THE SEWCHAR CONCEPT:
AN INTERDISCIPLINARY APPROACH
A case study report on the contribution of sewchar to sustainable development
in Nairobi County, Kenya
Jeroen Gerdes (5634512) Marijn Gülpen (10575243) Sybrig Simkje Smit (10536418) Johnny Vogel (10683836)
Date: ... April 25, 2016
University: ... University of Amsterdam Study: ... Future Planet Studies Course: ... Interdisciplinary Project Coordinator: ... J. C. Tromp
Tutor: ... K. H. van der Gaast Expert: ... C. F. Rammelt Amount of words: ... 7859
Abstract
Human excreta is still waiting for recycling options. Sewchar, a fertilizer made from human excreta by hydrothermal carbonisation (HTC), has been put forward as a sustainable solution to tackle problems concerning sanitation and human health, environmental degradation (pollution) and food production in third world countries. This paper provides insights from an interdisciplinary case study, to what extend an implementation of the ‘sewchar concept’ can contribute to sustainable development in Nairobi county. In order to research an implementation of the sewchar concept on its sustainability, the steps of the production chain of sewchar were defined; (1) excreta collection, (2) transport, (3) processing and (4) soil application. The four production chains have been tested on the four pillars of sustainability, as defined by Haughton (1999): (1) futurity, (2) equity, (3) participation and (4) biodiversity. This research argues that the sewchar concept may have a very positive effect on futurity, a neutral effect on equity, an uncertain effect on participation and a positive effect on biodiversity. Future research and small-scale trials are recommended to create a more complete understanding of the contribution of the sewchar concept to sustainable development.
Index
Introduction... 4
Theoretical framework ... 6
Methods... 9
Results ... 12
Discussion & recommendations ... 20
Conclusion... 22
References ... 24
Introduction
After the decolonization of Kenya in 1963 urbanization levels increased dramatically (Fox, 1992). The rapid unplanned growth of the city has led to informal settlements where people have poor access to sanitation facilities (Thieme, 2013). This limited access to proper sanitation facilities increases the risk of outbreaks of waterborne diseases because of a lack of personal hygiene (Kiulia et al, 2010). Another problem caused by the absence of sanitation facilities is that human excreta is disposed in the environment without any form of treatment. Micro-organisms responsible for diseases like cholera, typhoid and diarrhea originate from faeces of humans and animals and cause health problems when they enter the water cycle (Ashbolt, 2004). In some areas of Nairobi, one toilet is available per eighty-five households and this number must be reduced (Corburn & Hildebrand, 2015). Besides poor sanitation, Kenya is facing another problemen of great concern: food insecurity (Oluoko-Odingo, 2011). Common modern land use practices in Kenya show an exponential loss of soil quality over time which enhances desertification and decreases the potential yield (Kimentu et al., 2008; Lal, 2006). Application of sewchar to agricultural lands in Kenya helps to avoid desertification by maintaining a higher soil quality.
The sewchar concept has been proposed by Breulmann, van Afferden & Fühner (2015) as a potential integral sustainable solution for several problems which developing countries are facing. The sewchar concept is an innovative proposal for a production chain were human excreta is converted to an organic fertilizer. This concept might have a high potential of contributing to sustainable development in developing countries because this concept offers sanitation facilities, treatment of human excreta and a fertilizer which may lead to increasing agricultural yields. Besides that, does the production of sewchar create job positions for local people. This study is a first attempt to test whether the sewchar concept may contribute to sustainable development in a Sub-Saharan region. In order to evaluate this, the Nairobi County is chosen as a case study area. Nairobi is a fast growing city were urban planning is often lacking leading to poor facilities. Besides that, many people are unemployed and job possibilities are low (Thieme, 2013). Environmental concerns for Nairobi are air pollution by traffic and water pollution by the entering of untreated wastewater in rivers like the Athi River (Gateri et al., 2013; Marwick et al. 2014). For such problems implementing the sewchar concept might be an improvement but as this concept has never been implemented before, very little is known about the possible contribution of the sewchar concept to the sustainable development of Nairobi. The main research question addressed in this paper therefore is: “To what extent can the implementation of the sewchar concept contribute to sustainable
development in Nairobi County?”.
In order to investigate whether the implementation of the sewchar concept contributes to sustainable development in Western Kenya, an interdisciplinary approach is chosen. Researchers from various disciplines, in both social and natural sciecnes, worked together to investigate whether the sewchar concept can be a form of sustainable development for developing countries. The choice for an interdisciplinary research is based on the assumption that implementing the sewchar concept leads to
modifications of the current system Nairobi County and that these modifications will have an effect on both the people and the environment in Nairobi County. Following the definition of sustainable development by Haughton (1999), development can only be defined as sustainable if development leads to an improvement of the four pillars of sustainable development. These pillars are futurity, equity, participation and biodiversity.
