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Phytofuel; a multi-problem solution
for Tanzania
An assessment on the possible application of
phytoremediation and biofuels
Isabel Bos 10000740
Fleur van Crimpen 10345442 Mabel Gray 10437681 Hidde Nab 1041167
Supervisor: Dr. Maartje Hamers University of Amsterdam Interdisciplinary Project, 2015 Image: Wikimedia.commons (edited)
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Acknowledgements
We would like to express our gratitude towards;
Maartje Hamers, for her supervision during the production of the report and her guidance in the interdisciplinary process
Kenneth Rijsdijk, for his expertise and constructive feedback Coyan Tromp, for her seminars on interdisciplinary research Leo Hoitinga, for his supervision and advice concerning the soil analysis
3 Contents Acknowledgements ... 1 Abstract ... 4 1 Introduction ... 4 2 Problems ... 5
2.1 Current energy usage ... 6
2.2 Food security ... 6
2.3 Profitability ... 7
2.4 Contaminated soil ... 7
2.5 Multiple problem solution ... 9
3 Methods ... 10 4 Results ... 11 4.1. Location ... 11 4.2 Soil analysis ... 11 4.3. Multi-problem solution ... 12 4.3.1. Applicability of phytoremediation ... 12 4.3.2. Physiology of phytoremediation ... 12
4.3.3. Proposed method of approach ... 13
4.3.4. Applicability of phytofuel ... 14
4.4 SWOT analyses ... 15
4.4.1. Broad SWOT analysis for the production of biofuels ... 16
4.4.2. Conclusion of SWOT analysis for the production of biofuels ... 17
4.4.3. SWOT analysis for the production of bioethanol from corn in Tanzania ... 18
4.4.4. Conclusion of SWOT ... 19 5 Discussion ... 20 6 Conclusion ... 21 References ... 22 Appendix 1 ... 26 Lab report ... 26
Heavy metal analysis ... 26
Organic compounds analysis ... 27
Appendix 2 ... 27
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Abstract
Africa is confronted with several problems that come forth from overpopulation; lack of fossil fuels, food scarcity and pollution. Due to a rising population, the demand for fossil fuels will increase with its detrimental effect on climate change. This might reduce crop yield and thereby reduce food security. Pollution of soils causes diseases in populations. Actions should be taken to mitigate these issues but the profitability of these actions is a problem on its own. With this study it is attempted to come up with an interdisciplinary “multiple problem solution” by the usage of phytoremediation. The possibility to use the biomass from phytoremediation for the production of biofuels is explored. This is done by performing soil analysis for cadmium content in samples taken from the target region, Mto wa Mbu in Tanzania. Additionally, a literary study is performed to assess the applicability of the multiple problem solving approach. Finally, several SWOT analyses give insight in the strengths, weaknesses, opportunities and threats that go hand in hand with this approach. It is found that there are several options for the production of energy from the contaminated biomass that is gained from phytoremediation. However, more research is needed to stimulate and perfect the whole method.
1 Introduction
Nowadays, there are several global problems. This can mainly be attributed to the fact that the human population has doubled since 1960 and still rises exponentially (Gillard, 2002). This phenomenon is for a significant part due to the industrial revolution, which provided some communities with modern conveniences. Products are abundantly available and cost less compared to the prices before the industrial revolution. This makes it easy to dispose and repurchase (Cooper, 2005). Unfortunately, this luxurious way of living and higher standards of life has negative results in several ways. More industrial waste has resulted in health issues due to improper disposal of toxic chemical compounds (Polgreen & Simsons, 2009). Thereby, modern society requires large amounts of energy, which is mostly depending on fossil fuel availability. Fossil fuels are still the number one energy source (Shafiee & Topal, 2009). But due to the fact fossil fuels are finite and starting to deplete, a transition from the current fossil fuel trend to a more sustainable energy source is necessary. Not only a source that is preferred to be infinite, but also results in less greenhouse gas emission. Namely, because of the rise in population and industrial activity the concentration of greenhouse gasses in the atmosphere increases, resulting in a rise in temperature worldwide (IPCC, 2014; Abrahamson, 1989).
The problems mentioned are based on environmental, health and energy issues. Scientists, among others, are trying to find solutions, which cost scarce time, money and energy. But, what if there are solutions created that can solve several problems at a time? It might be necessary to develop multi-problem solutions to make progressive changes. This report examines a multi-multi-problem solution and whether it is viable to implement it in reality.
This report describes the use of phytoremediation, extraction of heavy metals from the soil by plants, and how these plants subsequently can be used as biofuel. This would result in less
environmental, health and energy issues due to the decontamination of soils and cleaner energy usage. This multi-problem solution will from now on be referred to as the phytofuel solution. Phytofuel
5 meaning the biofuel produced out of plants used for phytoremediation. The question that this report will try to answer is:
“To what extent can the phytofuel solution serve as a viable multi-problem solution to the
environmental, health and energy issues in the Mto wa Mbu region, Tanzania?”
To answer this question, an interdisciplinary approach is necessary. This is because a multi-problem solution exists of several aspects that need to be examined from different perspectives to find common ground. It is hoped to find the solution to the several problems by finding in what manner the aspects are linked to each other and for common ground. The solution of the different problems forms the interdisciplinary factor of this research. The disciplines that are addressed are earth sciences, ecology and business studies. To bring this project to a success, these disciplines will all contribute to the search for common ground between the aspects food security, current energy usage, contaminated soils and profitability.
First, this report will describe the problems hoping to be solved by the phytofuel solution, namely the environmental, health and energy issues. Secondly, the report will describe the target location and the soil analysis that is done with soil from the Mto wa Mbu region. Then, the different parts of which the solution consists will be described, namely phytoremediation and biofuel production. Last, strengths, weaknesses, opportunities and threats analyses (SWOT) are made for the production of biofuels and the production of bioethanol in Tanzania. This is done to determine whether the solution is viable and can function as a multi-problem solution.
2 Problems
As stated in the introduction, there are several worldwide problems that are challenging humanity. This report focuses on some environmental, health and energy issues.
