‘Eat your Waste’
A sustainable alternative to the waste management system of the
Science Park, Amsterdam, based on a cost and benefit analysis.
Student Major Number Supervisor & Tutor
Laurens Broeze: Biology 10657959 Myrte Mijnders,
Jasper Roosendaal: Biology 10550011 Kenneth Rijsdijk
Jan van der Kolk: Political Sciences 6082688
Anaïs Passera: Earth Sciences 10339825
Word Count
~6500 without headers and citations Date
22-5-2016
First of all, thanks to Myrte Mijnders for supporting us during our research. Your enthusiasm, relating to your position in Anna’s Tuin & Ruigte, was of great support to us. Also a thank you to Kenneth Rijsdijk, who kept our research aims real and small enough to conduct. We would like to thank Ewout Doorman, Kick Maurer, Wil van Zijl-Barbe and Jelle Warmenhoven for their liberated time, their willingness to help and their interest into our project.
0.2 Abstract
The Science Park campus of the University of Amsterdam (UvA) is planning to make considerable changes concerning the waste management system. Some innovative new methods are being discussed which would contribute to the sustainability of the faculty. In this research a new sustainable approach to the waste system on Science Park will be compared to the current waste system. Currently, biodegradable waste is not separated and is incinerated for energy. This research presents an alternative waste collection method where biodegradable waste generated by students and employees is digested to create compost, which will be applied and stored at proximity of the faculty in Anna’s Tuin & Ruigte or sold to third parties. The technical feasibility and sustainability of the transformation of waste to compost in the case of Science park are evaluated in comparison to the current waste management system. This is done by a cost and benefit analysis. The proposed sustainable waste system ‘Eat your waste’ is gaining popularity among UvA stakeholders as the composting process is a feasible and environmentally more sustainable option than the current waste management system on the Science Park area. Our analysis shows that our sustainable alternative is preferable over the business as usual scenario.
0.1 Acknowledgement 2
0.2 Abstract 2
1. Introduction 3
2. Study Area 5
2.1 Science Park area 5
2.2 Anna’s Tuin en Ruigte 5
3. Theoretical framework 6 3.1 Sustainability 6 3.2 Food Waste 7 3.3 Carbon Footprint 7 3.4 Biodegradable waste 7 3.5 Compost 8 3.6 Composters 10
3.7 Cost and Benefit Analysis 10
4. Methods 11
4.1 Composting process 12
4.2 ICOVA 12
4.3 CBA 13
4.3.1 Identifying CBA criteria 14
4.3.2 Cost/Benefit determination 14
4.3.3 Value, Standardisation, and Weighting 14
4.3.4 Ranking 14
5. Results 15
5.1 Science Park Waste 15
5.2 Processes of the waste management system 15
5.3 Criteria 17
5.4 CBA 21
6. Discussion 23
6.1 Visualisation new waste system 23
6.2 CBA 24
7. Conclusion 24
8. References 25
9. Appendix 29
9.1 Data Management Table 29
9.2 Alternative 30
Resources around the world are being used, and consequently global reserves are diminishing. One of the many challenges that need to be addressed to mitigate this problem is to make urban residents live in a more sustainable way. This challenge is likely to become only more pressing in the future as most of the projected population growth is expected to be concentrated in urban areas (Cohen, 2006).
An important aspect of life in urban environments is the management of waste. Cities are currently under great pressure regarding increasing waste material flows, since population density in many cities is high (Kennedy et al., 2015). This waste, if not recycled, makes up for a large loss of resources (Grizzetti et al., 2013). Food waste becomes a rising problem in urban areas as there is limiting space for the growing quantity of this waste (Cohen, 2006). The magnitude of this problem leads to the development of practical solutions. However, it is not within the scope of this project to perform research on a city level. This paper is going to identify and analyse the costs and benefits that implementing a biodegradable waste management system would have on Science Park Amsterdam in the Netherlands.
