In this chapter the data gathered from observation, Supplementary and questionnaire are presented and discussed. Qualitative data obtained through interviews and observations are discussed qualitatively. The results help for visualization of biogas utilizations status and its contributions in greenhouse gas emission reduction in four selected kebeles of Guduru district.
Biogas Potential of the Guduru District Based On the Existing Cattle Population
Households also need to be assured of reliable and cheap sources of raw materials (substrates) for production of biogas energy. There are many potential substrate areas for biogas electricity production; it includes plant waste, animal waste, household waste, waste and water, as well as human waste. However, according to the current conversion technology, the main raw material for biogas energy production in the Gudulu region is cow manure. However, statistics on the cost of biogas energy produced from animal waste; the substrate is not easy to use alone, now and in the future. Total biogas energy potential and estimated energy recovery from livestock were calculated using the Organization for Economic Co-operation and Development (OECD) method (Taşdemiroğlu, 1988).
The total biogas energy capacity of animal manure is approximately 1740 ktoe. Of this, 1189 ktoe is the total energy potential from cattle waste, 490 ktoe from sheep and goats, 48 ktoe from pigs and 13 ktoe from chicken. At a 30% recycling rate, the total recoverable resource is approximately 523 ktoe, of which 357 ktoe (68%) comes from cattle waste, 147 ktoe (28%) from sheep and goat waste, and 15 ktoe (3%) from sheep and goat waste. ) is obtained. from self-feeding pig farm waste, 4 ktoe (1%) from chicken manure.
Livestock Population in Guduru Livestock
Ethiopia's livestock farming ranks second in Africa and ninth in the world. In livestock, there are more than 49.3 million cattle, 30 million sheep, 1 million camels and 4.5 million horses (horse-like or horse-like). More than 82% of all cows are one year old or older. Livestock contributes significantly to the livelihood of 80% of the rural population. Livestock farming is an important part of agriculture and is closely linked to land/soil and water management (CSA, 2009).
As seen in Table 1 below, there are a total of 33,6417 animals according to 2018 data from Güduru District Agriculture and Rural Development Office; 176 thousand 850 cattle, 22 thousand 610 sheep, 22 thousand 178 goats, 96 thousand 320 chickens, 4 thousand 866 horses and 13 thousand 593 donkeys were found in the district headquarters. The daily production of livestock alone is approximately 176.8500 kg to 2652750 kg, which can theoretically produce 40675.5 cubic meters to 106110 cubic meters of biogas. Also the annual harvest is approximately 645,502,500–968, 253, 7575755,502,500–968,253 cubic meters to 38730150 cubic meters. Among the 336,417 animal species, cattle and poultry are the most common; other names are given in Table 1 below.
According to Werner, Stohrami Hccs (1989), urine of a cow = 10–15 kg manure/day, oil production per kilogram of cow manure = 0.023–0.04 m3 Oil production per kilogram of chicken manure = 0.065–0.116 m3, food fuel required for cooking = 0.2–0.3 m3 per person, fuel required for lighting = 0.1–0.15 m3/hour.
Distribution and Operation of Biogas Constructed and Facilities Status
Biogas Facilities Built in the Region
Biogas technology is a useful tool for energy development. The findings show that biogas distribution in Ethiopia is not significant in terms of its demand and potential. The allocation and completion dates of biogas facilities in the four selected provinces are briefly explained below.
Biogas Plant Visit and Completion Date
The findings show that the distribution of biogas technology in Ethiopia is insignificant enough to affect the demand and potential. The total number of biogas plants in the four selected kebeles (i.e. Guto Abay, Hula guto, Kanani and Ilamu Tarako) during the 3-year period from 2007 to 2009 was 20 (as shown in Fig. 2 below).