Four key aspects are posed: food security, current energy usage, contaminated soils and profitability. These aspects play an important role in the phytofuel solution. Those are factors that can hopefully be optimized when the solution is implemented. As shown in Figure 1, these four aspects are connected to each other, which is a must when working with multi-problem solutions. It means that they have common ground where a solution can be found. If the common ground is determined and there are possibilities to
6 transform that into a solution, there is a high chance that all aspects are affected (in a positive way). Next, the aspects will be discussed briefly.
Also, by defining the theories that are part of these aspects, a theoretical framework can be constructed. The theories will be discussed briefly as well for each aspect.
2.1 Current energy usage
Energy production has to rise if the requirements of a growing world population and a higher quality of life are to be met. A significant part of the energy used worldwide is coming from fossil fuel production, which is an exhaustible energy source and has negative effects on the environment (Shafiee & Topal, 2009). It is expected that the oil demand will increase from 85 million barrels in 2008 to 105 million barrels by 2030 (Habib-Mintz, 2010), which will contribute to the enhanced greenhouse effect. The fourth assessment report of the IPCC stated a rise of average global temperature between 2.0-2.4 Celsius by 2015 (Habib-Mintz, 2010). Due to climate change, harvests can fail and food sufficiency will decrease when no steps are taken towards a future which offers higher food security (IPCC, 2014). Here, global warming is a theory and an important factor for this study. It is a crucial motive for wanting to develop a solution that can tackle several problems, both direct and indirect contributing to the enhanced greenhouse effect. But by wanting to influence several problems, this study will only briefly focus on solving this particular problem.
It is therefore important to induce a shift to a more sustainable source of energy. A suggested method to produce sustainable energy is phyto-energy (i.e. energy harvested from plants). One form of phyto-energy is biofuel. There are two types of biofuel, the first-generation and the second-generation. The first generation biofuel is derived from plant matter and residues such as agricultural crops,
municipal wastes, and agricultural and forestry by-products, according to Habib-Mintz (2010). First-generation biofuel is mostly known as biodiesel and bioethanol (Peters, 2008) which are based on oil crops such as rapeseed, sunflower or soy. Bioethanol can be made out of crops such as sugar cane, wheat or corn (Peters, 2008). Normally, only a part of the feedstock crop is used for production of biofuel. This is in contrast with the second-generation biofuels. In this generation biofuels, all the biomass is used to produce liquid and so takes advantage of the whole crop according to Peters (2008).
Fossil fuel production and mining are polluters of scarce agricultural land and can affect the food security of countries where the pollution takes place, which is the case in Tanzania. However,
implementing phytofuel as an alternative has its own downsides. That is where food security comes in.
2.2 Food security
According to the USAID (1992) food security is when ‘all people at all times have both physical and
economic access to sufficient food to meet their dietary needs for a productive and healthy life’
(FAO, 2006, p.2).
Due to rising fossil fuel prices more and more developing countries, including Tanzania are examining possibilities to substitute fossil fuels in the transport sector with locally produced biofuels (Peters, 2008). Developing countries created a market opportunity to utilize their comparative
7 of land are planned to be used to produce these crops which can lead to land-use conflicts according to Peters et al. (2008). Because biofuel is produced from (edible) crops, another conflict arises, known as the food versus fuel problem (HLPE, 2013). Here, the question is whether agricultural land should be used to produce biofuel or food, since there is not enough suitable land to produce both. This study does not includes the willingness of the local population toward biofuel production on agricultural ground, but it is important when doing a location analysis when the project is implemented. For now, this report tries to find a solution to bypass the food versus fuel problem when producing biofuels.
2.3 Profitability
Even though the acres of contaminated land are still increasing worldwide, governments are not willing to spend money for cleaning the soil (Peters et al., 2008). There are several ways to remove the heavy metals from the soil, but most methods are quite time consuming and not very lucrative, such as chemical addition, in-situ or ex-situ cleaning or soil removal. Due to the fact that cleaning the soil is an expensive and long process, an approach which cleans the soil but will be profitable needs to be created. This so governments are willing to cooperate and invest time in a project like this. Yet, profitability does not only mean profit in money, it translates to the benefits for the community and environment as well. If the benefits are high, there will be more incentive for governments and international bodies to implement such a project.
A multi-problem solution can lead to higher time efficiency, since several problems are tackled at once. If a cheaper and more sustainable way of energy production can be found, this can bring profit to the country where it is implemented. In business, it is common to evaluate a business venture with the help of a SWOT analysis. The SWOT analysis is a theory that is used as a strategic planning tool (Kotler & Keller, 2012). This theory is used as the theoretical framework for the business perspective of this research. The SWOT theory suits this particular project because it can assess the potential benefits and give leverage to the public bodies in charge. The other disciplines involved in this research focus on the technological aspects. The results of the technological research is implemented in a SWOT analysis and thus creates an integrated evaluation.
2.4 Contaminated soil
The discipline of ecology contributed to the theoretical framework by reasoning from the theory of “ecosystem well-being”. Our quality of life is directly influenced by the well-being of the ecosystems humans live in (WHO, 2005). The ecosystems provide humanity with ecosystem-services such as food, water and shelter. From the discipline of ecology, the well-being of both humans and their ecosystems was added to the theoretical framework.
One of the current issues that mainly developing countries are facing is the pollution of heavy metals. However, even though heavy metal pollution has decreased in most developed countries, it is still an ongoing issue worldwide (Järup, 2003; Chen et al., 2005; Cheng, 2003). Multiple studies have been performed in China to assess the potential threat of heavy metals to human health. Cheng (2003) found that China’s industry is one of the main sources of heavy metal contamination, spreading heavy metal particles through the air and into soil and water. This leads to heavy metals entering the food
8 chain, harming both humans and animals (Cheng, 2003; Järup, 2003; Li, Poon & Liu, 2001; Chen et al., 2005).
As mentioned above, a lot of research is focusing on heavy metal pollution in developed countries that are already investing in scaling down the amount heavy metals in the biosphere.
However, less research is conducted in developing countries where levels of heavy metal contamination are still rising (Järup, 2003); (Nriagu, 1992). Nriagu, in as early as 1992, mentioned the oncoming threat of heavy metal pollution in Africa. In this study, it was estimated that between 15 and 30% of infants in densely populated areas were already suffering from lead poisoning. This shows the importance of tackling potential threats that heavy metals are posing to human and environmental wellbeing.