This paper firstly explains the concepts used in this research in the theoretical framework section. The concepts explained are the sewchar concept and sustainable development. The used research methods are assessed in the methodology section, together with an explanation on the integrative research techniques. In addition, there is a brief description of Nairobi County. Subsequently, the results are presented, in which the four pillars of sustainable development and four steps within the production chain of sewchar form a framework. Shortcomings and uncertainties are presented in the discussion, combined with recommendations for future research. A short recap of the results can be found in the conclusion, supported by a graphic visualisation, in order to be able to evaluate the desirability of the sewchar concept in Nairobi County.
This research is a first investigation to assess the constraints for sustainable development for a newly developed concept. The first description of Fühner et al. (2014) has only mentioned some of the benefits of sewchar concept, but scientific research on the sewchar concept has not been conducted so far. A critical reflection from both both natural and social sciences might provide a more complete overview of the potential contribution of implementing the sewchar concept to the sustainable development of an urban region of Sub-Saharan Africa.
Theoretical Framework
This section explains two key concepts of this research namely the sewchar concept and its production chain and sustainable development. These concepts are the backbone of this interdisciplinary research.
The sewchar concept
The sewchar concept was introduced in the scientific journal Nature by Breulmann et al. in 2015. They presented the sewchar concept as a potential sustainable solution to several problems which developing countries are facing. The sewchar concept is based on the idea of using human excreta as a source for biochar production. The produced biochar - sewchar in this paper - can be used as a high quality soil amendment. The sewchar concept offers an additional approach to obtain biochar where human excreta serve as a carbon source. Biochar is created when biomass is pyrolysed, which means that the biomass is heated in the absence of or with limited oxygen to temperatures exceeding 250 ºC. This process creates a coal-like product which can be used as a soil amendment (Lehmann & Joseph, 2015). Where the biochar concept is based on input of plant biomass, sewchar is produced from carbonaceous material from human waste which does not face relevant competition for alternative utilization (Breulmann et al., 2015).
Using human excreta to produce sewchar might offset the need for the installation of expensive infrastructure for conventional sewage treatment. Therefore, the sewchar concept offers a sustainable and innovative way to extract human waste from being disposed at the environment. Currently, human waste and excreta contribute significantly to environmental pollution because the waste enters the environment untreated, causing a risk to both human and environmental health by accumulation of organic and inorganic contaminants (Marwick et al. 2014).
The production chain of the sewchar concept
As stated before, the sewchar concept, as suggested by Breulmann et al. (2015), is a possible solution for sanitation problems in developing countries, but it is still a new concept and little research has yet been conducted. Therefore, practical models for the implementation and execution are not yet available, and should be adjusted per situation and region. For this case study in Nairobi County, a model is made from the production chain of the sewchar concept (Figure 1). It is an adapted model, inspired by the ‘The Sanergy Model’ from Sanergy. This organisation builds on healthy, prosperous communities by making hygienic sanitation affordable and accessible (Sanergy, 2016).
Figure 1 The production chain of the sewchar concept, an adaptation of ‘The Sanergy model’
(Source: http://saner.gy/our-work/the-sanergy-model)
For this case study the production chain of the sewchar concept is divided in four chains: excreta collection, transport, processing and soil application. The first step in the chain, excreta collection, is adapted from the way Sanergy collects human excreta. Their idea is that local entrepreneurs purchase toilet boxes and manage these low-cost, high quality hygienic sanitation facilities with collection cartridges. They become franchise partners of the organisation. The operators are trained and equipped to remove the filled cartridges and replace them with clean, empty cartridges. The operators are responsible to bring the filled cartridges at nearby local strategic collection points, by wheelbarrow, handcart, and/or truck. The second part of the production chain is transport. From the strategic collection points the cartridges are transported by trucks on a daily basis to the processing facilities. The third step is the processing of the excreta. At centralized facilities human excreta are converted into biochar/sewchar by hydrothermal carbonisation. The end product is high-quality organic fertilizers. The fourth step is the application of the sewchar on agricultural lands. The sewchar may be sold by entrepreneurs or provided by non-governmental institutions.
Sustainable development
Sustainable development is a frequently contested concept with a wide range of meanings (Giddings, Hopwood & O’brien, 2002). The classic definition was set up by the Brundtland report: “meeting the needs of the present without compromising the ability of future generations to meet their needs” (Giddings et al., 2002, p. 188). As may be imagined, this definition leaves room for free interpretation. In addition, it leads to conflict between concepts such as economic growth, social equity, the environment and human needs (Giddings et al., 2002). When separated, one may assume that the factors economy, society and environment have the ability to fill in for each other. For example, economic factors cannot replace
ecosystems. In addition, the focus on the fundamental connections between the factors may be lost. Therefore, Giddings et al. (2002) proposed an approach to sustainable development in which there is no separation of the three factors society, economy and environment. By breaking down the boundaries between society, economy and environment, opportunities for interdisciplinary, interconnected analyses are created.
Naturally, when deleting the boundaries between economic, societal and environmental factors, there is a risk of an incoherent analysis. Therefore, it is based on four principles: futurity, equity, participation and biodiversity (Haughton. 1999 & Giddings et al., 2002). “These principles (…) would
move society beyond present approaches based on monetary cost/benefit analysis or a utilitarian view that can justify the suffering of some by the benefits of others” (Giddings et al., 2002, p. 194).