The current waste management of the city of Amsterdam, including Science Park, does not include separate collection of biodegradable waste. In order to initiate a sustainable waste collection system, it is necessary to transform the current system from a linear waste system into a circular waste system wherein no material or energy flows are lost. Biodegradable waste can be recycled by using it as a fertilizer, through the process of composting or digesting (Hermann et al., 2011). Thus far, biodegradable waste has been incinerated together with non-recyclable resources to generate energy (R. van Batenburg, personal communication, 21-05-2016).
Science Park Amsterdam could improve its environmental footprint with a small scale composting project on the faculty itself. The purpose of the proposed project ‘Eat your waste’ is to collect biodegradable waste separately to create compost out of this waste and to apply it onto the soil of a permaculture garden called “Anna’s Tuin en Ruigte” in proximity of the faculty. The aim of this research is to determine the costs and benefits of separating and reusing biodegradable waste as compost for the Science Park. However, we do not define costs and benefits only in quantitative monetary values, but also in qualitative values. This makes it possible to integrate multiple scientific disciplines in our analysis.
We will present a sustainable alternative (SA) for the current waste management system, or business as usual scenario (BAU). The environmental effects that the new management system will have, as opposed to the old strategy, will be analysed from a biological and earth scientific point of view.
However, the incorporation of a new waste management system also requires certain political and social incentives. Limitation of financial costs is important and the efficiency of governance should also increase, this requires support from all involved stakeholders. Ultimately, a Cost-benefit analysis (CBA) will show our results. This is a structured approach capable of comparing the current system with the sustainable alternative to determine overall preferences among them.
Because of the interdisciplinary approach, a relatively broad range of factors can be analysed at the same time, resulting in a more complete image than a mono- or multidisciplinary approach would yield. The research question is:
What are the costs and benefits on an environmental and political level of implementing a biodegradable waste collection system for Science Park, Amsterdam, opposed to the current waste collection system?
To answer this question, we will inquire several subjects as criteria for the effectuated CBA such as the current structure of the waste management system of Science Park, its cost and environmental benefits and the possible points of improvement needed to reduce the ecological footprint. In addition to this, the different composting processes are examined. In order to be able to test the achievability of the proposed project, several policies and stakeholders of Science Park were addressed to investigate the vision and opinion of people on changes of the waste system.
2. Study area
2.1 Science Park Area
Science Park belongs to the University of Amsterdam and consists of approximately 5000 students and 1500 employees. This amount of people is generating increasing waste material flows. Those flows are not seen as problems for some people, but as opportunities for sustainable recycling projects. Situated in the eastern part of Amsterdam, Science Park is a relatively new created area on which there is still a lot of free space available. Therefore, students participate in the sustainable development thinking processes of the faculty.
Science Park in this report is defined as all buildings that are establishments of the University of Amsterdam. These are the Dark green areas as seen in Figure 1.
2.2 Anna’s Tuin & Ruigte
In the coming years, an area adjacent to the Science Park (Red area indicated in figure 1) will be transformed into a permaculture with the name ‘Anna’s Tuin en Ruigte’ (Anna’s Garden & Wilderness). The construction started in 2016. Collected biodegradable waste from Science Park could be an optimal organic fertilizer for this area in order to create a fertile garden. Special biodegradable bins on the faculty where waste can be deposited facilitates the process where waste generated by students contributes to the creation of a fertile soil in the permaculture garden. This would allow efficient agriculture processes creating more fruits and vegetables. Ideally, the produced products from this garden could be used in the future in the Science Park kitchen and sold to students in order to completely engage a closed cycle without any loss of resources.
Fig. 1. Science Park Area. Map provided by CWI.
3. Theoretical framework
3.1 SustainabilityIn this research the definition of sustainability we have chosen to incorporate to is the one given by the World Commission on Environment and Development as: “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”(Brundtland et al., 1987). Inherent to this is the shift from a linear management (where used resources are thrown away) to a circular management (where resources are reused). Since linear management will keep losing resources as waste is thrown out, resources are likely to run out. Smart circular management will keep these resources in the system, limiting direct losses (Termorshuizen, 2004). Chemical elements such as phosphorus and nitrogen can be preserved if circular waste management is effectuated efficiently. A project relevant to the ‘Eat your waste’ case is the University of Lausanne, Switzerland. This university disposes their generated food waste by sending it to a farm at close proximity where it is used to produce organic fertilizers but also to generate electricity and biogas fuel for the farm itself and the surrounding community. The separation of biodegradable waste is also effectuated in the case of the University of Utrecht (UU), a comparable Dutch university (Universiteit Utrecht, 2016) where paper, wood and human waste are excluded. This demonstrates the successful achievement of a sustainable waste management system in the Netherlands.