One of the most concerning heavy metals is cadmium (Cd+) (Järup, 2003). According to the
Agency for Toxic Substances and Disease Registry (ATSDR) (2008), cadmium is insoluble in water, except for some cadmium salts. Neither does it burn, except for its powdered form of which combustion will lead to the release of toxic fumes (ATSDR, 2008). Cadmium mostly originates from the mining of zinc and is used in batteries, plating, plastics and fertilizers (ATSDR, 2008). The most expressed source of cadmium pollution is therefore waste from both industries and households and mining sites (ATSDR, 2008; Willburn, 2007). However, other sources of cadmium have been speculated to contribute to the accumulation of cadmium in organisms. Still, cadmium is one of the rarer in nature amongst the heavy metals of concern (Wedepohl, 1995; Sigel & Sigel, 2013). The most stressing characteristic of cadmium, however, is its ability to accumulate in ecosystems (Muchuweti et al., 2006). It easily enters the soil and thereby crops, vegetation and dusts (ATSDR, 2008). Muchiweti et al. (2006) have shown that illegally grown crops in Zimbabwe contain large amounts of cadmium; as high as 18 times the amount permitted by EU standards. As mentioned earlier, this poses major threats to human wellbeing, especially in developing countries, which introduces the topic of human health.
Cadmium can enter the human body both by respiration and ingestion, where respiration is the most efficient route of uptake (Sigil & Sigil, 2013). The main source of cadmium varies between airborne cadmium and ingestion through contaminated foods (Sigil & Sigil, 2013; Flick, Kraybill, & Dlmitroff, 1971). Once stored in body tissue, cadmium has a half-life time of 10 to 30 years. Cadmium has been associated with several forms of cancer, amongst which lung cancer (Nawrot et al., 2006; Sigil & Sigil, 2013). Additionally, it is strongly mentioned by Sigil & Sigil (2013) that cadmium causes renal diseases (i.e. diseases of the kidney) such as nephritis, nephrosis and others. Hellström et al. (2001) found that low exposure to cadmium already leads to an increased risk of contracting end-stage renal disease (ESRD). Cadmium is also associated with arterial diseases. Navas-Acien et al. (2004) have shown that cadmium significantly correlates with Peripheral Arterial Disease (PAD). This study, shockingly, had no individual in their research population with a cadmium blood value above 5µg per litre, the Occupational Safety and Health Administration’s permitted amount. Furthermore, Sigil & Sigil (2013) suggest that the occurrence of PAD is caused by cadmium induced atherosclerosis which can cause arterial hypertension (i.e. elevated blood pressure) and fatal vascular diseases that follow from hypertension such as strokes, cardiac arrests and heart failures. Schroeder (1965) supports this claim by showing a significant
correlation between hypertension and renal cadmium.
Furthermore, cadmium exposure can lead to osteoporosis and osteomalacia and thereby result in fractures (Åkesson et al., 2014; Sigil & Sigil, 2013). These diseases lead to an additional disease which Nordberg, Fowler and Nordberg (2014) described as “the most severe form of chronic Cd poisoning” (pg.
9 692); Itai-Itai disease. This disease roughly translate to English from Japanese as “it hurts-it hurts
disease”. Weakening of the body and fractures resulting from osteoporosis and osteomalacia result in intense pains in the affected individual, hence the name (Nordberg, Fowler & Nordberg, 2014).. Other symptoms of cadmium poisoning have been speculated, such as anaemia, nerve and/or brain damage but the correlation has not yet been proven due to possible co-founding factors.
2.5 Multiple problem solution
Taking into the account the above mentioned information in the theoretical framework, a new approach is suggested in order to solve the ongoing problems in a cheap and environmentally sound way. The approach, or multi-problem solution, that is analysed in this report is the phytofuel solution. It is proposed to use phytoremediation on a polluted soil in order to remove the chemical pollutants (i.e. cadmium) of interest. Phytoremediation could be used to remove heavy metals from Tanzanian soils, resulting in a better ecosystem and human well-being. Additionally, corn or soy is a fast growing plant and is relatively cheap compared to more resistant plants such as willows. But, when plants
are used for phytoremediation one ends up with a high amount of contaminated biomass (Ghosh & Singh, 2003). This means a lot of useless biomass is produced, which will eventually rot and release the cadmium back into the same or another ecosystem. One of the ways to safely clean this biomass is the concept of phyto-mining (Ghosh & Singh, 2003). Heavy metals can be extracted from the contaminated plants and could then be safely stored or recycled for better use. However, it has not been found to be cost effective to extract metals from plants and this method is therefore not widely used. Therefore, another option should be considered, the above mentioned phytofuels. The contaminated biomass could potentially be used for phytofuel production.
The production of biofuel is often limited due to the lack of land and/or resources. Due to the fact that the contaminated biomass from phytoremediation originates from soils that were not suitable for crop production due to heavy metal pollution, the debate of food versus fuel is taken into account and partly solved. Additionally, phytoremediation will clean the target soil in the long term and render it available for future agriculture.
What was needed was something that would restore ecosystems and somehow render the least amount of losses possible or rather; a profitability. The problems of pollution and shortages were combined and it was then attempted to find one overshadowing solution. This way it would be able to clean ecosystems and in the meantime render economical gains by reducing shortages and fossil fuel dependence. It was found that we could achieve this by using phytoremediation and biofuels. Figure 2
10 shows the possibilities for further integration and where insights should be combined. In this chapter it is aimed to assess the possibility to apply the above mentioned method to our target location; Tanzania.
3 Methods
Primarily to starting the research, several steps have been undertaken to ensure a fully interdisciplinary approach. These steps included several seminars in order to overcome gaps between the disciplines of the authors (i.e. earth sciences, business sciences and ecology). This was achieved by using mind-maps, visualisations (Figure 2) and data management tables in order to build bridges and find common ground between the different disciplines. The result of this preparative work is the report in its entirety. Then, the method of this research was determined.
Firstly, a target region Mto wa Mbu in Tanzania will be selected and then analysed for soil heavy metal and organic content. Additionally, a literature research has been undertaken to determine general information about this region and to assess the possible application of phytoremediation in this region.