Haughton (1999) has defined the four principles of sustainable development. The principle of futurity is the closest link to the Brundtland-definition of sustainable development and can also defined as
inter-generational equity. This means that human activities of the present may not affect future
generations negatively. The second principle, equity, is in this context more related to contemporary social justice and therefore seeks to overcome the current factors influencing (in)justice, not only by redistributive measures. It also entails geographical equity, which is also known as transfrontier
responsibility. This means that local policies should be geared at both local and global (environmental)
issues and therefore localities are as important as worldwide problems. This is closely linked to the third principle of sustainable development: participation. This principle holds that systems should be conducted in order to ensure that all people are treated openly and fairly. This also means that people need a certain framework for the political decision-making in which they can be consulted. The first three principles of sustainable development are quite anthropocentric, but the value of ecosystems should not be forgotten. This is adopted in inter-species equity, which is converted to biodiversity by Giddings et al. (2002). It does not point out the moral equivalence of humans with other lifeforms, but it underlines the importance of biodiversity and certain rights within nature.
There are also other definitions of sustainable development. Jabareen (2008) provides an overview of different approaches, in which the approach of Haughton is also mentioned. Jabareen states that many scholars, environmentalists and governments agree that sustainability could be achieved through the effective balancing of social, environmental and economical objectives. In the methods and discussion sections is explained why the latter is not touched upon and what the critics are on the definition of Haughton (1999).
Methods
Site description
Kenya is ranked ninth in terms of GDP in African nations, the nation faces food insecurity and poverty. Agriculture contributes to 24% of Kenyan GDP and circa 80% of Kenya’s population works in the agricultural sector (Oluoko-Odingo, 2009). A strong relation between poverty and food insecurity has been proposed (Oluoke-Odingo, 2011). The underlying mechanisms responsible for food insecurity are low agricultural productivity, lack of marketing, unemployment and low wages (Oluoko-Odingo, 2009). Besides that, an estimated 70% of all Kenyan households lacks access to improved sanitation (Simiya, 2015). Sanitation is an important element of poverty reduction because diseases related to human excreta affect human well-being and their productivity (Ashbolt, 2004). This case study provides insights to what extent an implementation
of the sewchar concept in Nairobi county can contribute to the sustainable development of the region. Nairobi County was chosen as the location for this case study based on eight criteria formulated by the authors. These criteria were: located in a developing country, poorly developed sanitation networks, food insecurity, degraded water quality and degraded soil quality, a large urban population, presence of agricultural land and a type of water body within the region. Nairobi County is a region that matches these eight points of criteria (Oluoke-Odingo, 2009 ; Simiya, 2015 ; Wang et al., 2012; Marwick et al. 2014).
Accessibility of data is a problem for research in developing countries. One advantage of conducting research in Kenya is that English is commonly spoken within Kenya. This increases the accessibility of data in Kenya (Kioko & Muthwii, 2001). In addition to that, an organization named Sanergy develops accessible and affordable sanitation facilities in the study area. Information provided by this organization has been very valuable for this research.
Research technique: from a disciplinary to an interdisciplinary research
This interdisciplinary research started from a disciplinary perspective in order to acquire specialist knowledge about relevant theories and concepts. Four disciplinary research reviews were written: two from an earth scientific perspective, one from the perspective of a human geographer and one from a biological perspective. The Earth Science discipline was divided in two specialisations: one focussing on the agricultural use of sewchar whereas the other focussed on the production of sewchar. Individual literature review by each of the specialists served as the backbone for interdisciplinary research. The concepts from the disciplinary results were compared and linked together to find similarities and contradictions during brainstorm sessions. The concept sustainable development as described by Haughton (1999) was used to create common ground between social and natural sciences because both are represented in the four pillars of sustainable development. Eventually, this research made use of the organization technique, which “creates common ground by clarifying how certain phenomena interact and mapping the causal relationships” (Repko, 2012. p. 346). With this technique an integrative model (Appendix A) was created to evaluate the sewchar concept on the basis of sustainable development in which all three disciplines came together. This integrative model gave an overview to discuss the influence of every chain of the sewchar concept on all pillars of sustainable development described by Haughton (1999). As elaborated in the theoretical framework, the production chain of sewchar is separated in four steps: excreta collection, transport, processing and soil application. These four steps of the sewchar production chain will be evaluated on and linked to the four pillars of sustainable development: futurity, equity, participation and biodiversity. The initial integrative model has been modified during the research due to new insights and lack of information.
Choices for integrative model
As explained above, an integrative model was conducted by linking the four principles of sustainable development to the four steps in the chain of the sewchar concept. Since the different steps of the chain have significantly different impacts on human and environmental well-being, this research chose to evaluate the effect of the sewchar concept on sustainable development per production step. In addition, the weight of some impacts within the chain may differ, which comes across best if separated from each other. This is also the case for the principles of sustainable development, in which there is a time-related aspect as well, since it has a great focus on effects in the future. By presenting the sustainable development principles separately, but linked to the steps of the sewchar concept, different weights of the results can be underlined. Also, the amount of uncertainties within the results can be clearly presented. As shortly mentioned in the theoretical framework, there are many other definitions on sustainable development. However, the definition presented by Haughton (1999) and further explained by Giddings et al. (2002) has been chosen for its ideological stance. Since the sewchar concept has not been used intensively yet, a more technical approach, such as a cost-benefit analysis, seemed hasty and ill-considered. To clear the path for future research in which the technical and applied definitions can be
incorporated, the philosophical, ideological definition of sustainable development, besides its shortcomings demonstrated in the discussion, seemed proper.