In the 1990’s the concept of Green Urbanism emerged, with the principal theories being zero-emission and zero-waste urban design (Lehman, 2010). Green Urbanism describes any urban development that promotes social and environmental sustainability (Lehman, 2010). Lehman (2010) wrote a review study that summarized the 15 guiding principles of Green Urbanism. One of these principles is the principle of local and sustainable materials with less embodied energy. Key aspects of this principle are advanced material technologies and shorter or circular supply chains (Lehman, 2010).
The sustainable aspect of compost is its characteristic of being a resource generated from biodegradable waste. In general, it is a reusable, renewable resource. Originally an outflow, after a composting process, biodegradable waste is converted into an inflow that can be re-circulated in food chain. The ability of re-circulation, is the key property of compost that makes it fit to be an aspect of the Green Urbanism principle for local and sustainable materials with less embodied energy.
The green urbanism theory raises some points of criticism concerning the fact that composting is more seen as a source of energy by heat extraction instead of a useful source for agriculture. Confirmed by Lehman, the performance of compost as a soil conditioner is underestimated (ibid.). On a larger scale ,the opportunities of compost on agricultural soil application are enormous from an earth scientific perspective. Composting receives increasing attention among waste management strategies as solution for organic waste disposal with simultaneously quality soil maintenance.
3.2 Food waste
With the increasing population density worldwide and in the Netherlands, the increased generation of food waste is a serious problem. The largest concern by many stakeholders is the environmental impact food waste has such as increasing greenhouse gas emissions including methane and carbon dioxide (Mason et al., 2011). Inefficient food packaging is a source of abundant waste flows (Mason et al., 2011). However, several waste flows such as biodegradable waste is seen as part of the solution to linear waste management systems. The economic and environmental viability of food waste disposal systems is growing in concern and the interest in food waste as a resource input to agriculture gains popularity among stakeholders. The abundance of food waste is a serious problem which needs to be tackled from a bottom up approach.
3.3 Carbon footprint
The contribution of an actor on greenhouse gas emissions is represented by the actor’s “carbon footprint”. The carbon footprint of the faculty on Science Park could be reduced by creating a more sustainable waste management system, with less emitted greenhouse gases. Recycling is an effective method to contribute to the latter. The distribution and usage of food, in addition to the resulting waste management, all require energy. This energy is mostly originating from fossil fuels which is a significant source of greenhouse gas emissions (Hermann et al., 2011). The carbon footprint of the waste system on Science Park could be minimised by eliminating transportation processes (by effectuating local composting). In every stage of the waste cycle the environmental impact can be reduced by implementing innovative new recycling systems. Material management through resource conservation refers to how people manage material resources as they flow through the economy from reuse of materials to disposal (ibid.). The ‘Eat your waste’ project promotes waste management that serves human need by using and re-using resources productively and sustainably minimizing the amount of material required and the associated environmental impacts.
3.4 Biodegradable waste
Within this research, biodegradable waste is defined as all waste that are remnants of food products. In contrast to the common definition of biodegradable waste, this excludes paper, wood, and human waste, since these are either already collected separately or, in the case of wood, only present in relatively small quantities.
Furthermore, swill is a terminology used for a common type of biodegradable waste present at the Science Park area. It is defined as (wet) kitchen remnants or food remnants such as peels (potato peels, fruit peels, inedible parts of vegetables, nutshells, tea bags, egg scales, etc.). These are easily compostable waste products.
