The Potential for Urban Anaerobic Digestion in Quelimane
A model and feasibility assessment of a small scale system implementation Minor Field Study
Sophie Rudén Matilda Stendahl
Handledare:
David Stoltz Boris Atanassov
AL125x Examensarbete i Energi och miljö, grundnivå
Stockholm 2016
i This study has been carried out within the framework of the Minor Field Studies Scholarship Programme, MFS, which is funded by the Swedish International Development Cooperation Agency, Sida.
The MFS Scholarship Programme offers Swedish university students an opportunity to carry out two months’ field work, usually the student’s final degree project, in a country in Africa, Asia or Latin America. The results of the work are presented in an MFS report which is also the student’s Bachelor or Master of Science Thesis. Minor Field Studies are primarily conducted within subject areas of importance from a development perspective and in a country where Swedish international cooperation is ongoing.
The main purpose of the MFS Programme is to enhance Swedish university students’ knowledge and understanding of these countries and their problems and opportunities. MFS should provide the student with initial experience of conditions in such a country. The overall goals are to widen the Swedish human resources cadre for engagement in international development cooperation as well as to promote scientific exchange between universities, research institutes and similar authorities as well as NGOs in developing countries and in Sweden.
The International Relations Office at KTH the Royal Institute of Technology, Stockholm, Sweden, administers the MFS Programme within engineering and applied natural sciences.
Erika Svensson Programme Officer
MFS Programme, KTH International Relations Office
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Abstract
The Municipality of Quelimane, the fourth biggest city in Mozambique, aims to apply an EcoCity concept in the city. Therefore, the municipality initiated a waste-to-energy project in order to improve the lacking waste management, valorize resources and lessen the burden on the environment. The purpose of the current project was to investigate the potential for implementing a waste-to-energy system in Quelimane. In particular, the technology of
anaerobic digestion. This technology had been identified as the best alternative based on local conditions according to a study performed by students at KTH, the municipality of Quelimane and GreenLight about waste-to-energy in Quelimane the spring of 2015.
The present project was performed during eight weeks in Mozambique; five weeks in the capital Maputo and three weeks on-site in Quelimane, where the collection of data mainly was made in Quelimane. The gathered information resulted in a model for a small scale anaerobic digestion system in Quelimane. An assessment of the potential for an
implementation of an anaerobic digestion system in Quelimane was determined using a feasibility assessment tool.
The study was performed using the following methods: literature study, interviews, surveys, on-site observations, modelling and by using a feasibility assessment tool.
The analysis performed with the feasibility tool identified the socio-cultural attitude towards the technology and the willingness among the residents to use the end products as key factors for a successful implementation. The attitude towards the technology was determined as mainly positive and the willingness to use the end product high. The strong involvement and initiative from the municipality were also identified as key factors and determined as positive.
The environmental, policy and legal and the technological aspects of the system are other identified key factors were mainly identified as positive according to the feasibility assessment tool.
However, there is currently no end user for the small scale plant and no established funding for the project. This altogether results in a current marginally high potential for the
implementation of a small scale anaerobic digestion plant, with good chances to increase the potential in the future.
Keywords: waste-to-energy, anaerobic digestion, waste management, feasibility, potential, implementation, small scale, pilot project, developing countries
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Abstracto
O Município de Quelimane, a quarta maior cidade de Moçambique, visa a implementação do conceito EcoCity na cidade de Quelimane.
O Município, portanto, iniciou um projecto de transformação de resíduos sólidos em energia.
O projecto visa melhorar a gestão de resíduos na cidade, valorizar e diminuir a pressão sobre o meio ambiente. O objectivo do projecto foi investigar o potencial para a implementação de um sistema de transformação de resíduos em energia, em Quelimane. Em particular, a tecnologia de digestão anaeróbica. Esta tecnologia foi identificada como a melhor alternativa com base nas condições locais, de acordo com um estudo realizado pela KTH - GreenLight no segundo semestre de 2015.
O presente projecto foi realizado durante oito semanas em Moçambique, dividido entre cinco semanas em Maputo e três semanas no local, em Quelimane. A recolha de dados do campo foi principalmente feita em Quelimane. A informação recolhida resultou num modelo para um sistema de digestão anaeróbia de pequena escala. Uma avaliação do potencial para a
implementação deste sistema de digestão anaeróbia em Quelimane foi determinada utilizando a ferramenta de avaliação de viabilidade.
O estudo foi realizado utilizando os seguintes métodos: revisão bibliográfica, entrevistas, questionários, observações no local, modelações e usando uma ferramenta de avaliação de viabilidade.
A análise realizada com a ferramenta de viabilidade identificou dois factores-chave para uma implementação bem-sucedida: 1) a atitude sócio-cultural para a tecnologia e (2) a vontade entre os moradores para usar o gás produzido para fins energéticos.
A atitude em relação à tecnologia foi identificada como sendo principalmente positiva e a vontade de usar o produto final foi identificada como sendo alta. O forte envolvimento e iniciativa da parte do município também foram identificados como factores-chave. Estes dois aspectos foram identificados como positivos. Os aspectos do sistema em termos tecnológicos, ambientais, políticos e legais também foram identificados como positivos de acordo com a ferramenta de viabilidade.
No entanto, não há actualmente nenhum usuário final para o biodigestor de pequena escala e não existe financiamento estabelecido para o projecto. Em suma, esta análise mostra um potencial ligeiramente elevado para a implementação de um biodigestor de pequena escala, com boas chances para aumentar o potencial no futuro.
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Sammanfattning
Moçambique anses vara ett av de fattigaste länderna i världen, men efter att landet blev självständigt från Portugal år 1975 och det långdragna inbördeskriget tog slut 1992 börjar Moçambique nu visa en positiv ekonomisk utveckling. Quelimane, landets fjärde största stad sett till invånare, har utvecklats i samma positiva riktning de senaste åren. En av
anledningarna till Quelimanes positiva förändring är den sittande borgmästaren, Manuel de Araújo, som har åstadkommit flera praktiska förbättringar. En av hans visioner är att applicera ett EcoCity-koncept på staden. Syftet med det är att minska användandet av naturresurser och öka den ekonomiska tillväxten där ett led i utveckling är en effektiv avfallshantering och en hållbar energiomvandling. För att uppnå dessa två syften och på så sätt även främja hållbar utveckling i staden ansågs införandet av ett waste-to-energy system vara en bra teknisk lösning. Målet med detta projekt var därför att undersöka möjligheten att implementera ett småskaligt waste-to-energy system i Quelimane, där rötning var den teknologin som enligt en undersökning utförd av studenter på KTH i samarbete med kommunen i Quelimane och GreenLight om waste-to-energy i Quelimane från våren 2015 ansågs vara bäst lämpad baserat på lokala förhållanden.