Data collection & quantifying data
Scientific literature gathered in the disciplinary literature reviews provided the basic data available in this research. Data available on the website of the company Sanergy served as a source of inspiration for the sewchar production chain. The information provided by the website was of substantial value for the linkage between the region and the concept that has significant similarities with the sewchar concept. However, because the data from the Sanergy webpage was written by the Sanergy company itself, values and perspectives obtained from the webpage should be interpreted with a critical stance. The results are, where possible, based on field-studies in the Nairobi region or on studies regarding the region of Eastern Africa. In some occasions, data was used discussing developing countries in general. Finally a value was given to each of the pillars of sustainable development. Possible values were very positive, positive, neutral, negative, very negative or uncertain.
Results
This section discusses how the steps of the sewchar production chain contribute to sustainable development. This can either be very negative, negative, neutral, positive, very positive or uncertain. By assessing each step of the production chain from the perspective of each of the four pillars of sustainable development, the question how the sewchar concept can contribute to sustainable development in Nairobi County, Kenya, can be answered.
Futurity Equity Participation Biodiversity
Collection • Pathogen removal (+) • (Improved) water quality (+) • Human health (+) • Bottom up solution (+) • Local purchases (+) • Risk of monopolies (-) • Pathogen removal (+) • Health quality (+) • Employment (?) • Sanitation- entrepreneur projects (+) • Decrease nitrogen levels (+) • Decrease hypoxia (+) • Decrease eutrophication (+) Transport • Emissions (-) • Road development (+) • Employment (+) • Risk of monopolies (-) • Employment (?) • Emissions (-) • Habitat fragmentation (-) • Road kills (-) • Traffic noise (-) Process • Recycling excreta (+) • Renewable energy (+) • High investment costs (?) • Employment (?) • Stakeholder investment (?) • Undesired by-products (-) Application • Soil quality (+) • Water savings (+) • Desertification (+) • Food security (+) • Employment (±) • Market access of farmers (±) • Fertilizer market competition (?) • Increase soil biota diversity (+) • Reduce recovery time after agricultural activities (+)
Figure 3: Overview of the integrative model with the results and most important concepts. (+) is a positive impact,
(-) is a negative impact, (±) is a neutral impact and (?) is an unknown impact.
Futurity
The principle of futurity within the used definition of sustainable development (Haughton, 1999) focusses on future generations. The principle is based upon the idea that human activities of the present should not affect future generations in a negative way. To achieve sustainable development with the sewchar concept in Kenya County, the sewchar production chain should not harm people and the environment in the future. Ideally, future generations will benefit from this concept. This section shows the results of the
Sewchar Concept Sustainable
sewchar concept on the sustainable development pillar futurity. The effects of present human activities on futurity are described for the excreta collection, transport, processing and soil application.
When implementing the sewchar concept, human excreta will be collected in Nairobi county area instead of entering the environment directly through inadequate sanitation facilities or dumping. Pathogens emerge in environments where human excreta enters the environment untreated. Nowadays, pathogens are emerged in Nairobi County where excreta and sewage is directly discharged. Providing sanitation facilities will reduce these pathogens and consequently decrease the amount of diseases (Clasen, 2015). Collecting human excreta results in higher water quality and hygiene (Werner, 2003). Investments in and the maintenance costs of a conventional sewage system are high and therefore it's hard to invest in a conventional sewage system in Nairobi county area. The collection method that the sewchar concept requires, does not need a conventional sewage system and will therefore be less expensive. To achieve better circumstances for future generations it is important that the development of new investments in sustainable sanitation systems does not halt. However, by collecting human excreta instead of direct disposal, the sewchar concept will contribute significantly to sustainable development of Nairobi country as futurity of the people is improved.
The collected human excreta has to be transported from the collection points to the processing plant where sewchar is produced. The only current available option for transportation is with trucks, due to the weight of the collected excreta and the accessibility of the collection points. Even though the use of truck-traffic can theoretically lead to road development, improvement on different social aspects and employment (as will be elaborated in the next sections), the heaviest impact of transport on futurity is air pollution. Air pollution is already a major problem in city areas in Nairobi county, affecting human health and environment (as described in section Biodiversity). Mulaki & Kariuki (2001) found that the total suspended particles (TSP) are above the safety standards of the World Health Organization in the majority of the city areas. In the citycenter and eastern areas the TSP levels are in the highest category stated by the WHO, causing direct health risks. The traffic sector is the largest contributor to the air pollution in Nairobi County (Gatari et al. 2013). The use of trucks for transportation of the human excreta through Nairobi county should be seen in perspective of the total transport system in the area, and the contribution to the total TSP from traffic will probably be negligible. More research is required to
determine the contribution to the TSP and the effects on futurity. Even though the weight of transport on futurity is relatively small, the exhaust gasses for the transportation of the excreta influence the futurity in a negative way.