Biodegradable waste transformed into compost is the final generated product of the proposed project as further cropping opportunities in Anna’s Tuin & Ruigte are still to be determined. Compost can be obtained by two different processes: composting and digestion. 3.5 Compost
Through time, the practice of composting has consisted of piling organic materials until the next planting season (Diaz & Bertoldi 2007). By then, the deposited materials were decomposed to the extent where it is ready for fertilizing the soil. The difference with present day composting is the modernized process. Modern composters stimulate the decomposition process of the biodegradable waste through a series of treatment steps. Nowadays, this is occasionally done to accelerate composting processes for industrial reasons in order to manage surplus biodegradable waste materials. The service of waste as compost can contribute to circular and sustainable waste management.
Compost is rich in organic matter and an important source of nutrients for plants (Gallardo-Lara & Nogales, 1987). The quality of compost depends completely on the waste composition and therefore it is important to address importance to the type of input of waste materials, especially on small-scale composting processes(Regenstein, 1999).
The main effect of compost on a soil is the promotion of microbiological activity, which in general is related to soil fertility (Frankenberger & Dick, 1983). The soil microbial biomass is responsible for the mineralization of the important organic elements (Carbon, Nitrogen & Phosphorus) on which plants grow. Thus, indirectly, compost can be responsible for the presence of plant essential nutrients (Garcia-Gil et al., 2000). Figure 2 shows the results of a study performed in Spain comparing the properties of standard fertilizers to compost. The results of the study indicated that compost is a significantly feasible alternative for manure or mineral fertilizer which are commonly used (Garcia-Gil et al., 2000). However, screening the compost for heavy metals and other potential pollutants which are often encountered in municipal waste is essential before application (ibid.).
Fig. 2. Characteristic of soil, compost and manure used in the study of Garcia-Gil et al. (Garcia-Gil et al., 2000).
Compost consists of a lot of beneficial properties such as long term carbon storage (Hermann, 2011). As intensively cultivated soils suffer under carbon losses, using compost as a soil conditioner to counteract these losses can be of value. Therefore, compost supports humus formation on the topsoil which is difficult to accomplish with artificial products (Hermann, 2011). In addition, compost and digestate improve the soil structure by increasing the organic matter content. Organic matter improves several soil properties, including water-holding capacity, hydraulic conductivity, bulk density, fertility, and erosion resistance (Carter and Stewart, 1996; Zebarth et al., 1999; Franzluebbers, 2002) (see figure 3). This allows nutrient transportation which is beneficial for autotrophic organisms such as fruits and vegetables.
Fig. 3. Property tree of compost as natural fertilizer
3.6 Composters
Stimulation of decomposition processes of generated biodegradable waste can be effectuated by specific containers wherein the composting or digestion process could take place. There is quite a reasonable amount of free space on the Science Park to place an extra container. According to Kick Maurer (Personal communication, April 1, 2016), there is sufficient space just behind the area where the different waste types are already sorted and ready to be picked up.
3.7 Cost and Benefit Analysis
Cost-benefit analysis (CBA) is considered to be the most comprehensive and theoretically sound form of evaluation on an economic level (Robinson, 1993). In the last 50 years it has been widely used in different areas of economic and social policy in the public sector to aid decision making. CBA can be used for any situation requiring evaluation of choice. Over the last decades it also gained popularity in evaluating environmental case studies (OECD, 2016). However, CBAs are not necessarily precise. Often, factors include estimates, especially qualitative factors. For this research, costs are defined as factors that cost money, are harmful to the environment, negatively impact social structures, are inefficiently on a spatial scale or in technological aspects. Benefits are defined as acquiring money, helping environment and not interfering or positively contributing spatial and/or technological aspects. In terms of sustainability this means that benefits increase sustainability in line with our definition of sustainability and the principles of green urbanism related to our research and that costs have zero or negative impact on sustainability i.e. no change in sustainability is considered as a lost opportunity and thus a cost. CBA is preferred over other analysis techniques. Since a CBA has no prescribed standard definition and does not refer to a specific approach or methodology it can be easily adapted to the specific demands of this research project making it more feasible than other comparing techniques such as a Multi-Criteria Analysis (MCA) which framework has a more strict structure. A key
aspect of CBA are its criteria. In any scenario where different options or choices are evaluated, certain criteria are bound to the different options. These criteria can be seen as a cost or a benefit and can be quantified according to their specific units, However, qualitative factors are hard to quantify and will be given value qualitatively. Criteria are constructed as an end product of an objective tree.