Once this region has been selected, two biological replicates will be taken, each at a different location. These samples will be approximately 500 g allowing two technical replicates during their analysis. The heavy metal and organic matter content will be measured at the University of Amsterdam, at the FNWI faculty, by using an ICP mass spectroscopy analyser. A more detailed description of the lab report can be found in appendix 1. The purpose of a soil analysis is to emphasize the importance of a target location study, since the right conditions have to be met to be able to implement the phytofuel solution to a certain area. By analysing the contaminants and nutrients in the soil, it can be determined whether crops can be grown here and subsequently used for phytofuel production.
Next, it was studied whether phytofuel production from the resulting biomass is a profitable option for Tanzania. Furthermore, it is studied what the possibilities are to safely remove cadmium from these phytofuels in order to avoid re-entry in the ecosystem.
Finally, several SWOT-analyses are conducted in order to create an overview of the several Strengths, Weaknesses, Opportunities and Threats the above mentioned approach poses. This is in order to evaluate the approach and influence of the phytoremediation and to point out where further research needs to be done.
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4 Results
4.1. Location
It was decided to use an African region as focus for this report. Heavy metal pollution of water, sediments and soil is very common is Africa. Lake
Victoria in Tanzania is one of these sites which is polluted due to domestic waste and industrial activity (Yabe et al., 2010). Small scale gold mining contributed to this problem due to the fact that mercury (Hg) was used around the lake and contamination (mg/kg) of lead (Pb) (54.6 ± 11.1), cadmium (Cd) (7.0 ± 2.1) and Hg (2.8 ± 0.8) can be found at the Tanzanian coast. Water is contaminated with Pb (1.4 mg/L), Cd (0.02 mg/L) and nickel (Ni) (0.13 mg/L) (Yabe et al., 2010).
This report focuses on the Tanzanian region, Mto wa Mbu (Figure 3). Here, the main source of contamination is the use of fertilizers that contain cadmium, since the target location is an area used for agricultural activity. Harvested crops and products are known to be contaminated with heavy metals, due to the fertilization of the soil (Semu & Singh, 1995). The
crops take up part of the cadmium, intoxicating people that digest the crop. The increasing exposure to cadmium can lead to several health issues amongst the local population (Polgreen & Simons, 2009). This exposure can be indirect through the use of contaminated irrigation water for
crops.
4.2 Soil analysis
The samples were taken in a field and near a riverbed (Figure 4). The soils were analysed for heavy metals and organic matter. It is found that the field soil has an organic content of 6.9% and the riverbed soil has an organic content of 5.2%. This corresponds to the soil organic matter topsoils generally contain, ranging within
approximately 1% to 6% (Troeh & Thompson 2005). The results from the heavy metal analysis can be found in Table 3 and Table 4 in appendix 1. The results are presented in mg/kg and mg/L for comparison with the literature results in Yabe et
al. (2010) as shown in Table 1.
Figure 3: Location of Mto wa Mbu region (image source: Google earth, retrieved 2015)
12 Table 1: recommended maximum amounts of heavy metal soil content (Yabe et al., 2010) and found values for heavy metals of interest (in milligram per kilogram soil)
Heavy metal Recommended soil content Field soil content Riverbed soil content
Pb (mg/kg) 150 <12 <11,5
Cd (mg/kg) 5 <1,0 <0,95
Ni (mg/kg) 100 <102,3 <84,3
4.3. Multi-problem solution
4.3.1. Applicability of phytoremediation
The soil contamination problem can be solved with the environmentally friendly method of soil
sanitation, namely phytoremediation. Salt et al. (1998) wrote, with the use of Cunningham et al. (1995), that the definition of phytoremediation is “the use of green plants to remove pollutants from the
environment or to render them harmless” (p. 2). Here, pollutants can be both organic and inorganic and
can be extracted when solid, liquid or gaseous. Therefore, different phytoremediation techniques (phytodegradation, -stabilization, -volatilization, -extraction and enhanced rhizosphere biodegradation) are applicable for different contamination circumstances (Singh & Ward, 2004). The above-mentioned green plants can vary from trees to grasses, but some are for example more resistant against pollutants and others have higher extraction rates (Pivetz, 2001). Phytoremediation is applicable to different situations, such as ground water, where phytodegradation and –volatilization can be applied. It may be the case that alternations have to be made when the water is too deep for the roots to reach. In some cases, the groundwater is pumped to the surface where the plants can clean the soil before it leaches back into the aquifer. Surface water and wastewater can be sanitised with aquatic plants using phytodegradation or enhanced rhizosphere biodegradation. And soils, sediments and sludge can be sanitised with all remediation techniques (Pivetz, 2001).
4.3.2. Physiology of phytoremediation
The word phytoremediation finds its origin in the Greek word for plant (phutón) and the Latin word for cure (remedium) and technically, that is exactly what is going on. As mentioned above,
phytoremediation refers to the usage of plants to potentially “cure” a polluted area. They do so by several mechanism, that too, were mentioned earlier. In this study the focus lies on the process of
13 phytoextraction. This is mainly due to the fact that the
target of this research is to clean soil in such a way that cadmium cannot re-enter the ecosystem and can safely and efficiently be removed.
Phytoextraction offers the means to do so, since heavy metals are taken up in the plant’s biomass and can thereby be removed by harvesting the plant (Figure 5).The effectiveness of phytoextraction by a plant depends on the bioavailability of the target pollutant in the soil (Jabeen, Ahmad & Iqbal, 2009). If the concentration of the pollutant is higher, the possibility for the plant to take up the
pollutant becomes greater. However, plants can only survive specific concentrations of pollutants. Additionally, growth is probably stunted even at lower concentrations. This, however, is not always the case. Padmavathiamma and Li (2007) suggest that Thlaspi caerulescens or Alpine
Pennygrass grows bigger leaves, fruits, seeds and stems
when it originates from a population growing on soils with relatively high cadmium concentrations. Plants tend to take
up heavy metals through mass flow, diffusion and root interception (Jabeen, Ahmad & Iqbal, 2009). Mass flow resembles the pollutants that enter the roots through water uptake, diffusion means the movement of chemicals from a high concentration to a low concentration and root interception defines the event when roots take up chemicals they meet during growth. Either metal-chelating substances need to be added to the soil to make heavy metals available for uptake, or the plant needs to release acids into the rhizosphere to dissolve heavy metals (Jabeen, Ahmad & Iqbal, 2009; Padmavathiamma & Li, 2007). Once the heavy metals become available to the plant, their entry in the cell depends on plant species and type of heavy metal (Jabeen, Ahmad & Iqbal, 2009). Cadmium can enter a cell through a cell membrane without a metabolic process; it can pass through the membrane by a combination of
diffusion and sequestration (Jabeen, Ahmad & Iqbal, 2009). Then, the heavy metals can be transported throughout the plant by xylem (Padmavathiamma & Li, 2007).