After transport to the process plant, the excreta will be converted into sewchar. Human excreta is a category of waste that is still waiting for recycling options and sustainable treatment (Fühner et al, 2014). Worldwide, 90% of human excreta waste, is either dumped into the sea or disposed through landfilling in sanitary sites. In less developed countries this percentage is even higher than in the developed world, due to lack of regulations (Werther & Ogada, 1999). With growing populations, especially in third world countries, the total amount of human excreta is only expected to grow
(Danso-Boateng et al., 2015). Using Hydrothermal Carbonisation (HTC), a relatively new pyrolysis conversion technology, can convert relatively wet biomass into biochar or sewchar. The temperatures reached in this process are high enough to kill and remove all pathogens. Besides that, HTC offers the possibility to use generated energy and heat for earlier steps in the process, such as dewatering, decreasing the energy cost for production significantly (Danso-Boateng et al., 2015). Even though the energy balance for the production of biochar through HTC is negative, the effects are not as damaging as current methods of disposal of human excreta in Kenya county, as described earlier in this section. HTC treatment might also affect future generations negatively in the future, but it contributes far more to the futurity than other alternatives used at this moment.
When the sewchar is produced, it can be used as a fertilizer for soil amelioration. Agricultural yields are expected to fall with 50% if agricultural practices are not improved and 12 million hectares of fertile soil is lost every year due to soil erosion. This amount of soil is capable of producing 20 million tons of grain per year (Terrafrica.org, 2014). Lal (2006) states that there is a strong link between quality and agronomic productivity on one hand and and soil organic carbon (SOC) and soil quality on the other. Charred material, such as sewchar, has the potential to increase SOC stocks on long time scales because of the slow degradation of captured carbon (Kimentu et al., 2008). Kimentu et al. (2008) analysed the maize grain yield (tonnes/hectare) on a chronosequence of soils. The study discovered that after a forest was converted to a maize field, maize grain yields dropped exponentially over time and a large part of this exponential drop was explained by the rapid depletion of SOC resulting in desertification and land degradation. Applying SOC sources like charred material to degraded fields proved to increase yields within a couple of years. Charred material has beneficial aspects to improve yields on degraded soils, but the key of its success is sustainable land management. Application of biochar must be supported by local people and knowledge on best-practices must be shared within farmer communities to benefit from the potential of charred material (Gatere et al., 2013).
Overall, the sewchar concept is assumed to have a very positive impact on participation. This is based on the idea that current generations and future generations will benefit from less environmental degradation, higher hygiene and increased soil quality.
Equity
The principle of equity within the used definition of sustainable development focuses on contemporary social justice and equality, but also on geographical equity, which means that localities matter as much as global issues. In this light, the sewchar concept may contribute to equity as it may lead to a reduction of the gap between rich and poor people and inequality in Nairobi County, Kenya, which was the highest in Kenya between 1994 to 2006 (Bigsten et al., 2014). This, because of accessible sanitation, an approachable business model and health equity. In this section, the principle of equity is linked to the four steps of the sewchar concept.
Based on the concept developed by Sanergy, the toilets will be purchased to local people which will result in a beneficial business model. Local residents will become franchise member with Sanergy in Nairobi County. The model can thus be seen as a bottom-up solution to sanitation problems, which contributes to equity through the involvement of different layers of the society. However, this entails a risk as well. Giving power to one company only, increases the risk of, for example, monopolies or exploitation of staff. With the improved local sanitation systems, the amount of pathogens emerging into the environment will decrease. This will result in better health equity, which is defined by Braveman and Gruskin (2003) as “the absence of disparities in health between social groups who have different levels of underlying social advantage/disadvantages - that is, different positions in a social hierarchy”. Montgomery and Elimelech (2007), in addition, state that sanitation and clean water will improve human health and health equity.
Besides health equity and the improvement of economic equality, mobility and employment may increase as well. Since the excreta should be transported after collection, one may assume that there will be road development in Nairobi County to improve the transport possibilities. Also, both transport and road development requires human resources, which may improve employment in the region. However, this entails a risk as well, since it may be executed by big companies, without fairly division of benefits among the residents. In addition, geographical equity is under pressure in Kenya. As demonstrated by Burgess et al. (2013), there is a great ethnic favouritism and segregation in Kenya, resulting from colonial era borders, before the independence of Kenya in 1963. Burgess et al. (2013, p. 4) found: “Across the
1963 to 2011 period, Kenyan districts that share the ethnicity of the president receive twice as much expenditure on roads and have four times the length of paved roads built relative to what would be predicted by their population share.”
The production of sewchar is not possible with ordinary pyrolysis techniques used for dry biomass, due to the moist found in human excreta. For the conversion of wet biomass a relatively new chemical technique has been proposed (Funke & Ziegler, 2010). This technique has not been developed as far as ordinary pyrolysis and initial investments are therefore mostly accessible for the richest layers of the Kenyan society. On the other hand, job positions for different inhabitants are created at the processing plant, but the exact amount of positions created in unknown.