Objective tree
An objective tree is a systematic approach to identifying criteria of a CBA. It is a visualisation of the main goal that is trying to be achieved by different options. These options are evaluated by the CBA and the requirements that need to be met in order to realise said options are the criteria exposed to evaluation. How an objective tree is constructed is explained in the methodology.
CBA Criteria
In general, criteria are categorized as economic, social, environmental/ecological, spatial and technological. Inherently, this makes a CBA interdisciplinary. The following table (figure 4) defines the goals of criteria in terms of sustainability.
Economic goals Social goals Environment/Ecologi cal goals
Spatial goals Technical goals Increase economic activity, infrastructure Maintaining/incr easing surrounding environment (appeal and habitability) Increasing ecological efficiency of resources/materials → sustainability Maintaining/inc reasing cultural/historic al sites or elements Increase energy efficiency Maintaining/increasi ng logistics/carrying capacity Maintaining/incr easing Employment and labour participation Maintaining/increasing nature and its values in direct surroundings) Maintaining/inc reasing spatial coherence and differentiation Balance consumption and supply of resources/energy Minimizing costs (i.e. construction and exploitation) Maintaining/incr easing the variety of recreation (i.e. Anna’s tuin en ruigte) Maintaining/increasing the status of (endangered) species Minimizing CO2 emission Maintaining/inc reasing future options for expansion in case of possible lack of space Increase safety and liability of used technology
Fig. 4. Table of the different goals per category (Gilbert, 2016).
4. Methods
The objective of this study is to draw new conclusions on the comparison of two waste collection systems of Science Park. Firstly, a literature study was performed to determine how the new biodegradable waste management system could be constructed. The literature
study focussed on the optimal way to transform biodegradable waste into compost, how the compost is best preserved and to what extent the created compost is applicable on the soil.
Next to the literature study, a good amount of data was obtained by several interviews with stakeholders who are in a way related to the waste system of Science Park or Amsterdam.
The quantities of biodegradable waste generated on Science Park can be calculated with data from a report of IVAM (2015). This report was directed by the Policy Advisor on Sustainability and Innovation of the University of Amsterdam (UvA), Ewout Doorman. Since Ewout Doorman is a specialist in the field of waste management on the University of Amsterdam, we interviewed him for our project (Doorman, E., personal communication, March 7, 2016). The questions asked concerned the aspects of the current system that lack in sustainability and efficiency and to what extent mitigation could improve these aspects. Interviews with other stakeholders of the UvA waste management system (e.g. Kick Maurer, Arbo & Milieu FNWI) were conducted in order to determine how the alternative waste management system should look like.
Another source of information was the UvA’s Student Council. The Council has been actively trying to realize a biodegradable waste separation system, though plans continue being postponed or cancelled. The council has agreed to provide us with information regarding the current collection system, in turn we can share the results of this report to advance the process of implementing the separate waste collection.
After proposing our biodegradable waste management system, a quantitative study was performed, which examined a specific number of improvement points. A cost and benefit Analysis was performed. With the CBA we compare the current waste collection system on Science park with our proposed one in our research. A CBA describes the structured approach of the current system and is used to determine preferences among alternative, more sustainable, options (UNFCCC, 2016).
This type of analysis is useful for cases where a single criterion approach is not sufficient, especially where environmental impacts cannot be assigned to monetary values. Environmental, technical & economic criteria are used to evaluate several waste alternatives. The output of the CBA visualises a ranked overview of these alternatives. 4.1 Composting process
Different characteristics of compost and the composting process were studied and different methods compared in order to identify the optimal composting method in terms of time, space and money. In order to determine the optimal conditions for biodegradable waste to transform itself into compost or digestate at close proximity of Science Park, several theories needed to be understood. It is necessary to determine if composting or digestion processes are more suitable for such a small scale project. This was be done by a comparative literature study focusing on the advantages and disadvantages of composting and digestion processes. The most realistic outcome will serve as advice which helps choosing the right company (e.g.) providing composting containers) to collaborate with.
