarding event the produced gas will be tested to examine the
presence of methane by ignition.
Try to insert experiment 1, 2 3 and 4 as per the objectives describing each in details of what will
be carried out.
PROPOSED BUDGET FOR DONKEY BIOGAS PROJECT
ITEM QUANTIT
Y
UNIT
COST
FREQUENCY TOTAL
SURVEY AND DATA COLLECTION
ENUMERATORS (MAN
DAYS)
5 2500 5 62500
DATA ANALYSIS 5 1000 1 5000
VALIDATION OF THE
DUNG MENACE(DAYS)
2 10,000 1 20000
STATIONARY 3 2500 3 22500
DUNG COLLECTION AND
TRANSPORTATION
0
FLEXI - BIODIGETER 15 30,000 1 450000
MIXING BUCKETS 15 500 1 7500
DUNG COLLECTOR FOR
TWO MONTHS
2 5000 2 20000
DUNG TRANSPORTATION 3 20,000 1 60000
TOTAL 647500
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MATERIALS AND METHODS
livestock farms at the Institute of Agricultural Research
and Training (IAR&T), Moor Plantation, Ibadan, Nigeria.
Nine 220-litre black-coated, batch type, sheet metal
digesters which incorporated a water tank as well as
iron sponge and saw dust sealed in a separate cylinder
were used in this 3x3 factorial experiment.
Biogas
samples were obtained at the beginning, and towards
the end of the detention period. Biogas quality was
measured using a gas detector. Volume measurements
of biogas produced were done by water displacement.
The experiment reported in this present study
is part of a wider set of biogas production experiments
which were conducted in the months of February to
May, 2008. Energy to run the experiments came
entirely from solar radiation. According to Fagbenle
(1991), the monthly average daily extraterrestrial solar
radiation for Ibadan, Nigeria is as shown in Table 1.
Table 1:
Monthly average daily extraterrestrial solar radiation on horizontal surface (KJ/m
2
) for Ibadan, Nigeria (Lat
7.43
0
N, Long 3.80
0
were well stirred and digested in a 3x3 factorial experiment using a retention period of 30 days and within
the mesophilic temperature range. The waste: water mixing ratios of slurry used were 1:1, 2:1 and 3:1 by
mass. Three replicates were used for each ratio. Two hundred gram samples of each animal waste type
were obtained before and after experimentation and analysed for chemical constitution. All the readings of
the biogas yield were analysed using the Duncan Multiple Range Test (DMRT). Biogas yield was
significantly (p < 0.05) influenced by the various factors of animal waste (F=86.40, P< 0.05), different water
mixing rates (F=212.76, P< 0.05) and the interactions of both factors (F=45.91, P< 0.05). Therefore, biogas
yield was influenced by variations in the mixing ratios as well as the waste types used. The 1:1 mixing ratio
of slurry resulted in biogas productions of 20.8, 28.1, and 15.6 l/kgTS for poultry, piggery and cattle wastes
respectively. The 2:1 ratio resulted in 40.3, 61.2 and 35.0l/kgTS while the 3:1 ratio produced 131.9, 117.0
and 29.8l/kgTS of biogas respectively. Therefore an increasing trend was observed in biogas production as
mixing ratio changed from 1:1 to 3:1. For cattle waste however, production decreased from ratio 2:1 to ratio
3:1. The N, P, K values were highest for poultry waste (3.6, 2.1, and 1.4% respectively) and least for cattle
waste (2.2, 0.6, 0.5% respectively). Organic carbon was highest for cattle waste (53.9%) and least for
poultry waste (38.9%). Reduction in C/N ratio for each experiment ranged from 1.1 to 1.9%.
Conclusion and application of findings
: This study found that for poultry and piggery wastes, slurries mixed
in ratios 3:1 waste:water produced more biogas than those of 2:1 and 1:1 ratios. For cattle waste, the 2:1
mixing ratio produced the most biogas. This paper therefore recommends a livestock wastes: water mixing
ratio of 3:1 for poultry and piggery slurries, and 2:1 for cattle slurry for maximum biogas production from
methane-generating systems, given 30% TS content.