4.3.3. Proposed method of approach
It was found that the soil in the Mto wa Mbu region contained values of cadmium soil content below 1,0 mg/kg soil in the field samples and below 0.95 in the riverbed samples. Research has shown that
Brassica napus (rapeseed) was able to tolerate cadmium values up to 40 mg/kg, proving this species to
be a viable option for the area (Van Ginneken et al., 2005). However, the plants were significantly stunted in growth and biomass production. On the other hand, B. napus had the advantage of being mildly-tolerant to soils containing multiple heavy metals as long as the heavy metal contamination is limited to non-extreme conditions (Table 2) (Marchiol et al., 2004). However, B. napus was not as effective as Raphanus sativus (radish) but B. napus is a commonly used crop for oils (Marchiol et al., 2004). It is therefore expected that the threshold to apply B. napus is lower than that of radish.
Figure 5: Simplified graphical representation of heavy metal transport in and around a plant (Padmavathiamma & Li, 2007)
14 Table 2: Treatment for Brassica napus and Raphanus sativus. Both were stunted in growth and biomass production but were still viable for these values
Heavy metal Control soil (mg/kg) Contaminated soil (mg/kg)
Cd 0.90 38.6 Cr 18.2 165 Cu 37.9 286 Ni 19.6 46.9 Pb 37.9 884 Zn 66.1 6685
Another option could be a species from the same genus, B. juncea (Indian mustard). B. juncea was found to be a better accumulator of heavy metals than B. napus and remained viable on a soil containing multiple heavy metals (Van Ginneken et al. 2005). Moreover, B. juncea was able to accumulate multiple kinds of heavy metals. However, it required heavy metal-chelating substances such as synthetic
chelating agents or degradable organic acids (Van Ginneken et al., 2005). This means that B. juncea has more potential than B. napus but requires more intense management. Both B. napus and B. juncea are viable sources of biomass for the production of phytofuel (Van Ginneken et al., 2005).
4.3.4. Applicability of phytofuel
The obtained biomass by phytoremediation is contaminated with cadmium, the most volatile of the heavy metals. One of the more obvious ways to process cadmium turned out to be thermal processing, such as combustion or gasification (Nzihou & Stanmore, 2013). However, when cadmium containing biomass is ignited, cadmium will volatize and might become fine particles in the air (Nzihou & Stanmore, 2013), capable of traveling long distances and entering ecosystem and the human body through
respiration (see “contaminated soil”, chapter 2.4). It is therefore important to take this into account
when looking into possible ways of harvesting energy from the biomass.
Nzihou and Stanmore (2013) recommend the low temperature pyrolysis method for combustion of biomass attained by phytoremediation. Pyrolysis is the thermal decomposition of materials in anoxic circumstances (Mohan, Pittman & Steele, 2005). This will result in the production of so called bio-oil or pyrolysis oil (Mohan, Pittman & Steele, 2005; Nzihou & Stanmore, 2013; Van Ginneken et al. 2007). This method is composed from two previous researches by Stals et al. (2010) and Keller et al. (2010). Stals et
al. (2010) suggest flash pyrolysis (i.e. quickly exposing material to 350 till 450 °C) and Keller et al.
recommend performing the flash pyrolysis in reducing conditions in order to increase the volatilisation of cadmium. It was found that performing flash pyrolysis at 350 till 450 °C resulted in a 4% retention rate of heavy metals in the bio-oil. Additionally, using the recommended reducing conditions, this rate should decrease. This would, however, result in more cadmium in the flyash (airborne ash). According to Nzihou and Stanmore (2013) this will pose no threat because most systems are provided with an ash cleaning system, only releasing insignificant amounts of cadmium into the biosphere. According to
15 Mahon, Pittman and Steele (2005), bio-oil is to become a viable economical option due to climate change and it could therefore potentially contribute to Tanzania’s well-fare in the long term. However, standardizing the quality and characteristics of the bio-oil is not possible yet. According to Van Ginneken
et al. (2005) its viscosity, acid composition, free fatty acid content and gum formation make it currently
impossible to guarantee a proper quality for using the oil in engines. Moreover, bio-oil might contain too much ash and carbon residues to be used in combustion engines (Van Ginneken et al. 2005).
Another option for gaining energy from biomass is therefore explored; producing biodiesel through
transesterification (Van Ginneken et al. 2005). Transesterification is the reaction where the organic groups of an alcohol and an ester are switched (Van Ginneken et al., 2005). A triglyceride reacts with an alcohol, such as methanol or ethanol to form diglyceride (Van Ginneken et al., 2005).
Then the diglyceride forms a monoglyceride
and the monoglyceride in its turn becomes glycerol (Figure 6) (Van Ginneken et al., 2005). The resulting methyl esters can be used as biodiesels (Van Ginneken et al., 2005). This method could significantly and relatively cheaply contribute to the production of biofuels and would therefore be a viable option for Tanzania’s economy in the long run. However, governments are not undertaking enough measures to stimulate the popularity of this way of producing biofuel and it is therefore “stunted” in its growth. However, Lammers et al. (2008) suggest that biodiesel will grow in the internal market, while bioethanol production is facing oppositions from the major producers in the short and medium terms. Thereby, biodiesel is gaining attention for its lower emissions which may play a role in climate change mitigation (Habib-Mintz, 2010).
The production costs of biofuels are significantly higher compared to the costs of fossil fuels (Peters, 2008), even now the fossil fuels are known to be finite and the interest for biofuel rises. Nevertheless, fossil fuel demand is still increasing. It is expected that the oil demand will increase from 85 million barrels in 2008 to 105 million barrels by 2030 (Habib-Mintz, 2010). This might induce a shift to the production of bio-oil and biodiesel.
However, how much cadmium from the biomass resides in the biodiesel or where else it is transported to is unknown.