In particular, EC has the highest number of biogas plants built in 2007, and 6 out of 10 plants visited (30%) were installed in 2008 E.C. Figure 2. Shows the distribution of biogas plants among the four kebeles in Guduru district. Although insignificant, awareness about the distribution of biogas plants has increased in recent years. However, the number of biogas facilities installed in many provinces of the decreased in 2009 E.C. Among other reasons, this may be due to additional supply and costs due to high inflation. Additionally, failure of the biogas plant due to lack of suppliers will lead to rejection of the installation.
Biogas Plant Locations
Out of 20 biogas plants in Hula Guto during the study period, 6 (30%), 5 (25%), 5 (25%) and 4 (20%) biogas plants Guto Abay, Illamu Tarako and Qanani kebeles in Table 2. The difference in biogas installation between the four kebeles is small, probably because they are close to various barriers to changing technology (e.g. equipment, labor, technology, skills, etc.). The diffusion or transfer of biogas technology refers to a system in which there are many interactions between technologies such as equipment, "software" (technology, know-how and knowledge), "human capacity, governance, and environment" and the end result. ” delivering the product (including marketing capabilities) to end users. Therefore, the distribution of biogas facilities varies from kebele to kebele.
Application/Purpose of Biogas System Installation
Participants were asked to provide the most important information about their biogas installations. According to them, the most important applications are cooking, lighting and agricultural fertilizers rather than wood and energy. 12 (60%) of the biogas facilities are not used for cooking, lighting and agricultural fertilizer purposes, 6 (30%) are not used for cooking and lighting, and 2 (10%) are not used in public services because the biogas facilities are not working in Table 3 below.
The biogas generated is for mainly household cooking and lighting while the slurry is used as a fertilizer in agricultural production as shown below in Fig. 3.
Types of Biogas Plants
Among the 20 biogas plants evaluated, the performance of biogas plants directly depends on the quality of construction, equipment, quality control and maintenance performed during and after construction. Therefore, there must be a plan for continuous monitoring or control of the structure of the biodigester plant. Below are some observations and information obtained during the investigation. The materials used in 20 SINDU model biogas digesters consist of cement, sand, gravel and stone, while one Chinese biogas digester is made of brick, cement and sand, and another Chinese biogas digester is made of stone, cement and sand.. Plant construction requires skilled workers and requires special training. The design is popular because this type of facility can be built on site using local materials, including cement. Biogas digester is a physical structure also known as biogas plant or anaerobic digester. A vacuum is a significant underground, enclosed space where users deposit crops, animal waste, human waste, and water. When the necessary bacteria form in the digester, biowastes are mixed with water in a predetermined ratio and stored for approximately 50–60 days (FOA, 1997).
Size of Biogas Plant
Scale of each biogas facility in the study area is 6 cubic meters.The digester model adapted from Nepal uses a fixed dome and is called the SINDU digester (SINDU means "prepared" in Ethiopian). The model is available in four different sizes: 4m3, 6m3, 8m3 and 10m3 (Eshete, Sonder and Heegde, 2006).
However, the most commonly used biogas digester sizes in China are 8 cubic meters and 10 cubic meters. Dome sizes for home biogas equipment can vary depending on family size, amount of substrate available, how much biogas is needed, and budget. Capital investment. The number of substrates determines the size. The size also depends on the storage time of the slurry and this is usually determined by economic factors, with the storage time the volume required for the biogas plant increases and eventually more investment is required. Therefore, the amount of biogas produced depends on the amount and nature of the fermentation slurry, temperature and storage time in the digester. Gas production is encouraged by high, uniform temperatures, long retention times and through mixing of slurry. In contrast, gas production is adversely affected by low and fluctuating temperatures (20°C – 26°C), short retention times and poor mixing (Sasse; 1988).
Functional Status of Bio Digester
All biogas digester were in good condition out of all 20 biogas plants only two plants found in IlamuTarakos was not functional the non-functioning of the plant according to the respondent was due to a) Technical problems (i.e. Crack, Blockage, scum formation, stove damage, and lack of feedstock/water), b) Poor management (i.e. lack of interest/care and maintenance), c) Poor design, lay out and construction, d) abandoned, and any of these combinations to poor operation ;the inadequate amount of gas ,dung was feed once in four days .However the users were satisfied with the functioning of the plant the gas produced was sufficient enough to meet their cooking requirement.