I syfte att bestämma potentialen för implementeringen av en rötningsanläggning utfördes en litteraturstudie där förutsättningarna i Moçambique undersöktes och den mest lämpade designen för anläggningen fastslogs. Studien utfördes under totalt åtta veckor i Moçambique med tre veckors fältstudie i Quelimane. För att samla information utfördes intervjuer,
frågeenkäter, observationer och modellering samtidigt som ett verktyg användes för att bestämma potentialen. Utifrån den information som samlades in skapades en teoretisk modell för en småskalig rötningsanläggning med syfte att fungera som ett pilotprojekt. I modellen identifierades de omistliga faktorerna för implementering av en rötningsanläggning för både stor och liten skala samt yttre och inre hot för liten skala.
Den sociala och kulturella attityden mot rötningstekniken var positiv och viljan att använda slutprodukterna hos invånarna var hög vilket enligt det använda verktyget ansågs vara avgörande faktorer för systemets framgång. Kommunens intresse och initiativ för att anlägga ett röstningssystem var också identifierade som ett bidrag till hög potential för
implementering. De miljömässiga, politiska och rättsliga samt de tekniska aspekterna var även övervägande positiva. Dock kunde ingen specifik slutanvändare bestämmas och
projektet saknar finansiering. Allt tillsammans resulterade i att potentialen för installation av en pilotanläggning i Quelimane i dagsläget är en marginellt hög, men med goda möjligheter att öka potentialen till hög i framtiden.
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Acknowledgements
This project could not have been carried out without the initiative and progressive vision of Mayor Manuel de Araújo, who has acted as a successful driving force for positive
development in Quelimane. We would therefore like to gratefully thank for the opportunity to work on this project and thereby be a part of his visions and work in Quelimane.
The collaboration between the municipality of Quelimane, the Royal Institute of Technology (KTH) and the Mozambican company GreenLight has made this Bachelor Thesis possible, where great gratitude is directed towards David Stoltz and Boris Atanassov. Without their guidance and expertise as official supervisors located in Stockholm and Maputo the design and execution of the project would not have been as successful.
The field study, with multiple interviews, a household survey and several observations in Quelimane, could not have been performed without the great assistance and participation of Arcenio de Araújo and Michel Olofsson. They brought knowledge, support and language skills to the project that was absolutely crucial in order to gather information. A special thanks to Michel Olofsson for doing this voluntarily without own agenda, and to Arcenio de Araújo for prioritizing this project over his own work duties and for his friendship.
Finally, many thanks to; Cecilia Sundberg for the extra work needed in the course as a result of our field study and your guidance, Erika Svensson for believing in the project and your assistance, Catharina Erlich for your involvement in the first stages of the process and getting us in contact with this project, Christina Rudén for your expertise and your voluntary hours spent helping us, Pernilla Zibung for your excellent support and friendship in Maputo and SIDA and ÅForsk for financing and preparing us for this field study.
We would also like to express our gratitude towards all the people who we have interviewed, has answered surveys, accompanied us during the field study, shown us the waste
management in Quelimane, given suggestions for project development or in other ways taken their time to assist and help us with our Bachelor Thesis.
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Table of Content
1. Introduction ... 1
1.1 Purpose ... 2
1.2 Aim ... 2
1.3 Delimitations ... 2
2. Method ... 4
2.1 Literature study ... 4
2.2 Interview study ... 4
2.3 Surveys ... 5
2.4 On-site observations ... 6
2.5 Feasibility assessment tool ... 6
3. Background ... 9
3.1 Mozambique ... 9
3.2 Quelimane ... 10
3.3 Waste-to-energy ... 10
3.4 Anaerobic digestion ... 11
3.4.1 Anaerobic digestion in Africa ... 11
3.5 Biogas security ... 11
4. Current waste management in Quelimane ... 12
5. Local conditions in Quelimane for implementation of an anaerobic digestion system ... 14
5.1 Best suited end product ... 14
5.2 The socio-cultural attitude towards anaerobic digestion ... 14
5.3 Policy and legal ... 16
5.4 Existing and potential funding ... 17
5.4.1 Clean Development Mechanism ... 17
5.4.2 Programa de Desenvolvimento Municipal ... 17
6. Small scale AD plant ... 19
6.1 The plant design ... 20
6.2 The biogas production ... 21
6.2.1 Theoretical calculations for feedstock and end products ... 21
6.2.2 Calculations for pricing of biogas ... 21
6.3 The location of the plant ... 22
6.4 Local market involvement ... 24
6.5 Accessibility of water ... 26
6.6 External design ... 26
6.7 End users ... 26
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6.7.1 Potential future school involvement ... 27
7. Large scale AD plant ... 28
7.1 Key factors for implementation ... 28
7.2 Plant location ... 29
7.3 Cooperation opportunities with existing waste management project ... 29
8. Results ... 31
8.1 Small scale AD plant model ... 31
8.1.1 Funding ... 31
8.1.2 Construction and location ... 31
8.1.3 Waste generators ... 32
8.1.4 Waste segregation and collection ... 32
8.1.5 Waste storage ... 32
8.1.6 Employment ... 32
8.1.7 Water supply ... 33
8.1.8 End products ... 33
8.1.9 End users ... 33
8.2 Potential for implementation of the small scale plant ... 33
8.3 Key factors for large scale AD plant ... 35
9. Conclusion ... 37
10. Discussion ... 38
11. Future work ... 40
Epilogue ... 41
References ... 42
Appendix I ... 44
Appendix II ... 45
Appendix III ... 48
Appendix IV ... 54
Appendix V ... 56
Appendix VI ... 57
Appendix VII... 60
Appendix VIII ... 66
Appendix IX ... 69
Appendix X ... 71
Appendix XI ... 72
Appendix XII... 73
Appendix XIII ... 74
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Appendix XIV ... 75
Appendix XV ... 76
Appendix XVI ... 78
Appendix XVII ... 79
Appendix XVIII ... 80
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List of figures
Figure 1. The different zones in Quelimane. ... 5
Figure 2. Map of Mozambique (United Nations, 1998). ... 9
Figure 3. A disposal site in Quelimane where the waste is disposed outside the container. ... 12
Figure 4. Household survey in Bairro 17 De Septembro. ... 15
Figure 5. The percentage of the different cooking fuels used in Quelimane. ... 15
Figure 6. A balloon digester with weights on top (AfriGadget, 2010)... 19
Figure 7. The design of the balloon plant. (Lüer, 2010). ... 20
Figure 8. The measured area for the small scale AD plant location. ... 23
Figure 9. The small scale AD plant location with the school in the background. ... 24
Figure 10. Gabriel Isequiel Muchave, Matilda Stendahl and Arcenio de Araújo performing an interview at the market. ... 25
Figure 11. Small scale AD plant model. ... 31
Figure 12. The overall feasibility for the six main feasibility criteria. ... 34
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List of tables
Table 1. The average cost for cooking fuel in Quelimane per person and month. ... 16
Table 2. The ratio for the feedstock for the AD digester (Energypedia, 2015). ... 21
Table 3. Theoretical daily production of biogas in AD plant. ... 21
Table 4. The current conditions for a small scale AD plant location. ... 23
Table 5. The quantified feasibility of the six main feasibility criteria... 34
Table 6. The overall potential for implementing an AD system based on the feasibility of the six feasibility criteria. ... 35
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Abbreviations
AD Anaerobic Digestion CBA Cost-Benefit Analysis
CDM Clean Development Mechanism FAT Feasibility Assessment Tool MCDA Multi Criteria Decision Analysis MZN New Mozambican Metical NPV Net Present Value
PPP Public-Private Partnership
PRODEM Programa de Desenvolvimento Municipal USD United States Dollar
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1. Introduction
The generation of municipal solid household waste in developing countries has increased rapidly due to a growing economy, improved standards of living and a rise in consumption, continued urbanization and increasing population levels (Guerrero, Maas, & Hogland, 2013).