4.4 SWOT analyses
The main focus of this rapport is on the possibility of using plants that have been used for phytoextraction, as a source for the production of biofuel. To examine the phytofuel solution as thorough as possible, several SWOT-analyses were conducted which will be discussed in this section. SWOT-analysis are made for the production of biofuels and the production of bioethanol in Tanzania.
Originally a SWOT analysis is a tool used to assess the positive and negative forces involved in a business venture (Kotler & Armstrong, 2012). The positive and negative forces are divided into internal
Figure 6: Summarized transesterification reaction, a triglyceride reacts with methanol to form glycerol and Methyl Esters (source: wikimedia.commons, taken 2015)
16 and external factors. The internal factors are those that are classifies as the strengths (S) or the
weaknesses (W). The external factors are those that are classified as the opportunities (O) or the threats (T). Below, the matrix of the SWOT is shown (Figure 7).
Firstly, a broad SWOT analysis was assessed for biofuels in general. Second, a SWOT analysis was assessed for the production of biofuel from corn in Tanzania in specific. Third, a SWOT analysis was conducted by generally comparing cleaning the soil with phytoremediation with not cleaning the soil.
Regarding the results, the number of positive and negative aspects does not determine the overall evaluation, as all aspects and arguments are not quantitative but qualitative.
4.4.1. Broad SWOT analysis for the production of biofuels
For the first SWOT analysis, the focal point was the production of biofuels in general. Yet, it was
kept in mind that the focus area of this research is Tanzania which is a developing country.
Therefore, all arguments and aspects as listed below are applied to developing countries. Not
every aspect and argument was listed, it was chosen to only list those of large impact.
Strengths
● Producing feedstock for energy purposes can create rural employment and thus benefit the development in rural areas (Greiler, 2007).
● The introduction of a biofuel industry can increase the income of farmers because of the potential sales of co-products.
● The introduction of a biofuel industry can make the energy supply more secure
● Producing feedstock for energy purposes can be a profitable way of using land that is otherwise without purpose.
● Producing feedstock is a way to green wastelands and avert land degradation. Figure 7: SWOT-matrix
17 ● Biofuels have a relatively short supply chain, it can be produced and used locally (Rutz &
Janssen, 2007)
Weaknesses
● The price of biofuels is dependent on the sale of its by-products.
● In comparison to fossil fuels, biofuels have lower energy contents per volume.
● The production of feedstock for energy purposes consumes land that could otherwise be used for the production of food (Rutz & Janssen, 2007).
● The costs of the production of biofuel often are much higher than the production costs of fossil fuels (Peters & Thielmann, 2008).
● The introduction of biofuels calls for an introduction of technologies that can support this type of energy supply (e.g. engines) (Rutz & Janssen, 2007).
Opportunities
● With the introduction of a biofuel industry greenhouse gas emissions could be reduced (Greiler, 2007; Peters & Thielmann, 2008).
● The production of biofuels on a large scale could be a way for developing countries to decrease their dependency on crude oil and fossil fuels (Greiler, 2007).
● Numerous initiatives of research are developed because the biofuel industry is getting more interesting due to rising crude oil prices (Peters & Thielmann, 2008).
● Due to economies of scale, biofuels have decreasing or constant prices (Rutz & Janssen, 2007).
Threats
● A competition could form between the production of biofuel and the production of food because of their use of land.
● The biofuel industry alongside the growing demand for food could lead to further increasing food prices (Greiler, 2007).
● The environmental benefits and costs of biofuels are not estimated on the market, thus making it challenging for governments to create systems that embody these benefits and costs (Greiler, 2007).
● Monocropping and the expansion of agriculture is economically interesting but at the same time can cause for the loss of biodiversity (Greiler, 2007).
● With no continuous management of surface water and land, increasing irrigated land will cause for water scarcity to emerge (Greiler, 2007).
● For the production of feedstock for energy purposes, intensive use of fertilizers is required. This harms the local environment by acidifying and eutrophying the surface water (Peters &
Thielmann, 2008).
4.4.2. Conclusion of SWOT analysis for the production of biofuels
Biofuels could have significant benefits for developing countries with climates and land that is suitable for the production of feedstock for energy purposes. In the rural areas, employment can be created. According to Peters and Thielmann (2008), it is crucial for farmers to have access to a market. The absence of access to markets is often mentioned as the most important impediment for economic
18 activity in rural areas. With the introduction of a biofuel industry, the dependence on fossil fuels could be decreased and the access to energy could be increased (Greiler, 2007).
In the more developed, industrialized countries the production of biofuel from crops is increasing (Greiler, 2007). This increase in production results in a decreasing amount of crops that are available for export, which causes food prices to rise which is also associated with the increasing food demand and animal feed because of the vast population growth (Greiler, 2007). While rural areas might find these developments beneficial, the urban poor could see them as a threat (Peters & Thielmann, 2008). In the meantime it creates better chances for farmers in less developed countries to develop their own market because of a decrease in competition with cheap surpluses (Peters & Thielmann, 2008).
Also, biofuels are adding more focus on the requirements for progress in both rural and agricultural development. To lessen the reliance on the import of fuel and food, investments are needed (Greiler, 2007). To examine which crop and method of cultivation is best for the production of biofuel, more research in needed. In their paper, Peters and Thielmann (2008) state that natural resources are under attack on a global level when large-scale mono-cropping is expanded in order to produce biofuels. However, according to Greiler (2007), some negative impacts can be limited by sound agricultural practices, and arid and degraded land could benefit from the production of certain crops. Also, more research should be done on the potential decrease and avoidance of greenhouse gas emissions by substituting fossil fuels with biofuels.
Regardless, in order for biofuel to make sense, significant improvements should be made with regard to the efficiency of reducing fuel consumption of vehicles.
The costs and benefits of the production and use of biofuel are not priced in the market, therefore it is needed to make comprehensive and clear public policy choices (Greiler, 2007). In order for developing countries to benefit from biofuel production and use, participatory planning is needed.
NGOs and development agencies play a key role in ensuring the poor with benefits from the biofuel sector and the creation of a new market without increasing their vulnerable position (Greiler, 2007).
4.4.3. SWOT analysis for the production of bioethanol from corn in Tanzania
Strengths
● The production of corn for energy purposes in Tanzania can be produced on land that is unfit for the production of food, therefore there will not be a food vs. fuel competition.