The biogas stove was used for cooking for five to six hours the whole day, preparing the three meals and tea for the family. However during winters when the ambient temperature drops the decomposition slows down: hence very little gas is produced and is not sufficient to cook food, but can be used make tea or warm up food during this months the households either use LPG cylinders for cooking or dung cakes made of the dried bio slurry: which was in excess after being used in the fields.The study attempts to evaluate the overall functional of biogas plants based on: existing physical status and functioning of different components; functional status of the whole system; present level of benefits (hours of gas use per day); and levels of user’s satisfaction on the impacts of biogas plants on them. Most biogas plants have different features for efficient and trouble-free operation.
During the on-site inspection, the current status of the different products of the biogas plant was analyzed in detail and the quality, management and results of the construction were evaluated and placed. According to the physical inspection of the biogas plant during the on-site inspection, the physical condition and cleanliness of different products of the biogas plant are now divided into four parts: different: excellent, good and not working. Lack of skills in biogas plant construction and maintenance is often considered one of the main limitations in the use of biogas technology in developing countries. When problems arise in factory work, one of the complaints is the lack of support (Erdogdu, 2008; Mwakaje, 2008).
Biogas digester maintenance requirements typically include: Repair and replacement costs of gas valves, lights, furnaces, and waste gas treatment costs. Expertise is also important when choosing the right location for a biogas plant to ensure the plant operates well. Site selection and proper construction will facilitate the digestion of food and mud. Some studies have shown that it is important to choose the right location for biogas development in a region, district or community (Walekhwa et al. 2009). Polpraset et al. (1986) confirmed that the main operational problems in biogas plants are caused by excessive waste in the biogas digester due to poor quality of the plant due to the lack of specific plant substrate. In addition, the facility must be filled with liquid waste approximately every five years for a good life. According to a study conducted by the Ethiopian National Biogas Program in 2006, approximately 60% of biogas plants are not in operation, meaning they cannot produce gasoline. Fixed dome and floating children's venues account for 68% and 16% respectively, which shows that fixed dome is better than children's venues in Ethiopia (Eshete et al., 2006), so most places cannot afford it. Business problems with domestic biogas plants include uninsulated pipes for cattle, damaged stoves and biogas plants. The impact of minor problems is also due to the lack of nearby services; many problems can be solved by skilled, low-skilled workers in less than half a day.
Existing conditions of Digester Attached with Dome (Cabinets)
The current state of 8 (40%) factories have been eliminated and 2 (10%) plants in the study area are not doing well (cannot function). The gas produced in the digester and stored in the dome (gas tank) is sent to the pipeline through the main gas valve located in the middle of the dome. In almost all cases, turrets are constructed to ensure that the main pipeline is protected from the risk of damage from humans and animals (Prakash, 2005). Existing conditions of Inlet Tank with Mixing Device and Inlet Pipe
The current condition of the water inlet and water inlet pipe tank in the tank with the mixing device is very good (i.e. working smoothly) in 12 companies (60%) and 6 companies (30%). The factory is in good condition (i.e. working flawlessly), 2 (10%) are factory defects (i.e. defective and not working). The inlet tank should be placed at the correct location of the inlet pipe, at the end of the outlet, opposite the outlet opening on the longitudinal center line of the digester to complete the digestion of the sludge, followed by the storage period (Karki, I. L. et. al., 1994).
However, some of these situations are not implemented. The short storage time may be due to the slurry leaving the outlet without leaving all unchanged species. Sometimes bubbles, pressure and odor in the outlet port and sludge indicate biogas flow, causing incomplete biodegradation of organic matter entering the biogas digester.