This results in an increased pressure to develop new and improved systems for waste management in cities. The responsibilities for waste management often lies with the
municipality, and this results in a challenge since they often lack sufficient financial resources and the appropriate organization and expertise. The complexity and the multidimensionality in the waste management systems adds to the difficulties (Guerrero et al., 2013). Therefore, cities of developing countries often face health and environmental risks related to bad waste management (Lohri, Rodi, & Zurbrügg, 2013).
Economic growth is certainly positive for developing countries, but there is also a back side of technical development and an improved economic situation; the need to produce more energy. Energy is needed to enable the manufacture of goods and furthermore, there is a need to create capital and to provide the residents with infrastructure and services. To achieve this, extraction of resources from the environment is necessary. To continue to grow and develop, sufficient availability of energy will be crucial (Brown et al., 2011).
Mozambique is classified as one of the poorest countries in the world but its economy is currently growing. It has a reasonably stable political climate and there is an increased urbanization. Through comprehensive macroeconomic management, large scale foreign investments and important donor support, the Mozambique’s economy has in the past two decades grown with an annual growth of 7 % in average (World Bank, 2014).
Mozambique has 10 provinces and one capital city. Quelimane is the administrative capital of the province Zambezia, which is located in central Mozambique bordered by Malawi in the west and the Mozambique Channel in the Indian Ocean in the east. Quelimane had, since the independence 1975, fallen to ruin with a flooded cinema, a closed supermarket and the local cathedral abandoned. In December 2011 Manuel de Araújo was appointed mayor and has since then worked hard to transform Quelimane from a downturn town to a developing and thriving city. In 2014, the City of Quelimane, under the leadership of Mayor Manuel de Araújo, won the Drivers of Change Awards in the category Government Award. The motivation for the award given by the judges was that De Araújo "... creates employment, deals with environmental challenges and encourages giving by getting citizens to make the business of development their business" (Drivers of Change, 2014).
To continue the development of Quelimane along these lines, de Araújo wanted to initiate an EcoCity project. The EcoCity concept was coined for the first time by Richard Register in 1987. Register defines an EcoCity to be an “ecologically healthy city”, a city where the ecological footprint is minimized with respect to land and energy use (Register, 1987). One example of an urban subsystem that can be changed with the aim to minimize negative effects on the ecosystem is the management of waste. This can be done by implementing a waste-to- energy system which, while minimizing the waste in the streets, also produces energy. The end product is electricity, heat and/or combustible fuel commodity.
In Quelimane there is a great need for both better waste management and better access to energy for cooking, other than coal. In the current situation the necessary infrastructure for waste collection is lacking and as a result of this health and environmental issues, such as
2 negative effects due to spread of toxic substances, are created (Ahlgren & Gustafsson, 2015).
The health issues associated with preparing food by burning charcoal indoors is a major concern since the smoke produced is very hazardous to human health (Farmer, Nelin, Falvo,
& Wold, 2014).
To start developing the waste management in Quelimane Manuel de Araújo approached the company GreenLight which in turn contacted The Royal Institute of Technology (KTH) in Stockholm, Sweden. GreenLight is a company established in Mozambique working with projects related to environmental technologies to promote a sustainable development. The company has operations in several areas such as renewable energy, waste management and biomass energy (GreenLight, 2010). GreenLight contacted KTH since KTH previously has been involved in a similar project in China and has experience in the area (Stoltz & Shafqat, 2013).
The municipality of Quelimane, KTH and GreenLight have since then started collaboration with the aim to plan and carry out an EcoCity project in Quelimane. As a first step towards this aim, students from KTH performed their Bachelor Thesis in 2015 about sustainable urban development in Quelimane with focus on introducing a waste-to-energy system as a solution.
Regarding the city’s conditions, the conclusion in this study was that anaerobic digestion was best suited for Quelimane (Ahlgren & Gustafsson, 2015). The current project will build on the results of their work and be carried out in Maputo and on-site in Quelimane.
1.1 Purpose
The overall purpose of this investigation is to contribute to the process of improving the waste management as a part of the EcoCity project in Quelimane. Another purpose is that the results from this project can serve as a basis for studies in other cities in developing countries that want to implement an anaerobic digestion system.
1.2 Aim
The aim of the current project is to investigate the potential for implementing an anaerobic digestion (AD) system in Quelimane and examine how such a system can be implemented.
The sub targets to be able to reach the aim are:
1. Analyze and describe the current waste management and waste-to-energy system in Quelimane.
2. Identify relevant actors in Quelimane within waste management.
3. Identify the key factors for implementing an AD system.
4. Make an inventory of threats for implementing an AD system.
5. Create a pilot scale model for the AD system based on local conditions.
6. Investigate inalienable conditions to implement a large scale AD system.
1.3 Delimitations
This project continues previous research done during the spring of 2015 by bachelor students at the Royal Institute of Technology. The goal for their thesis was to determine the waste-to- energy technology best suited based on Quelimane’s conditions. The conclusion was that AD was the most suitable technology, and as a result of this, this report only includes
investigations about AD.
3 The main focus in this project is the pilot scale AD plant since the capacity and current
situation in Quelimane does not allow any advanced technology and are lacking appropriate level of skills, waste management and needed infrastructure for a larger project. The pilot scale AD plant is therefore modelled in as a small scale plant, and is further on referred to as
“the small scale plant”. Furthermore, the development and implementation of a small scale plant is probably to be conducted during the spring of 2017 and therefore closer in time than a large scale plant. Hence, a model for a large scale AD plant is not be carried out; instead the inalienable condition for a large plant will be identified and presented for future development.
The proposed model is theoretical and adapted to the local conditions in Quelimane and is therefore not general. The model includes key factors and identifies the risks and threats for implementation of an AD system, but will not be detailed in terms of technology, economy or environmental impact.