4.2 ICOVA
ICOVA is the waste processing company used by the Science Park area and other facilities of UvA located in Amsterdam. They are a company of a sustainable nature and their aims and goals are often aligned with the principles of sustainability we would like to enhance at the UvA Science Park by introducing a biodegradable waste management system and a more sustainable approach to the current waste management system.
Subsequently, ICOVA provides its customers with a number of options regarding the use of applying composting to the customers’ waste management system. One of these options is the rent of Oklin compost machines (distributed by Ecocreation in the Netherlands). Because the rent of these machines comes with a guarantee of fixing broken machines within 24 hours after an error, using these machines would be a reliable and convenient option of composting for Science Park facilities.
Due to the fact that data about the waste streams of Science Park was not available at the start of this research, we went to visit ICOVA to determine how much biodegradable waste is produced at the faculty. The photo below shows our visit to ICOVA.
Fig. 5. Our visit to ICOVA. 4.3 CBA
In our research we want to perform a CBA on two scenarios, business as usual and a proposed sustainable alternative. The CBA analysis provides an opportunity to evaluate the two scenarios and will provide valuable aid in making a decision on which scenario is preferable. In the next section of this research report, the four steps of performing the CBA will be comprehended, ultimately followed by the results in which the CBA of this research will be presented.
The process of performing a CBA is divided in four essential phases (Janssen & Gilbert, 2016). First, a number of criteria must be defined which are relevant to compare for the two scenarios. These criteria must be defined and given a value. Thirdly, when all values have been assigned, the sum of costs will be subtracted from the sum of benefits and this will yield a certain Net Present Value (NPV = ΣB - ΣC) for the two scenarios. All these values and sums including the eventual NPVs of both scenarios will be presented in a graph. A
smaller NPV ranks lower than a higher NPV. By this logic certain scenarios have a higher ranking than others and are therefore a more preferable choice.
4.3.1 Identifying CBA criteria
The first of the four essential steps in performing a CBA is identifying and describing the criteria for evaluation. One way to do this which has been generally agreed upon is by means of an objective tree. An objective tree is characterized as a structure of three main aspects. Firstly, the objective, in our case increased sustainability and creating a sustainable approach for the waste management system of the Science Park area.
Secondly, the requirements in achieving this, which for a sustainable scenario as proposed in this research are minimizing costs, maximizing quality of renewable product and the application of it, minimizing environmental effects (soil degradation, greenhouse gas emissions). The final aspect are in itself the criteria that play a role in meeting these requirements. Essentially, by generating an objective tree for a specific scenario, the relevant criteria are directly identified as an output of the objective tree. In the Results section of this report the objective tree we constructed for our project is presented.
4.3.2 Cost/Benefit determination
Once criteria are constructed, they must be judged as being a cost or a benefit and assigned accordingly. Assigning criteria as a cost or benefit must be in sound with given definitions of costs and benefits.
4.3.3 Value, Standardisation, and Weighting
The next step of the CBA is assigning a value and subsequently standardizing these values. Normally, values of a CBA are exclusively expressed in monetary units. However, to cover all aspects of the specific scenario in this project we will also integrate non-monetary values. Therefore In this research we will eventually assign every criteria, qualitative or quantitative, with a number from 1 to 10. This analysis strategy does not violate the basic principles of a CBA and is a legitimate way of coping with qualitative factors (Janssen & Gilbert, 2015). We choose to do this by giving each criterion a value on a scale of 1 to 10 based on the information we gathered in our research. 1 Being low and 10 being high. Consequently, these values are assigned a weighting according to their relative importance. This is done subjectively. This weighting is performed by assigning a weighting factor which is a fraction of 1. All criteria are assigned a fraction and combined, all fractions add up to 1. Standardized values are the result of the assigned value from 1 to 10 multiplied by their weighted factor. Finally, a Net Present Values (NPV) of the scenario can be calculated. This is done by subtracting costs from benefits.