Current Status of Biogas Outlet And Transfer Outlet
There is an open outlet called manhole at the outlet, a tank called outlet displacement, and the outlet is suitable for opening at the appropriate height of the outlet wall. The manhole is set in a position opposite the diameter of the water inlet pipe to prevent short-circuiting of the supply. This opening serves many purposes: as a manhole or access for workers during plant construction and maintenance, to clean equipment, to mix slurry, a long shaft or shaft is used to prevent slurry from forming lumps (foam) in it. It is also used to promote the outward movement of sludge particles caused by gas accumulation in the fuel, and the inward movement of sludge from moving parts when oil is used, the oil has sufficient pressure. Reaches its places of use (Madanet, 2004).
However, since most of the factories in this study are connected to toilets and users are not aware of the quality of the manholes in the water outlets, the use of the above manholes has not been used so far. In addition, since the electrical outlet is built into the ground and contains sewage sludge, it is difficult to check whether its structure is good. However, analysis of this survey showed that the presence and cleanliness of the factory exit system was good in 8 schools (40%), good in 10 schools (50%) and poor in 10 schools (50%). 2 (10%) plants.
Current Status of the Main Pipeline and Tower
The gas produced in vacuum and stored in the dome (gas storage tank) is sent to the pipeline through the main gas valve located in the center of the dome. This main gas pipe is protected by a wall block called a "turret" built around the pipe. For the plant under review, there are 1/2 to 1 inch diameter GI (galvanized steel) pipes used as main water pipes at the SINDU plant. In almost all cases, turrets are constructed to ensure that the main pipeline is protected from the risk of damage from humans and animals (Prakash, 2005). However, the analysis results showed that the availability and cleanliness of essential oils were good in 14 (70%) factories, 4 (20%) factories were good, and 2 (10%) offices were not good (unsuitable). function). This means that the presence and cleanliness of main valves and turrets has a significant impact on the operating level of the plant.
User and Owner Satisfaction
The most important factor in measuring the success of any product or service is user satisfaction. User satisfaction relates to the level of usefulness, comfort and value the end user receives. The greater the value, comfort and value of the product, the higher the final customer satisfaction. Participants were encouraged to rate their facility's performance by asking a variety of direct and indirect questions. We carefully analyze the user's feedback to determine whether they are satisfied with their factory's products and the impact on them. User satisfaction is divided into four different categories: excellent, good and poor. These factors are also the main reasons why biogas users are interested in biogas plants and recommend their widespread use. The use of mud provides significant financial support to users and incentives to non-users.
The basics of reporting the interests of different users are: sufficient cooking oil, easy cooking, nutritious food, economic benefits, technical benefits health, environmental benefits, no equipment problems, saving time and reducing labor. As seen in the table where people were asked whether they were satisfied with the operation of the biogas plant and analyzed according to the above reasons, 11 participants (55%) evaluated their satisfaction as very good, 7 participants (35%) evaluated their satisfaction as good, and 2 participants (35%) evaluated their satisfaction. 10% of respondents are dissatisfied; This is because users feel that the facility is not functioning well because they have not properly checked the quality of the facility and/or due to construction issues.
Wim et al (2007) said that when deciding to install a biogas plant, it should be realized that the system requires constant monitoring and regular maintenance and repair, and this should not be guessed. Over the past few years, most digester failures have been caused by management problems rather than business problems. Thanks to good design, proper operation and management, all problems in biogas plants can be reduced or completely eliminated.
Attitudes towards the Use of Technology At Home
Studies and recorded data show that over 18 (90%) of Biodigester owners and their families have a positive attitude towards technology and 2 (10%) of all Biodigester are located in Illamu. Tarako kebeles. The author has a negative attitude towards this machine because since it was built, its vacuum does not work or the gas is not enough to cook every day. The farmer has invested more than 9,000 ETBs and needs further research to identify the problem.