After the production of sewchar, the product is applied on the agricultural areas in Nairobi County. This may lead to improved equity, since the food security will increase due to higher yields and lower prices of agricultural products. In addition, the higher yields will not only improve domestic food availability, but may also result in economic improvements for farmers, since they have more products to sell on (local) markets.
Overall, the sewchar concept offers great chances for the improvement of equity in Nairobi County. However, many possible outcomes are of substantial insecurity and entail many open questions and results. Also, there is quite little know about the national and local priorities in Kenya. Nairobi County contains the capital of Kenya, so it may be expected that this region is socioeconomically prioritized
above more peripheral areas and therefore the sewchar concept is negatively associated with geographical equity. Therefore, the statement that the sewchar concept may contribute to equity is uncertain and entails risks.
Participation
Ideally every inhabitant of Nairobi County should benefit from a new development if this development is ought to be a form of sustainable development. The participation pillar implies that everyone can benefit from a development (open) and that people participating in the development are treated openly and fairly. 60% of Nairobi’s population is living in informal settlements or slums. In such slums income is often generated from diverse sources such as urban farming, waste recycling and garbage collection (Hart, 1973; Thieme, 2013). The sewchar concept might provide job positions for Nairobi’s population.
One option to collect human excreta is via toilet boxes maintained by Nairobi locals as done by the Kenyan company Sanergy. An alternative option would be that toilet systems are provided and maintained by an organization - governmental, non-governmental or private. This research chose to focus on local entrepreneurship because centralized urban planning for sanitation problems have not been successful over the last decades (Chaplin, 2011). Sanitation-entrepreneur projects described in Thieme (2013) showed how local youth in the Nairobi slums were made ‘managers’ of a toilet providing them with a small income and a daily occupation. However, very little is known about the openness of such a business model as in depth information about perceptions of the ‘managers’ was not provided. Therefore very little is known about whether the ‘managers’ considered the model to be fair and open. The fairness and openness of sanitation-entrepreneur projects probably depends on choices such as the amount of toilets, the required investments by the Nairobi locals and whether entrepreneurs earn a fair amount of money.
The transportation phase of the sewchar concept provides working positions for truck drivers and local collectors. This again is highly dependent on choices made by the stakeholders incorporated in the design of the sewchar production chain. First human excreta must be brought to central points along the main roads of Nairobi County because large parts of the Nairobi slums are not accessible by large trucks (Werna, 1998). Available options are to demand that local entrepreneurs organize this step themselves by hiring local people or that the transportation company hires people to transport the excreta from the toilets to the central pick-up points. This choice can’t be made in this report. Therefore a field study should be a part of further research to investigate the willingness of Nairobi people to participate in such a project. The second step of the transportation chain is the transportation of human excreta from central pick up points to a processing plant. The sanergy model assumes that excreta is transported by trucks from the pick-up points to the processing plant. This creates job positions for truck drivers. The degree of participation however, is very dependent on choices made by companies hiring the truck drivers. These companies should pay fair wages. If, for instance, a hiring company would provide a training for truck drivers, the possibility of participating in this step of the production chain would be increased.
A processing plant must be built where the human excreta is converted into sewchar. This offers job positions for Nairobi people which contributes to the participation pillar of sustainable development if these jobs are available for people without very specific education or work experience. On the other hand, investments to be made in a processing plant are high. In order to answer the question of participation, the question must be resolved who will pay for the processing plant. If investments are spread out over a group of stakeholders co-operating in a governance structure the processing plant increases both participation options and equity. If not, a risk would be that a foreign investor or a single investor obtains the ownership of the sewchar production plant. In such a scenario, the openess and fairness of the sewchar production becomes more questionable.
The produced sewchar should be distributed among farmers for further land application. When discussing participation, the question about how easily the sewchar can be accessed by farmers and how sewchar will compete with other fertilizers needs to be asked. Since the 1993 the Government Of Kenya decontrolled fertilizer market prices and cut down on donor imports. Currently, the market for fertilizers is competitive and controlled by 7000-8000 private retailers (Jayne et al., 2003). Sewchar must either compete on a private market or the product must be provided by NGO’s. The question of participation is twofold: farmers should have access to sewchar and on the other hand, sewchar should not compete with the private market for fertilizer.
To evaluate the pillar participation, many questions must be resolved. Therefore the contribution of participation is considered to be uncertain. It should be noticed that many options for participation are available and these options can be included in a business model design. If so, participation levels can be positive.
Biodiversity
The only non-anthropocentric sustainable development principle is biodiversity, which is about ecological well-being and does not take into account the benefits that human can obtain from it. Since its independence in 1963, the Kenyan population has increased extremely: from nearly 9 million inhabitants in 1963 to nearly 45 million in 2014 (The World Bank Group, 2016). This resulted in higher pressure on available land and its resources. Environmental degradation is a problem that arose as a result. Nairobi county contains one of Kenya’s 52 protected areas namely Nairobi National Park. However, it turns out that this area is threatened by different factors, like land use change due to agricultural expansion and pollution from external sources outside the park (Okella & Kiringe, 2004). In this section the results that influence the implementation of the sewchar concept on the ecosystem as a whole will be discussed.