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2. Method
The method of this project consists of:
1. A literature study 2. Interviews
3. Surveys
4. On-site observations
5. Feasibility assessment of the viability of a small scale AD plant in Quelimane 6. Modelling
2.1 Literature study
A literature study has been carried out in order to collect general information about Mozambique and Quelimane, e.g. the economic situation, political climate, social
development and other relevant background for the project. The sources of this study, i.e. the literature that were reviewed, were identified via Science Direct and Primo (KTHB) and Google for finding general background information.
Literature describing the AD technology and the construction of a small scale plant were also identified and reviewed. This information was used for the feasibility assessment and model.
2.2 Interview study
The aim of the interview study was to obtain general understanding of the waste management in Quelimane and gather information for the FAT and model.
On-site in Maputo and Quelimane 28 interviews with actors in the waste management sector and employees at the municipality of Quelimane were performed. These were chosen due to their expertise in the area or involvement in the waste management system.
The interviews were performed semi structured since the technique allows a structured set of question and at the same time permits an open dialog where supplementary information can be gained. It furthermore allows the possibility to follow the respondents thought process.
Finally, it also has the advantage of allowing the interviewer to explain the questions and the relevance behind them in more detail to increase the respondent’s understanding of the issue (Barriball, 1994).
The interview protocols had two parts. The first part consisted of the information that all respondents received prior to the interview. This included an introduction of the project and explanation of the technology. The aim of this was to ensure that all respondents received the same information as well as all the information needed to answer the questions. The second part of the interview protocol was the list of questions.
The interview protocols were modified for each actor listed below:
Maputo:
Embassy of Sweden (1 interview) Quelimane:
Municipality: Department of Waste Management (1 interview)
Municipality: Department of Housing, Infrastructure and Urbanization (1 interview)
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Municipality: Department of Sanitation, Water and Energy (1 interview)
Municipality: Department of Municipal Development Projects (1 interview)
Municipality: The Mayor of Quelimane (1 interview)
Waste collectors (12 interviews)
Merchants at the market (10 interviews)
A more detailed list of the interviews with respondents and dates is presented in Appendix I.
All interviews were performed with one interviewer and one who took notes. The interviews were also recorded. The notes were the primary source of information gathering and the recordings were used to obtain information that was left out in the notes. No transcription was performed and a translator was used when needed.
2.3 Surveys
A survey was designed, shown in Appendix II, and sent to the municipality of Quelimane prior arrival in the city. The survey aimed to gain basic information about the current situation regarding waste management in the city and to work as basis during the literature study as well as helping to gain general understanding upon arrival.
A household survey was also designed; the survey can be found in Appendix III. The survey had two parts. The first part consisted of the information that all respondents received. This included an introduction of the project and explanation of the technology. The aim of this was to ensure that all respondents received the same information as well as all the information needed to answer the questions, similar to the design of the interview protocols described above. The second part included the questions where some were with multiple choice answers. The survey was performed in 30 households located in three different zones in Quelimane; zone 1, 2 and 4, as shown in Figure 1. These zones were selected with help from the municipality and chosen due to the fact that they were:
i. all included in the current waste management system ii. inhabited by people with different income level iii. including both urban and suburban areas
Figure 1. The different zones in Quelimane.
6 The selection of the 30 households was made with the aim to get a sample that was assumed to be representative of the residents in Quelimane.
Each zone has a chief, who is employed by the municipality and functions as an intermediator between the residents in the zone and the municipality. The chief in the zone has in turn secretaries which is responsible for the different neighborhoods within the zone. When performing the household survey, the chiefs of the zones and the secretaries of the chosen neighborhoods were present. The secretaries were the ones who chose the households within the neighborhoods based on the criteria mentioned above.
A translator first explained the project and the AD technology in a simple way and by using illustrative pictures. Then the translator read the survey questions and the multiple choices answers and wrote down the responses from the respondent. This technique was chosen since many people are illiterate and it gave the opportunity to explain when the respondent did not understand the question properly.
2.4 On-site observations
Observations were performed on-site in Quelimane to gain information about the current waste management system. The observations were carried out accompanied by the Councilor of Sanitation, Environment and Climate Change and the Head of Hygiene and Sanitation. The current waste management was examined through observations of the waste collecting points, the waste collecting, the transportation and the final deposit on the dumpsite.
The Councilor of Housing, Infrastructure and Urbanization at the municipality of Quelimane, Yassin Calu Massochua, is in charge of the municipal land in Quelimane. As a representative of the municipality Calu Massochua selected three locations to examine for the small scale plant and one for the large scale plant within the municipality. The locations for the small scale plant were suggested due to its connection to an institution, urban space and/or accessibility.
2.5 Feasibility assessment tool
To determine the feasibility and thereby the potential for the implementation of a small scale AD plant a feasibility assessment tool (FAT) was used (Lohri, Rodić, & Vögeli, 2012).
During the research to find the framework for the analysis, the feasibility assessment tool was found and considered suitable and credible for the project. The tool has the advantage of being extensive and quantifying the qualitative data in order to create results that are easily comprehensible. The tool is based on the four dimensions listed below:
Why?
In this part of the tool the main stakeholders, driving forces and motivations was identified. This includes project initiators, local authorities and funding agencies. This dimension aims to promote cooperation established on clear and explicit expectations and drivers.
Who?
This is a stakeholder analysis with an identification of relevant stakeholders and their role in the AD system. Stakeholders, if any, were to be identified in all the following groups:
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Funding agencies
Waste generators
Legislator and enforcement agencies
Governmental authorities
Future operation and maintenance staff
Site residents (if any)
End-users of AD product
Design and installation specialist
National and international NGOs
Technical/research institutes and universities
All identified stakeholders have been further investigated where their role, driver and means of interventions (how the stakeholder’s influence is expressed in practice) were assessed. Other important matters were the stakeholder’s interest in the AD project as well as their level of control over the AD chain.
What?
The technical aspects and components of the system was identified and described as well as the flows, from the waste generation to the disposal. The AD system was analyzed from a supply chain perspective where main components for a smooth working system were identified in the substrate chain, the AD technology and the product chain.
How?
A Multi Criteria Decision Analysis was used to consider all aspects of the subject divided into six main aspects. The six aspects are described in the FAT and presented below:
1. Technical-operational aspects 2. Environmental aspects
3. Financial-economic aspects 4. Socio-cultural aspects 5. Institutional aspects 6. Policy and legal aspects
For the technical-operational assessment information was gathered from literature data, observations of accessibility of materials and proposed location and interviews with different departments at the municipality in Quelimane. The participating departments were the
Department of Waste Management, Department of Housing, Infrastructure and Urbanization and Department of Sanitation, Water and Energy.
The information for the assessment of the environmental aspects was collected from literature, observations of the proposed location and an interview with the Department of Waste Management at the municipality of Quelimane.