● The production of the corn can be produced on land that is unfit for livestock grazing, therefore there will not be a livestock vs. fuel competition.
● Corn is a suitable crop for phytoextraction (Poniedzialek et al. 2010).
● Biofuel produced from corn has a positive net energy balance (Shapouri et al., 2002). ● The production of biofuel from corn comes with several by-products such as dried distillers
grains with solubles (DDGS), corn gluten meal (CGM), and corn gluten feed (CGF) which can all be used in other industries (Shapouri et al., 2002).
Weaknesses
● Starchy crops grown in a temperate climate generally require high fossil energy inputs and therefore show less greenhouse gas reduction (Farrell et al., 2006).
19 ● The production of corn requires fertilizers, pesticides, and high amounts of water (Rutz &
Janssen, 2007).
Opportunities
● In order to optimize the process of producing biofuel from corn, many research has emerged. ● In 2007, less than 10 percent of bioethanol production entered the international market, leaving
big potential to enter the market. According to Greiler (2007) a rapid growth in exports is to be expected.
● Tanzania has the opportunity to largely expand their rain fed crop production.
● It is very feasible that the bioethanol that is produced in Tanzania becomes highly competitive because of the current oil prices and the technological developments (Greiler, 2007).
Threats
● Greenhouse gas emission is not consistent which makes it difficult to make forecasts and consequent decisions (Greiler, 2007).
● Corn is the main food source in Tanzania. It is consumed by the majority of the households in both rural and urban areas (Arndt et al., 2010). If corn is being produced for the production of biofuel, this may lead to other farmers selling their crops for the production of biofuel instead of food. Which can result in a serious food vs fuel competition.
4.4.4. Conclusion of SWOT
Economic development in Tanzania could be enhanced by the introduction of biofuel production. In order to maximize the effect of the biofuel sector on the reduction of poverty in Tanzania the
productivity of smallholder farmers require improvement. In Tanzania, economic development is reliant on the agricultural performance. The establishment of a biofuel industry can create an opportunity to enhance the efforts of poverty reduction by revitalizing the agricultural growth and creating jobs in the rural areas.
There is a chance that the biofuel industry may not generate enough income for the poor to outweigh the rising food prices when resources are shifted away for the production of food to the production of biofuel. Therefore, concerns about food security might seem valid.
However, when fertilizer impacts and land clearing are not part of the process the environmental benefits of biofuel are overstated in comparison to fossil fuel. It is important to keep notice of the fact that the optimistic views on the potential of the biofuel industry as a way for developing countries to grow is based on the assumption that there is much surplus land in these countries that is available for the production of feedstock for energy purposes.
The issue that is most important is that of the competition between labour and land. Yet, food security is not only about the production of a sufficient amount of food within Tanzania.
In order to establish a successful biofuel industry in Tanzania, several public investments are needed which are in conformity with their national development plans.
Overall, the production of biofuel from corn could have significant benefits for Tanzania and could contribute to accomplish the country’s development objectives.
20
5 Discussion
Not all problems that are related to pollution of heavy metals are taken into account in this paper. Other factors that are affected by pollution are freshwater fish, livestock and crops. The toxic waste has several ways to reach and affect the human body, leading to certain health problems. With the use of phytoextraction the level of toxic waste will be reduced, the soil will be suitable again for growing crops or for cattle. The plants which are used for the phytoextraction will be used for the production of biofuel.
However, by conducting this study, it was found that the Mto wa Mbu region does not have a problem regarding contaminated soils; only nickel slightly transgresses the recommended soil content value (Table 1). That is positive for the local population and environment, but makes the
implementation of this project over there unnecessary. For now, a location can only be chosen through literature study. Then it would turn out that this project could be helpful in an area analysed by Yabe et
al. (2010), for example a region nearby a mine or along the coast of Tanzania, where soil contamination
are significantly higher.
But in order to implement this approach governments need to cooperate, stimulate and support a long term approach. This is why it is suggested to introduce political sciences to the topic. This
discipline could study political willingness to apply the phytofuel method and the stability of governing instances.
The implementation of this project in a region as Mto wa Mbu is also dependent on the population. It might be the case that the local population is dependent on the production of crops for income or food. Then, implementation of this project would do harm to the social aspects that are not analysed in this paper, but have to be taken into account when thinking about realising this project.
Additionally, it is recommended to study the cadmium contained in biodiesel as an end product since this is still unknown. Most studies in the contaminated soil section concerning human health were conducted in developed countries such as Sweden, Belgium and China. Large numbers of affected individuals in the studied populations did not show cadmium blood or renal values above the regulated values and were yet shown to be significantly affected by cadmium poisoning. It is therefore
recommended to re-assess the safe boundaries for cadmium in the biosphere, and then study volatilized cadmium values from industry and phytofuels.
The original lab proposal for this paper was declined due to safety reasons. However, the original lab plan can be found in the appendix. This experiment was proposed in order to study the viability of selected plants in the climatic conditions of our target region. It is recommended to perform this study in situ in order to determine cadmium uptake and plant viability.
21
6 Conclusion
The question this paper tried to answer was:
“To what extent can the phytofuel solution serve as a viable multi-problem solution to the
environmental, health and energy issues in the Mto wa Mbu region, Tanzania?”
It is difficult to answer that question, due to the fact this report lacks thorough research regarding optimal circumstances in which phytoremediation can be used. Even though not all factors that
contribute to the successful use of phytoremediation were fully analysed, the suggested approach forms a good and sufficient basis for further research. One of these factors could be for which contamination concentrations the plants are useful, for example. It was planned to have answers to such uncertainties after conducting the original, but cancelled, lab proposal. If more is known about how plants used for phytoremediation can be converted into an environmental friendly and sustainable energy source, this multi-problem solution can be suitable for implementation. The soil analysis showed that the location was not suitable for implementing this project. When it comes to toxicity, there is a negligible amount of Pb present in both soil samples. As for Cd and Ni the samples contain again low amounts and therefore will not have dangerous consequences for the population of the region (Muchiweti et al., 2006). So, by finding a contaminated location where this project could be the answer to the environmental
degradation and could influence health and energy issues as well, this multi-problem solution can be used successfully. Hopefully, this is the case since this is a subject studied quite intensely nowadays, phytoremediation will become a solution for environmental and health issues more regularly and by combining it with biofuel production will lead to an answer to the energy issue. For now, the SWOT analysis concludes that the production of biofuel from corn can have a beneficial outcome for the economy of Tanzania.