Key words:
Anaerobic digestion, biogas, cattle waste, piggery waste, poultry waste.
Journal of Applied Biosciences 22: 1333 - 1343
ISSN 1997–5902
Adelekan & Bamgboye.
....................................
J. Appl. Biosci. 2009. Biogas production with farm waste
1334
INTRODUCTION
Scientific interest and efforts in researching into
biogas production technology are still relevant
because of the often very high costs of energy
supply worldwide. Another reason for their
relevance is the fact that the rampant use of
firewood for domestic cooking in low income
countries invariably results in the destruction of
forests which is harmful to the environment. Also,
the use of firewood, kerosene and charcoal in
households has adverse effects on human health
(Adelekan & Adelekan, 2004). Furthermore, using
waste biomass to produce energy can reduce the
use of fossil fuels, reduce greenhouse gas
emissions and reduce pollution and waste
management problems (Vetter
et al.,
1990;
Marshall, 2007; Inderwildi and King, 2009). EEA
(2006) pointed out that by 2020, the equivalent of
19 million tonnes of oil will be available from
biomass, of which 46% will be from biowastes
mainly municipal solid wastes, agricultural
residues, farm waste and other biodegradable
waste streams.
The objective of the research work being
reported in this paper was to investigate the effect
of mixing ratio of slurry on biogas productivity of
wastes from poultry birds, pigs and cattle. Biomass
represents a continuously renewable potential
source of methane and thus offers a partial
solution to the eventual prospects of fossil fuel
depletion. In addition, biomass can be
economically converted to biogas at a variety of
scales and thus can be tailored to supply local,
regional and nationwide biogas needs.
It has been discovered that, under aerobic
conditions, living plants also produce methane
which is significantly larger in volume than that
produced by dead plants. Although this does not
increase global warming because of the carbon
cycle (Keppler
et al.,
2006), it is not readily
recoverable for economic purposes. However, the
methane which is recoverable for the direct
production of energy is from dead plants and other
dead biomass under anaerobic conditions. Biogas
is a flammable gas produced by microbes when
organic materials are fermented in a certain range
of temperatures, moisture contents, and acidities,
under air–tight conditions. Anaerobic digestion is a
process through which organic materials are
decomposed by bacteria in the absence of air to
produce biogas. The digestion process itself starts
with the bacterial hydrolysis of the biomass so as
to break down carbohydrates and other insoluble
organic polymers. After the chemical break down,
various kinds of bacteria convert the materials into
different gases and organic acids in several stages
(Ciborowski, 2004). Methanogenic bacteria finally
convert these products into methane and carbon
dioxide (Fergusen and Mah, 2006; Anaerobic
Digestion Reference Sheet, 2007). UNDP (1997)
stated that anaerobic digestion facilities constitute
one of the most useful decentralized sources of
energy supply and they are less capital intensive
than conventional power plants.
Many publications have pointed out that
simple, home and farm-based anaerobic digestion
systems have the potential for supplying cheap,
low cost energy for cooking and lighting in
developing countries (Doelle, 2001; Friends of the
Earth, 2004; Cardiff University, 2005). Many
developing nations meet significant amounts of
their energy needs through biogas particularly in
the rural areas. The biogas support program in
Nepal has installed over 150,000 biogas plants in
the rural areas (AEPCNEPAL, 2009) while the
biogas program in Vietnam has led to the
installation of more than 20,000 plants throughout
the country (SNV, 2009). Also, in Rwanda, the
Kigali Institute of Science and Technology has
developed and installed several large-scale biogas
plants at prisons to treat sewage and provide
biogas for cooking (KIST, 2009). Even in
developed countries, significant potential for
biogas use still exists. For example in the United
Kingdom, biogas is estimated to have the potential
to replace about 17% of vehicle fuel (Claverton
Energy Conference, 2008). In Sweden, a biogas-
powered train has been in service since 2005
(Svenskbiogas, 2005).
Options for biomass exploitation include
plant materials and livestock wastes mostly.
Several researchers have reported biogas
production from various materials including pigeon