Gas Produced For Main Meals
According to interviewees and observations, the gas produced from 18 (90%) biogas digesters is enough to meet the family's daily cooking needs and corrosion of equipment are important processes. The 2 (10%) digesters that operate without gas for daily family food consumption have biogas leakage issues because some commercial buildings still operating at the time of the visit are not working well due to not enough gas. When asked about the reasons for the decline in oil production, respondents cited insufficient oil for the plant, poor construction and operation, maintenance and regular maintenance, reduced fuel consumption during cold/rainy weather, and a combination of the above.
Water Availability
The use Daily access to water per household in rural areas varies from 0.5 hours to several hours (Hutton et al., 2006). According to the report, 71 percent of rural households in Ethiopia live within 1 kilometer of a well, and 29 percent live more than 1 kilometer from a well. Therefore, the hypothesis is that the average journey was 1 km, the journey time was 30 minutes and 60 liters were collected twice a day to make the slurry.
Combining this information, the estimated writing time is approximately 60 minutes per day. Biogas feeding requires a mixture of equal proportions of fertilizer and water. The larger the biogas, the more fertilizer and water is needed. If there is no well nearby, access to water may be a problem. According to the respondents' information about the availability of water near the biodigester, 15 (75%) of the households with biodigesters have sufficient water, while 5 (25%) households have insufficient water.
Waste Water Use
With continuous cultivation, organic matter and nitrogen disappear rapidly; phosphorus and other nutrients increase slowly but steadily (Borlaugh and Dowswell, 1995). The slurry obtained by obtaining energy from manure is a very good fertilizer. This plant, rich in nitrogen, phosphorus, potassium and humus, supports good soil and higher yields (Marhain, 1992). However, 18 (90%) of the eighteen respondents agreed to use bio slurry in their fields to increase yield and avoid using slurry for plant failure. About 2% (10%) of the respondents do not use bio slurry because field research and data show that biogas plant owners pay a lot of money for biogas production and ignore the use of biogas sludge.
Retention Time
Retention time is the average time that gives how much slurry remains in the digester for the action of methanogens. It is difficult to find the number of growing days of the plant; retention time or hydraulic retention time (HRT) as digesters are fed continuously. Additionally, employees often use different payment methods and fees. However, workers reported that most of the manure used for the first time since the beginning of construction was collected outside the dome, and construction took one to two months, depending on the number of cows there. Therefore, the stored manure begins anaerobic digestion outside the dome. According to interviewees, gas production begins approximately two to three weeks after the digester is filled with output.
Mixing Application
Mixing application is done manually in each digestion. This is done with hands or tree branches as shown in Fig. 13. In addition, half of the workers mix fertilizer and water based on their experience instead of using equal amounts. The researchers also observed five biogas users injecting manure into digesters three to four days a week. The following people were photographed during their visit to Hula Guto kebeles in Guduru District.
Evaluating Greenhouse Gas Emission Reduction Based on the Fuel Wood Replaced
Biogas plants also help to reduce greenhouse gas (GHG) emissions. Since carbon emission trading is not practiced in a household level here in Ethiopia, the environmental benefits from biogas is considered an economic benefit and not financial. Biogas helps reduce greenhouse gas emissions by displacing the consumption of fuel wood, dung cake and kerosene. The biogas is assumed to be produced on a sustainable basis, and therefore the CO2 associated with biogas combustion is reabsorbed in the process of the growth of the fodder and foodstuffs by the bio-slurry as fertilizer from the biogas plant. In the case of fuel wood, if it is consumed on a non-sustainable basis, then all the CO2, CH4 and N2O emissions that are associated with the combustion of fuel wood can be accounted as being displaced when replaced by a biogas plant.