What this report also wanted to examine is the concept of multi-problem solutions and the process of finding such a solution. It turned out that it is possible to assemble several problems and find a single solution to tackle these problems, by investigating their common ground. This was only a single multi-problem solution, but the possibilities are endless. There is a wide range of problems that still needs to be solved, but there might be solutions that resolve several problems at a time. This interdisciplinary approach could accelerate the search to a more sustainable future.
22
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26
Appendix 1
Lab report
There are two soil samples, one taken from the upper soil layer in a riverbed and one from the upper layer between fields that are used for agricultural purposes (corn and rice). The samples are tagged as followed: the field sample is tagged as 2015/TAN/1 and the riverbed sample is tagged as 2015/TAN/2.
Heavy metal analysis
To determine the concentration of heavy metals in the soil, it can be dissolved in an acid called aqua regia, which is 37% hydrochloric acid and 65% nitric acid. Next, heavy metals can be detected using an ICP mass spectroscopy analyser. Before the soil can be added to the acid, it has to be prepared. This includes grinding the soil with the hand, then sift it with a sieve so it takes out objects bigger than 2 mm. The grinding helps breaking down aggregates into their original compounds. The sample taken from the river bed was dried at 100 degrees Celsius before it was grinded and sieved. Then a planetary ball mill was used to grind both soil samples to fine particles. These samples had to dry at 100 degrees Celsius for 24 hours. When the samples are dry, two times 250 mg per sample are weighted so both samples have a replica. There are also two blank samples for comparison. Then the acids are added to the six samples and after approximately an hour of soaking, the samples are placed in the microwave with the method USER002H. For another hour the samples are followed through temperatures of 220 degrees Celsius and a pressure of 75 bar. Next, the samples are transferred into each their own flask of 50 ml and purified water is added. Then it can be used for analysis with the use of the ICP mass spectroscopy analyser. The results were presented in mg/kg and later converted to mg/L for comparison with literature results. Table 1 and 2 show the average of the field and riverbed samples in mg/kg and mg/L.
Table 3: results of heavy metal soil analysis in mg/kg
Sample As (mg/kg) Pb (mg/kg) Cd (mg/kg) Ni (mg/kg)
Field <16 <12 <1,0 102,3
Riverbed <15,5 <11,5 <0,95 84,3
Table 4: results of heavy metal soil analysis in mg/L
Sample As (mg/L) Pb (mg/L) Cd (mg/L) Ni (mg/L)
Field <0,8 <0,6 <0,05 5,1
27
Organic compounds analysis
To determine the organic compounds in the soil samples, the samples are prepared by weighing two times an amount of about two grams per soil sample. First, the bowls are weighted in the analytical scale, so the weight can be determined at the end of the process, including the weight of the bowls. To make sure the change in weight of the bowls is taken into account, two bowls are weighted without soil samples in them. They will go through the same process as the other bowls (with soil samples). All six bowls are dried for 24 hours at 100 degrees Celsius before the process continues. Then, the samples are weighted again for 16 hours at 375 degrees Celsius in an annealing furnace. After that they are weighted again and then the percentage of organic matter can be calculated.
Appendix 2
When the first draw of this research was written the aim of this paper was to conduct a lab experiment. Due to the fact working with cadmium generates waste which is difficult to clean or store the original lab experiment was declined due to safety reasons. Nevertheless the aim of this experiment could be of significant value for this paper. The original plan therefore is added in the appendix so when further research is carried out this could be taken into account.
Original lab proposal:
A crop species will be selected that meets the demands of the sketched situation. Which means it needs to be able to extract cadmium from the soil and it needs to be edible. For this experiment corn will be used due to the fact it grows fast, is edible and can extract cadmium from the soil. Then, if our expectations are correct, twelve corn plants will be placed in soil with equal nitrogen, phosphorous and potassium content. This content will be favourable to the growth of corn so the whole effect of
cadmium concentration can be measured. The twelve plants will be divided into four groups. Then, we will contaminate the soil of three out of the four groups with a cadmium based soluble salt. One group will be contaminated with 5 mg/kg of soil (recommended maximum (Yabe et al., 2010)), the next with 7 mg/kg, the other with 9 mg/kg and the final group will remain uncontaminated to serve as our control group. Environmental conditions of the target area will be assessed with focus on average climate conditions. Climate conditions will be kept constant at these averages. When the plants are ready for harvest the soil will be tested for remaining cadmium content. Additionally, cadmium will be extracted from the plants to determine the cadmium uptake and concentrations in the plants. While the plants are growing, the conditions are regularly tested to make sure constants are maintained. Furthermore, spread over the time used for the lab experiments, the strengths, weaknesses, opportunities and threats of our new approach are assessed. This part of the study is planned according to obtained results from the lab experiment (e.g. the toxicity of contaminated plants etc.)
28
Application Form Lab Use for Interdisciplinary Project
Name(s)
(indicate who will do the experiments)
Hidde Nab Fleur van Crimpen Mabel Gray
Disciplines Ecology Earth Science Earth Sciences Subject/research
question
Using corn from phytoremediation for biofuels; A new approach
What? (Type of experiment)
We will contaminate the soil of three out of the four groups with a cadmium based soluble salt. One group will be contaminated with 5 mg/kg of soil
(recommended maximum (Yabe et al., 2010)), the next with 7 mg/kg, the other with 9 mg/kg and the final group will remain uncontaminated to serve as our control group. Environmental conditions of the target area will be assessed with focus on average climate conditions. Climate conditions will be kept constant at these averages. When the plants are ready for harvest the soil will be tested for remaining cadmium content. Additionally, cadmium will be extracted from the plants to determine the cadmium uptake and concentrations in the plants.
Why? (Aim of experiments)
We expect the results to show that corn can grow in all soils, including those contaminated with Cadmium. We expect the corn growing on the clean soil to grow the fastest. We expect that the corn will withdraw a significant amount of Cadmium from the soil.
Number of samples (if applicable)
Three concentrations of cadmium? Of which all three are repeated three times and a control group of three of which the concentration cadmium is zero. Twelve samples in total.
How much time needed in total?