Discharge of excreta reduces water quality and degrades the environment (Rapport, Constanza & McMichael, 1998; Walsh, 2000). Sewage effluents cause an increase of nutrient concentrations in water bodies. A river located in the area of this research is the Athi river. Studies show that the discharge of untreated wastewater from Nairobi in the upper stream of this river affects the biochemistry in the water. It leads to low oxygen levels, high NH4- ammonium - levels and high CH4- methane - saturation levels. The
latter are a proxy of organic waste pollutions and the saturation of it is way higher than the other NH4 saturation levels for other African rivers (Marwick et al., 2014). Oxygen depletion in water bodies may lead to hypoxia, which occurs in waters when oxygen levels deplete to concentrations lower than two milligrams per liter (Conley et al., 2011). Hypoxia has a negative influence on the ecosystem and it changes the biogeochemical cycles of both nitrogen and phosphorous. A significant consequence of the high NH4 levels, which lead to eutrophication in the waterbody, is the formation of hydrogen sulfide which causes damage to the ecosystem (Zillén et al, 2008). The habitat of some species will shift more to the surface waters with higher oxygen levels and therefore the living area of the species will get more narrow. Zones that suffer from hypoxia for a longer period contain no benthic fauna (Diaz & Rosenberg, 2008). This does not only occur in the upper stream of the Athi river, but the effects are also seen more downstream (Marwick et al., 2014). In other words, biodiversity has proven to decline due to discharge of wastewater from the Nairobi county area into the the surface water of the Athi river. The collection of human excreta will decrease the amount of nitrogen concentrations in the waste waters, which may prevent the loss of biodiversity in water bodies around the Nairobi County area. Prevention of biodiversity loss is also contributed by the reduction of heavy metals, pathogens and contaminants in the water bodies that normally enter the environment (Fühner et al., 2014).
Not only water pollution affects the biodiversity around the Nairobi County area, but also the high levels of air pollution (Mulaku & Kariuki, 2001). Industrial activities and vehicles in particular are the main sources of air pollution in this region. The transport that is needed within in the sewchar chain is likely to cause more air pollution. Nitrogen emissions can lead to acidification and eutrophication of water bodies, resulting in higher mortality rates of certain species and eventually loss of biodiversity. Also, terrestrial plant compositions may change due to higher nitrogen levels, which will lead to loss of certain species and higher abundance of others (Erisman et al., 2013). Another negative impact of the transport step in the sewchar concept is potential additional road development around Nairobi. This can lead to habitat fragmentation, road kills and traffic noise that can drive away certain animals (Forman & Alexander, 1998). In short, the transport step of the sewchar concept will negatively affect the biodiversity pillar of sustainable development. However, it needs to be mentioned that the negative impact of air pollution and road development on biodiversity will be just for a negligible part caused by the sewchar concept, and therefore the negative contribution is relatively small.
The reduction of the amount of human excreta entering the environment due to the collection as mentioned before, will reduce water pollution in particular (Fühner et al., 2014). Either way, when human excreta is converted into sewchar trough hydrothermal carbonization, the problems concerning the excreta with pathogens, heavy metals, organic and inorganic contaminants still need to be addressed. HTC removes all pathogens from the excreta, but heavy metals are still incorporated in the solid matter after the dewatering process (Werther & Ogada, 1999). However, sufficient ways to minimize heavy metal concentrations are available, using acidic mediums in which the heavy metals dissolve. During pyrolysis and carbonisation processes emissions of dioxins and furans can occur. They are undesired by-products
pyrolysis and combustion and are highly toxic in minimal concentrations and have destructive effects on animal health, causing a serious threat to biodiversity when released (Werther & Ogada, 1999).
Heavy metals and pathogens will be reduced due to the conversion of human excreta into sewchar. The emissions of dioxins and furans will negatively influence the biodiversity. Undesired by-products do not need to be released and therefore have no positive as negative impact on the biodiversity. However, these results are based on a study that used sewage sludge instead of pure human excreta as the start product of sewchar (Werther & Ogada, 1999).
The last step of the sewchar chain is the application of it to the soil. The effects of biochar on soil biota show an increased diversity in bacterial groups and an expansion of the soil bacteria community in mass (Thies & Rilling, 2007; Atkinson, Fitzgerald & Hipps, 2010). Some of the bacterial groups support metabolic pathways in root systems (Thies & Rilling, 2009). Fungal networks expand further when charred material is added to the soil which is important for the bioavailability of nitrogen and phosphorous (Miller et al., 2002). For invertebrates application of charred material has no profound advantages but some species of earthworms are reported to digest biochar (Topoliantz & Ponge, 2005). Soil biota is fundamental for maintaining ecosystem integrity in arid systems as soil biota contribute to nutrient availability in soils (Whitford, 1996). If agricultural land is abandoned, soil quality is important to determine how rapid natural vegetation will recover from the disturbance caused by agricultural activity. The recovery time for natural natural vegetation takes decades when the soil quality is depleted (Lesschen et al., 2008). Application of sewchar, which is a soil organic carbon, improves the soil quality and on the long-term it could provide the biodiversity in Nairobi (Kimetu et al., 2008).