For the financial-economic aspects, information was obtained from interviews with the Embassy of Sweden in Maputo, the mayor of Quelimane and the municipal Department of Municipal Development Projects in Quelimane. In order to perform a cost benefit analysis (CBA), which is a part of the financial-economic aspect, information about costs for
construction, maintenance and all the parts of the modelled system needed to be obtained. The
8 availability and cost for materials was gathered through observations on site and further costs was gathered from literature data and the household survey. The complete CBA is found in Appendix IV.
All information for the socio-cultural assessment was obtained from the household surveys and an interview with the Department of Waste Management in Quelimane.
The information for the institutional aspects was gathered from observations of available materials and an interview with the mayor of Quelimane.
Information for the policy and legal assessment was obtained through documents regarding environmental legislation dealing with waste management and biogas, the renewable energy policy and strategy for Mozambique and e-mail contact with Boris Atanassov.
From the FAT a diagram over the feasibility for each main aspect was constructed based on the results from the dimension How?. This diagram, together with some calculations, showed the potential for the project. Based on information gathered from all parts described above, the modelling of the proposed small scale AD plant was completed. All monetary values, in the model or the CBA, are presented in both New Mozambican Metical (MZN), the currency of Mozambique, and United States Dollar (USD). The conversion between MZN and USD is calculated with exchange rates from the 26th of May, 2016.
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3. Background
In the background section below, general information about Mozambique is presented as well as basic information about the municipality of Quelimane, the waste management and the energy situation in the country.
3.1 Mozambique
Mozambique is located on the east coast of southern Africa and occupies an area of 801,590 km2, a map of Mozambique is shown in Figure 2 (African Development Bank, 2013). The country is inhabited by 25.8 million people with 31.68 % living in urban areas (African Development Bank, 2013) and have an urbanization of 0.8 % (United Nations, 2014). The climate in Mozambique is tropical to subtropical (The World Bank, 2015).
Figure 2. Map of Mozambique (United Nations, 1998).
After almost 500 years as a Portuguese colony Mozambique became independent in 1975.
Until the middle of 1990 the country struggled hard with emigration, droughts, a prolonged civil war and economic dependence on South Africa which altogether prevented the country to develop (The World Bank, 2015). The civil war ended 1992 by an UN-negotiated peace agreement and the country had its first free election in 1994. During the 1990s Mozambique was ranked as the poorest country in the world, but through comprehensive macroeconomic management, large scale foreign investments and important donor support Mozambique’s economy has in the past two decades increased with an annual growth of 7 % on an average (World Bank, 2014).
10 The political climate in Mozambique is currently uncertain since the security situation in parts of Tete-, Manica- and Sofala province has, since the middle of July 2015, been unstable due to armed conflicts between the government (Frelimo) and the opposition party, Renamo (Sveriges Ambassad Maputo, 2016). Despite this the incumbent president Felipe Nyusi is expected to remain throughout his mandate that lasts until 2019 (EIU, 2016).
3.2 Quelimane
Quelimane is the administrative capital of Zambezia and the largest city of the province.
Quelimane is located near the mouth of the river Rio dos Bons Sinais in the central parts of Mozambique. The city consists of 117 km2 of land and is inhabited by 250 000 Mozambicans making it the fourth largest in the country.
Quelimane is currently politically controlled by MDM (Democratic Movement of
Mozambique), an opposition party to the government. In an interview with Andreas Perez Fransius (Appendix V), Perez Fransius explains that this result in less aid from the
government to the whole province of Zambezia compared to provinces that are politically controlled by the currently ruling party, Frelimo.
3.3 Waste-to-energy
Economic development together with population growth and urbanization creates big challenges for African cities when the generation of waste increases and the existing waste management systems are overburdened (Scarlat, Motola, Dallemand, Monforti-Ferrario, &
Mofor, 2015). This leads to a lot of waste being dumped in landfills without utilization of the energetic potential and without recycling or re-use of the material when possible. The
outcome of this is a number of health and environmental problems which especially evolve in developing countries where the landfills’ standards are poor (Karagiannidis, 2012).
Waste management is a complex and cost-intensive public service that involves a lot of challenges, even when organized and operating properly. Therefore, developing countries often spend a high share of their municipalities’ budgets on waste management; in general, from 20 % to 50 % of the total budget. The waste collection often requires 80-90 % of the waste management budget and the service covers only 40-70 % of all the urban solid waste and leaving up to 50% of the population unserved (Scarlat et al., 2015).
To address this, novel strategies are required for solid waste management which local and national authorities can use to reduce the total amount of waste that is disposed in landfills (Scarlat et al., 2015). One strategy to achieve this is to use waste-to-energy plants. The uprising market for waste-to-energy systems around the world has resulted in an increase of treatment capacities globally from 180 to 350 million tons. This development enables a combination of finding sustainable waste disposal solutions with the interest in renewable fuels. Application of such plants furthermore reduces landfills and enhances the utilization of materials and energetic potential (Karagiannidis, 2012).
Waste-to-energy is a process where waste is transformed into energy by conversion of non- recyclable materials through both thermal and non-thermal processes. This can commonly be done by three different techniques; incineration, gasification or anaerobic digestion and the outcome of the processes are normally electricity or heat (CEF - Conserve Energy Future, 2016).
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3.4 Anaerobic digestion
AD is a biological process that produces gas consisting of methane and carbon dioxide, known as biogas, from organic waste. The process takes place in a biogas plant where organic waste is put into an airtight container, a digester, together with various types of bacteria which destroys the biodegradable content. Depending on the feedstock the output gas composition varies but normally it consists of 55% to 75% of methane (California Energy Commission, n.d.).
The process to obtain biogas from organic waste consists of three steps (California Energy Commission, n.d.):
1. Decomposition of organic material where it is broken down to molecules such as sugar.
2. Conversion of the decomposed material to organic acids.
3. Conversion of the acids to methane gas.
The rate of digestion is affected by the process temperature which should be maintained between different degrees according to the design of the AD plant. The biogas extracted from the process can later be used as e.g. cooking fuel or fuel in a generator to obtain electricity (California Energy Commission, n.d.)
3.4.1 Anaerobic digestion in Africa
In Africa a large number of AD plants have been built for single households and such small scale plants can provide the house with gas for lighting and cooking (Ahring, 2003). In developing countries in Africa it is favorable to use the AD technology for a number of reasons. The process is simple, and is in many ways self-controlled. The hot climate in tropical and subtropical areas makes the process suitable and less expensive. The warm ambient air allows construction of anaerobic reactors without external heating (Parawira, 2009).
3.5 Biogas security
There are several risks associated with use of biogas. If biogas is mixed with air at a concentration of 5 % to 15 % it is potentially explosive and flammable. Other risks include poisoning of hydrogen sulfide or asphyxiation. None of these risks are considered a threat and are minimal as long as there are no leaks of biogas in an enclosed area (Westerman, Veal, Cheng, & Zering, n.d.)