House Hold Fuel Wood Consumption
Before biogas installation, the people in the rural communities were mostly dependent upon biomass such as firewood, agricultural residues, dung cake etc. Cook meals for their family. These chemicals produce smoke, which women and children in poor kitchens are more likely to inhale. Smoke in the kitchen is a health problem. Research shows that biogas families in the study area used Wanza acacia for cooking and Injera for wot porridge and coffee/tea before setting up biogas plants. However, after the development of biogas, domestic gas began to be used only in injection production. Emission coefficients per tonne of biogas, according to the Intergovernmental Panel on Climate Change's (IPCC) Guide to National Greenhouse Gas Inventories (IPCC, 1995). Unstable fires produce approximately 1.5 tonnes of carbon dioxide and 2.5 tonnes of carbon dioxide. 1,000 liters of kerosene were burned. Therefore, after installing a biogas plant, each family can reduce approximately 6.1 tons of carbon dioxide equivalent per year. As can be seen in Table 6, before the biogas facility was established, the surveyed households were using 3072 kg of fuelwood per household. Annual carbon dioxide equivalent (CO2e) is 4608 kg/HH/year. Reducing the use of biogas energy 1536 kilograms of fuelwood is consumed for cooking oil each year (greenhouse emissions are 2304 kilograms).
Household Health
The interviewed families also use kerosene to illuminate the house while studying and to complete household chores at night. As shown in Table 7, before the installation of the biogas plant, the average household consumed only 2.67 liters of kerosene per month, 32.04 liters of kerosene per year, and only 2 to 3 hours of good light visibility in a day. This gas releases 89.72 kilograms of carbon dioxide equivalent (CO2e) gas into the atmosphere every year. Once biogas is installed, all biogas houses use biogas lamps for light. This has the potential to reduce greenhouse gas emissions into the atmosphere by up to 89.72 kilograms of CO2e per household per year.
Reduction of Carbon Dioxide (C0 2 ) Emission
The reduction in carbon dioxide emission from functional biogas plants was calculated to quantify the environmental impact of biogas technology. (Shakti, 2009) calculated the carbon dioxide emission from a 2 cubic meter biogas plant in Bangladesh, using this value the emission reduction from biogas plant in four kebeles under consideration was calculated .The total capacity of the plant functioning in the four kebeles is 108 m3 as one plant has total capacity of 6m3 so the capacity of all the plant is (6 x 18) m3, 2 m3 capacity of biogas plant can save up to 2.2 ton of CO2 per year (Shakti, 2009). Thus using this factor we can easily estimate the total saving of carbon dioxide emission from the surveyed biogas plants. 2m3 can save up to 2.2 CO2 ton / year. 1 m3 can save up to (2.2/2) = 1.1 CO2 ton / year. 108 m3 can save up ton (1.1x108) = 118.8 CO2 ton / year.
The outcome was significant as only 18 digesters can bring such a reduction if this technology is used more appropriately and at a wider scale, it can further reduce the emission to a great extent. Indirect environmental benefits include smoke free kitchens as using biogas release no soot, which is released in the case of burning dung cakes or fuel wood.
Estimating the Decreased in Deforestations of Using Biogas
Biogas plant installations also have a direct impact on the local environment. Local environmental benefits occur as part of switch away from biomass to cleaner fuels biogas energy and it is also considered as economic benefit. Essentially \this results in none of trees will be cut down in an unsustainable manner. Local effects of planting trees; soil erosion, desertification and landslides in the plateaus. These costs are many but uncertain and difficult to value the business, but another way to value the business is through replacement costs to prevent future effects of deforestation of the business (expenditure avoidance). This essentially means that the replacement value is the same as if the trees were constantly falling. Transfer value is the value of replanted trees with labor costs added to the value of the saplings.
Jargstorf (2004b) estimated that saving 6 tonnes of fuelwood per year is equivalent to saving 1 hectare of eucalyptus forest cover. This hectare of eucalyptus forest can save up to 5,000 ETB in cultivation. According to the above estimates, this study shows that the development of domestic biogas in rural households can save 1536 kilograms of fuel, which will save 0.266 hectares of forest per year, which is equal to 1330 ETB in afforestation costs.