The effects of the sewchar concept on the biodiversity in Nairobi county area differ among the chain of the sewchar concept. The collection of human excreta will prevent aquatic biodiversity loss by reducing the amount of pollutants in the wastewaters. Terrestrial biodiversity will be improved on the long-term when sewchar is applicated to the soil due to more soil biota and higher soil quality. The effects of transport and the process shows to be negative. However, it is uncertain to what extend these influence the biodiversity due to the lack of research in these fields. The negative impacts are also highly dependent on the scale size of the sewchar concept.
Discussion & Recommendations
In this research report different theories and results have been presented. In this chapter, critics on the research will be demonstrated and a discussion will be set up about the reliability and assumptions on the subject matter.
As briefly noticed in the theoretical framework, criticism on the definition of sustainable development provided by Haughton (1999) has been presented by Jabareen (2008). The greatest point of critique stated by Jabareen (2008) is the lack of an economic view on sustainable development in the acquired definition. Haughton (1999) does not focus on the affordability of sustainable development at all - his definition is one a ideological kind. In addition, the four principles of sustainable development do not entail, for example, integrative management techniques or the global agenda, which are mentioned in other definitions of sustainable development (Jabareen, 2008). In short, the definition provided by Haughton (1999) is not holistic and thus should be applied with a critical stance. Also, this research report only provides results for the first exploratory phase of the possibilities of the sewchar concept, with a more ideological view. Future research should focus on characteristics such as the costs and benefits in more detail.
In this case study the franchize concept of Sanergy is used as an inspiration for the excreta collection. The sanitary units are operated by local entrepreneurs, who pay Sanergy to operate the units. Information is required about the payback-time of this investment and comparison with the costs of a non-commercial approach such as NGO aid-programme or in the form of an integral governmental alternative for sewerage systems, healthcare measures, employment and environmental protection. Non-commercial forms might contribute more to the equity and participation in the region. The same applies for the transportation services responsible for the transport of the excreta from the collection points to the process plant. For the production process possibilities should be explored whether the production of sewchar can be incorporated in current available powerplants or other institutions in the Nairobi region that are able to conduct thermochemical processes, of a new production plant is requisite. For the application chain, insights are needed in the effects of the commercialisation of the sewchar product. Bringing the product to free markets enhances the risk that improvements on equity and biodiversity in the region are diminished, whereas local distribution of the product to farmlands has the opposite effect.
More technological insights are required for the hydrothermal conversion processes of purely collected excreta instead of sewage sludge. Due to a lower water content of excreta compared to sewage sludge one will expect that there is a lower need for energy. This is the case because of the high energy demand for dewatering. Possibilities to reuse waste heat for energy generation or heating purposes should also be taken into account.
During the performed research, the researchers came across some of their own shortcomings. Besides the lack of economic insight, other knowledge was insufficient as well to make this report to its full potential. For example, information about the local socioeconomic circumstances and therefore manners, was not fully potential. Hence, there were made several attempts to get in contact with the
company Sanergy. However, this was unsuccessful. In future research, information obtained from Sanergy about the practical performance of their concept could be a valuable addition to the results.
In addition, as the researchers began with little knowledge on the sewchar concept and area, literature findings were based on certain assumptions and limited. Already in the end phase of the research, a handful of useful articles were found, but could not have been acquired to its fully potential. Therefore, this research functions as a report to clear the way for further research, with bearing the different discoveries and uncertainties in mind.
Conclusions
This report demonstrates an evaluation on the desirability of the implementation of the sewchar concept in Nairobi County, Kenya. To answer the research question - ‘To what extent can the sewchar concept contribute to sustainable development in Nairobi County, Kenya?’ - both the production chain of the sewchar concept and sustainable development were integrated in a model. This was done in order to find common ground within the interdisciplinary research. The report shows evaluations on the four principles of sustainable development (futurity, equity, participation and biodiversity), linked to the four steps of the sewchar concept (collection, transport, process and application).
As shown in the different sections and figure 4, the results were quite divergent. Overall, one may conclude that the sewchar concept can contribute to sustainable development. Mostly the pillars futurity and biodiversity, since it reduces pathogens emerging into the environment, improves soil and water quality, human health, and has beneficial effects on future generations through, for example, land degradation. The results of these two principles are the most certain as well. As shown in the results and discussion section, most uncertainties and potential disadvantages of the concept lie in the principles of equity and participation, because the different potential business models influence the outcomes substantially and the geographical equity in Kenya is under debate. The principle participation is qualified as uncertain, because the effect of an implementation of the sewchar concept on open and fair participation of Nairobi’s inhabitants is too uncertain or unknown.
Based on this research, with an ideological stance acquired through Haughton’s definition of sustainable development (1999), one may conclude that there is potential for the sewchar concept. However, future research on possible business models and cost-benefits analyses and small-scale, local first initiatives must demonstrate the socioeconomic functioning and acceptance of the concept.
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