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4. Current waste management in Quelimane
The description of the waste management in Quelimane below is based on the information gathered by interviewing the Councilor of Sanitation, Environment and Climate Change, Almeida Colaço, and the Head of Hygiene and Sanitation, Clacia Americo Nofre, the interview notes are shown in Appendix VII. The information has been supplemented by interviews with twelve people working with waste collection in Quelimane, shown in Appendix VIII. Also, a survey was sent via e-mail to the municipality before the field study took place, with questions regarding the current waste management system that also is used as a basis for the description. The survey is found in Appendix II.
In an interview with Almeida Colaço and Clacia Americo Nofre (Appendix VII) the waste management system is described. The municipality has the full responsibility for the current waste management through its associated Municipal Sanitation Company (EMUSA) in collaboration with the Municipal Sanitation Department, hence the only active stakeholder in the waste management. Before 5:30 every morning a team of three superiors from EMUSA goes by car through the city to determine the state at the waste collecting points and identify critical disposal sites. Then, based on their observations, the collecting routes are determined for each vehicle to cover the most critical parts first. This results in different routes every day.
There are containers placed on strategic sites in the city where residents should dispose their waste between 5 pm and 8 pm every day. However, the residents do not respect the time interval for disposal and throw their waste in the containers at any time, which contributes to bad smell and health issues. Also, there are problems associated with residents throwing the waste on the nearby ground when the containers are full, which is visualized in Figure 3.
When the waste is disposed on the ground rather than in the containers the waste collection becomes more difficult and time consuming. This information is compiled from twelve interviews with waste collectors (Appendix VIII).
Figure 3. A disposal site in Quelimane where the waste is disposed outside the container.
13 Depending on the used vehicle the method for collection and disposal of the waste varies:
Truck tippers: the waste removers need to use shovels to get the waste into the flatbed at the collecting points while at the dumpsite the waste is tipped out.
Tractors with a trailer: the waste needs to be shoved both in and out of the trailer.
Lifter: the truck can lift one container up on the trailer and then empty it at the dumpsite. In collaboration with the lifter a forklift is used which operates at the collecting point to put the waste from the ground in to the containers. The waste removers only need to use the shovel to get the surplus waste not collected by the forklift into the containers.
Each truck or tractor has a team consisting of a driver and a number of waste removers, according to the currently working waste collectors (Appendix VIII), and all the waste is disposed at the municipal dumpsite with no further treatment.
In an interview with Colaço and Americo Nofre (Appendix VII), information was gathered about the shifts in the waste management sector in Quelimane. EMUSA has two teams operating during mornings and afternoons respectively. The morning team works from 6 am to 12 pm and the afternoon team starts at 1 pm and end their day at 6 pm. At 10 pm the team of superiors goes by car to check the waste situation again to plan the routes for the afternoon.
Every vehicle has a route that needs to be done by the end of the day.
In the completed survey (Appendix II), the municipality assess that Quelimane generates 90 tons of waste per day which implies in between 3 to 4 kg per household. Furthermore, the municipality estimates that 70 % of the generated waste is organic and the waste collection covers 70 % of the daily generation.
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5. Local conditions in Quelimane for implementation of an anaerobic digestion system
The people of Quelimane have very limited knowledge in waste-to-energy and have therefore no current activities related to any waste-to-energy solution. The current waste management lack important resources and structure which contributes to the big challenge of implementing an AD system in the city (Ahlgren & Gustafsson, 2015).
In an interview with the incumbent mayor of Quelimane (Appendix VI), de Araújo stated that he initiated this AD project to improve the current waste management as well as the city’s economy and to reduce the ecological footprint from the residents in the city.
To implement an AD system a number of key factors have been identified through interviews, observations and a literature study.
5.1 Best suited end product
The produced biogas from AD can either be consumed in its current form, as gas for cooking, or go through a generator in order to produce electricity. The chosen end product for an AD plant in Quelimane was biogas for cooking due to the following reasons, arisen during an interview with Almeida Colaço and Clacia Americo Nofre:
Most residents in the urban area of Quelimane already use gas for cooking and are familiar with the method and have the facilities to use the biogas (though a biogas burner should be installed in order to improve the heat efficiency from the biogas).
The current cooking gas is transported in trucks from Maputo and the transportation cost is eliminated with local production of biogas. This will result in cheaper gas that may have the potential to compete with charcoal, which is the most popular cooking fuel in Quelimane today. That would bring health and usage benefits.
The demand of gas is higher than the supply and therefore production of biogas will naturally contribute to a more stabilized supply-demand relation.
The demand of coal is higher than the supply since the availability of wood to produce coal in the vicinity of the town decreases. A change in the use of cooking fuel, from coal to gas, would hence lead to reduction of deforestation.
If electricity were to be produced a new grid would need to be built within the municipality since Electricidade de Mozambique, E.P owns the national grid.
Since there is monopoly on the electricity market it is complicated to get the rights to produce electricity.
5.2 The socio-cultural attitude towards anaerobic digestion
The information in this section was gathered through the household survey in Quelimane summarized in Appendix III. An overview and calculations of the cost for cooking fuel in households are shown in Appendix IX. Also, additional observations have been carried out in order to complement the information from the household survey. Due to bureaucracy the household study was performed by the authors accompanied by three or four people
15 representing the municipality administration. The household survey was read out loud to the respondent by a translator and each interview was conducted in a similar manner as the one shown in Figure 4.
Figure 4. Household survey in Bairro 17 De Septembro.
The residents of Quelimane are using charcoal, gas, wood, electricity and fusion of alcohol as cooking fuel, were charcoal is the fuel most commonly used, visualized in Figure 5.
Figure 5. The percentage of the different cooking fuels used in Quelimane.
The use of gas and electricity is identified in the urban area of Quelimane and wood is more frequently used as cooking fuel in the more sub-urban areas. The gas currently used for cooking is butane or propane. Charcoal is included in both the urban and suburban areas’
97%
17% 13% 10%
0% 3%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Charcoal Gas Wood Electricity Alcohol fusion
Percentage of population
Cooking fuel
Cooking fuels in Quelimane
16 cooking habits; it is used either as the main fuel or as a complement to gas and/or electricity.
The average cost for cooking fuel in Quelimane is shown in Table 1.
Table 1. The average cost for cooking fuel in Quelimane per person and month.
Zone 1 Zone 2 Zone 4 Total
Cost [USD] 3.1 2.0 1.8 2.3
Cost [MZN] 170 109 102 127
The low price and high accessibility is the main reason for the charcoals’ popularity as a cooking fuel. People consider they do not have a choice in what cooking fuel they can use due to the price difference to other cooking fuels. Other benefits with charcoal that was raised was that it is a better alternative in terms of generated smoke amount than wood and that you can cook both outside and indoors. The disadvantages of charcoal that was identified by the residents were mainly that themselves, their clothes and their house becomes dirty as a result of cooking with charcoal. High smoke generation, production of ashes and problems
associated with the charcoals toxic properties were also voiced concerns.
A sixth of the residents in Quelimane are using gas for cooking. A fear that was identified was the safety of application of gas. Even though the residents have a mainly positive attitude towards the safety of the technology, people raised concerns about the safety of the gas. There is an overall distress in some areas that the gas is very explosive and is as a result of this people is afraid to use it.
The attitude towards using domestic waste in order to produce cooking fuel in Quelimane is mainly positive. The population is willing to segregate their organic and inorganic waste in the households, but the level of willingness to segregate waste is marginally higher among the residents if they were to be compensated with a small amount of money in return. There is also a high willingness to use biogas for cooking, but both the safety of application and the price for the gas was voiced concerns. About two thirds of the population in Quelimane has their own farming outside their housing and therefore the willingness to use fertilizer from an AD plant for own usage or others is high.
Another factor to take in to consideration is that people are making their own charcoal as a part of their livelihood, and are therefore not interested in using biogas for cooking. The produced charcoal is partly used for own cooking purposes and partly sold for 0.09 or 0.18 USD (5 or 10 MZN) per bag. These people would not be able to sell charcoal if there were a change from charcoal to gas, and as a result of this, they would lose income.
The people of Quelimane have in general a very positive attitude towards this project. Even so, a need to explain the benefits for the community is identified in order for them to
segregate the waste for free. Also, the price of the biogas is considered to be the main barrier in terms of change in cooking fuel.
5.3 Policy and legal
In order to investigate the Mozambican policies, laws, standards and regulations relevant to AD, the ”Renewable Energy Policy and Strategy for Mozambique 2011-2025”, published by Ministério da Energia (n.d.) and the environment legislation regarding waste management, biomass projects and residue disposal, published by Conselho de Ministros (2006) were obtained and reviewed. Then, in order to understand and interpret the information, Boris
17 Atanassov, founder of GreenLight, was asked to fill in the feasibility criteria for policy and legal in the FAT. His answers are presented in Appendix XVI.
The laws and regulations are only available in Portuguese, and due to the fact that Atanassov works in the energy sector in Mozambique he was considered suitable to answer these questions. Further investigations regarding policies and regulations relevant to AD were not performed.
The current national and international policies regarding AD was considered “neutral” and the current national and international laws, standards and regulations regarding AD “supportive”, according to the FAT. Current enforcement practices of laws, standards and regulations for the AD project were determined to “neutral”.
The chances that supportive policies, legislation, standards and regulations for AD will be established, enacted and enforced in the near future was identified as “medium“ on a scale of high, medium and low.
5.4 Existing and potential funding
The municipality of Quelimane does not have any existing sources of funds in order to implement an AD system and there is currently no plan for the funding of the pilot project.
The National Energy Fund, the French Development Agency and other international funds are according to the mayor de Araújo in an interview (Appendix VI) sources that need to be examined for further work. Other identified funding possibilities for the large and small scale AD plant are Clean Development Mechanism (CDM) and Programa de Desenvolvimento Municipal (PRODEM).
5.4.1 Clean Development Mechanism
The Clean Development Mechanism (CDM) is a tool under the United Nations Framework Convention on Climate Change (UNFCCC) and aims to reduce greenhouse gas emissions globally. CDM aims at letting industrialized countries to reduce their carbon emissions by invest in projects that reduce emissions in developing countries. If an industrialized country sponsor or engage in projects that aim to reduce carbon emissions in developing countries the industrialized country earns carbon credits. This system functions as an approach for
developed country to reach their emission targets as well as increase the access for developing countries to new technology and achieving sustainable development (Zaman, Hughes, & Llp, 2012).
Waste handling and disposal is a category of projects that can be funded by CDM. The production of biogas from the waste stream extracts methane, which is a greenhouse gas 20 times stronger than carbon dioxide, and in that way reduces its Global Warming Potential (GWP). Moreover, by decreasing the amount of solid municipal waste at the landfill (or dumpsite) by producing biogas, the generation of methane due to natural anaerobic
decomposition at the disposal site reduces (“Guidebook to Financing CDM Projects,” n.d.).
5.4.2 Programa de Desenvolvimento Municipal
PRODEM is a project developed in collaboration between the Swedish, Danish, Irish and Swiss embassy in Mozambique. The project is aiming to support sustainable urban development in 26 municipalities in the central and northern regions of Mozambique and might, according to Andreas Perez Fransius, be a part of the funding for the AD project in
18 Quelimane. Further investigation was not performed due to the uncertainties regarding
the projects design and execution and hence the ability to obtain funding.
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6. Small scale AD plant
In order to successfully implement a small scale AD plant in Quelimane, it is essential that the technology is inexpensive, easy to construct and maintain as well as insensitive to variation in substrates and hot climate. These factors were identified through observations on site. The plant type that was considered best for the local conditions was a balloon plant since it was the technology that met the desired criteria the most compared to other technologies.
The balloon plant consists of a rubber or plastic bag that includes both the digester and the gas holder since the gas is naturally stored in the upper part of the bag. Since the bag needs to be UV-resistant, tolerant to weather and stabile, special material is required and synthetic caoutchouc or reinforced plastic is recommended. The outlet and inlet tubes are attached on the skin of the bag and to increase the gas pressure weights can be added on top of the bag as shown in Figure 6. To prevent damage on the skin due to high gas pressure safety valves are required in the design. The useful lifespan of the balloon plant is between 2 and 5 years (Kossmann et al., n.d.).
Figure 6. A balloon digester with weights on top (AfriGadget, 2010).
There are several advantages identified with the balloon technology in order to be suitable to local conditions. The cost for construction and monitoring are low and the maintenance and cleaning is uncomplicated. Also, the construction and installation is suitable for use in areas with high water table and the required digester temperature is high which suites tropical conditions. Another advantage is that difficult substrates can be used in this type of digester (Kossmann et al., n.d.).
The disadvantages of the balloon plant are mainly the short lifespan of 2-5 years and the fact that the bag is easily damaged. A problem associated with the reduced quality of the material is that local craftsmen rarely have the competence to repair a damaged plant. Other problems that are identified are the gas pressure is relatively low and the construction can therefore require pumps and the fact that scum cannot be removed when operating. The small plant does not generate local employment opportunities (Kossmann et al., n.d.).
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6.1 The plant design
For the balloon plant functioning as the small scale AD plant in Quelimane, the chosen design for the model is a Low-Cost Polyethylene Tube Digester, a design that have been successfully used in a number of countries in Central and South America. During an e-mail conversation with Dr. Tico Cohen, CEO and founder at Bioenergy Works BV (Appendix XI), Dr. Cohen stated that even though the substrate used in the implemented digesters of this design were animal manure, organic waste from households can be used as well and will produce more gas. The model is designed to supply biogas directly to a biogas stove. The design for the digester is shown in Figure 7.
Figure 7. The design of the balloon plant. (Lüer, 2010).
The required materials to build the digester were obtained from the Installation manual for Low-Cost Polyethylene Tube Digesters. The manual is originally written by Jaime Marti Herrero in Spanish (Herrero, 2008), but the manual used in this report is the English translation, done by Marc Lüer (Lüer, 2010). In order to determine if the materials were locally available three hardware stores were visited in Quelimane. A list of the materials with corresponding pictures was given to the shop assistant to examine in each store and if the material was available the price was obtained. The materials that was not available in
Quelimane was examined in the same manner in Maputo, and if not found there, the material was found on the internet. The only product not found in any of the six hardware stores visited in Quelimane and Maputo was, according to the employees’ at all three hardware stores in Maputo, nevertheless available nationally. The results are summarized in Appendix XII.
Since one concern with the balloon plant is the vulnerability and lack of competence to repair damage this simple design was chosen where most of the parts are available locally and therefore easy to access when needed for a repair. The design is adapted to the competence in developing countries and easy and fast to build and repair following the manual (Lüer, 2010).
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6.2 The biogas production
In order to determine the produced quantity of biogas in the balloon digester another AD plant technology was required for the calculations. This technology is developed by ARTI
(Appropriate Rural Technology Institute) and is a successful small scale AD plant which uses waste food as feedstock. For the balloon AD plant technology, there is only available data for animal manure as feedstock and not waste food. Due to this, calculation has been performed for the ARTI technology due to its similarity in the feedstock, rather than performance of technology. Therefore, data for the ARTI technology further on is assumed to represent the suggested balloon technology. The presented ratio of the input and output in the ARTI Biogas system is shown in Table 2.
Table 2. The ratio for the feedstock for the AD digester (Energypedia, 2015).
Waste food input Water input Digestate output Biogas output
[kg] [m3] [m3] [kg]
AD digester
1 0.01 0.01 0.25
[m3]
The reaction for biogas production is completed in 24 hours when the digester is working properly (Energypedia, 2015).
6.2.1 Theoretical calculations for feedstock and end products
The entire volume of the suggested balloon plant is 3.6 m3, where 2.7 m3 is liquid volume and 0.9 m3 is gas volume (Lüer, 2010). This results in an input of 2.7 kg organic food waste and 27.2 liters of water as well as an output of 27.2 liter digestate, according to Table 2.
Biogas has a density of 1.15 kg/m3 (Jørgensen, 2009) and 1 m3 biogas is equivalent to cooking a total of 15-18 meals in (Kristoferson, 1991). The daily production of biogas in the small scale AD plant is therefore calculated as in Equation (1), (2) and (3) and presented in Table 3.
2.7 𝑘𝑔 𝑑𝑟𝑦 𝑚𝑎𝑡𝑡𝑒𝑟 ∙ 0.25𝑑𝑟𝑦 𝑚𝑎𝑡𝑡𝑒𝑟𝑘𝑔 𝑏𝑖𝑜𝑔𝑎𝑠 = 0.68 𝑘𝑔 𝑏𝑖𝑜𝑔𝑎𝑠 (1)
0.68 𝑘𝑔 𝑏𝑖𝑜𝑔𝑎𝑠 1.15𝑘𝑔 𝑏𝑖𝑜𝑔𝑎𝑠
𝑚3
= 0.59 𝑚3 𝑏𝑖𝑜𝑔𝑎𝑠 (2)
0.59 𝑚3∙ 15 − 18𝑚𝑒𝑎𝑙𝑠𝑚3 = 8.85 − 10.62 𝑚𝑒𝑎𝑙𝑠 (3)
Table 3. Theoretical daily production of biogas in AD plant.
[kg] [m3] Meals
Daily produced biogas in digester 0.7 0.6 8.9–10.6 6.2.2 Calculations for pricing of biogas
In order to be competitive on the market the gas should be sold for a similar price as the average household cost for cooking fuel, and preferable the gas should be priced in such a way that it can compete with charcoal. The average cost for cooking fuel in Quelimane per person and month is 2.3 USD (127 MZN) and is presented in Table 1.
22 The digester produces 20.4 kg of biogas in one month which is enough to prepare 318 meals.
For an average urban household in a developing country this can supply one person with food in 159 days or 5.3 people with food for one month. Based on this, and the assumption that the pricing should be set at the average cost for cooking fuel, the price for the monthly amount of 20.4 kg biogas is 12.2 USD (674 MZN). The calculations are visualized in Appendix XIII.
6.3 The location of the plant
Through observations and oral communication with Yassin Calu Massochua and Michel Olofsson (Calu Massochua, 2016a; Olofsson, 2016a) the criteria for an ideal location was determined. The location for the small scale AD plant is ideally located in an urban space, in connection to an institution and in a space with high accessibility. Also, the plant should preferable be located in a short distance from where organic waste is generated.
The urban space is considered important due to the viability to transport the organic waste to the plant, maintenance and the distribution of the end product. Also, the interest and spread of knowledge of AD will have a greater impact if the plant is located in an area where there is a lot of human activity.
The benefits of connecting the small scale plant to an institution are that the institution could work as end users of the biogas. There is a possibility to create a self-sufficient system, where the institution uses their organic waste as feedstock, maintain the plant and finally act as end- users of the produced biogas and/or digestate. If a school is the chosen institution there is an added benefit of involving children and young people, and in that way impacts their attitude towards waste management, waste segregation and sustainable energy production.
The main objective in implementing the pilot project is to create a plant that is easily
constructed and maintained with a high level of function and replicability. If the pilot project is considered successful, the probability that a second small scale plant would be
implemented increase, according to Manuel de Araújo in an interview (Appendix VI). A second small scale AD plant is considered a step towards implementing a large scale AD plant in order to provide the entire or a major part of the city with biogas.
The Councilor of Housing, Infrastructure and Urbanization at the municipality of Quelimane, Yassin Calu Massochua, is in charge of the municipal land in Quelimane. As a representative of the municipality Calu Massochua selected three locations for the small scale plant within the municipality with regard of the ideal requests. Since the municipality is the initiator of this project, with no other active actors, the location space needs to be owned by the municipality and available for construction. The following information about the suggested locations is from oral communication with Yassin Calu Massochua.
The first proposed location for the small scale plant is located three kilometers outside the city center, next to a fisherman’s village. The assigned space is located on a small height where the water level raises during the rainy seasons. In order to construct a pilot plant, the proposed land needs to be sanded and leveled. The municipality has a future plan to create a fish market in connection to the proposed space which would generate a lot of organic waste and create a demand for energy to provide cooling.
The second site is located in a rural area called Bairro-Icidua, five kilometers outside the city center. The proposed space is located in a village, in connection to a school. The school cooks