4.3.4 Ranking
The weighted scores of each criterion will be represented in a structured graph. They will be placed in order of their score and on whether they are a cost or benefit. Eventually the NPV value of the two scenarios are placed in another graph, one graph leading from the other. Based on these results a conclusion can be made on which scenario is preferable, business as usual or the sustainable alternative.
5. Results
5.1 Science Park Waste
The total amount of residual waste produced at this location is about 172 tonnes per year (+/- 10 tonnes). Of this residual waste, about 6 tonnes consists of swill (biodegradable kitchen waste) (Warmenhoven, J., personal communication, May 2, 2016) which could easily be separated at the source in the kitchens of Science Park. For the remaining 166 tonnes, a sample has been taken of about 2 cubic metres. Subsampling this batch gave us an estimate of 15-20% biodegradable waste, which mostly derived from the greenhouse of the UvA. Because of the small portion of biodegradable waste in ‘normal’ residual waste (i.e. waste collected in public containers throughout Science Park), we have a choice to make whether or not it is valuable to separate this waste flow. If the normal residual waste is to be separated, there will be a dependency on the students’ ability and willingness to separate biodegradable waste. This, together with the monetary costs involved in introducing new garbage bins and the relatively small gains in terms of biodegradable waste separated, lead to the choice that separating normal waste is not worth the effort. The alternative is to only separate the major biodegradable waste flows (swill and greenhouse). This alternative has been evaluated in our CBA analysis.
Fig. 6. The sampled waste separated during the ICOVA visit. 5.2 Processes of the waste management system
After the comparative literature study between different composting processes, the following results were obtained.
Aerobic composting
The aerobic composting process requires oxygen to decompose organic matter (Burge et al., 1981). The by-products are heat, water and carbon dioxide. The heat produced, in contrast to anaerobic processes, is sufficiently high to eliminate harmful pathogens and supports the growth of beneficial bacteria (Smet et al., 1999). Aerobic composting is a faster process in comparison to anaerobic digestion, usually 8-10 days if performed outside by which there is no leachate produced. It seems as if aerobic composting is a better option than anaerobic digestion due to its time efficiency. Nevertheless, there are some
disadvantages. Aboveground compost storage is not recommended in populated areas (such as Science Park) due to undesirable released odours in its surroundings (Hermann et al., 2011). In addition, aerobic composting requires more labour as compost piles need to be frequently turned over to aerate the compost (Hermann et al., 2011).
Anaerobic composting
In contrast, anaerobic composting of organic waste materials is a process that does not require oxygen and proceeds in the presence of anaerobic microorganisms (Burge et al., 1981). The process is characterized by strong odours and the amount of heat generated is not sufficient to kill plant pathogens and weeds which is a disadvantage for the hygiene of the compost (Boulter, 2002). To overcome this, artificial heat is occasionally added. According to Moller (2012), the waste treated by digestion comprises three different fractions. The biodegradable organic fraction (kitchen scraps, food residues, grass & tree cuttings) which this projects focuses on followed by the combustible fraction (lignocellulosic organic materials) and the inert fraction (glass, metals, stones, sand etc.). The combustible fraction is not sufficiently appropriate for anaerobic digestion as the lignocellulosic materials do not easily degrade without oxygen. Therefore, this fraction should be used for energy instead. The inert fraction causes a problem prior to digestion and has to be removed before the process otherwise the digester volume will increase (Moller, 2012).
It is thus important that criteria concerning waste separation and monitoring of compost are clearly understood before creating an input of contaminants into the food chain through affected soils. The operating parameters must be monitored in order to enhance microbial activity and its safety. In figure 7, the pros and cons of anaerobic digestion against aerobic composting are presented.
Containers called composters from a Dutch company ICOVA, which are available for use on the Science Park area, uses a modified composting process which contains both aerobic and anaerobic elements. A great advantage is that the consulted company which provides Oklin composter containers provide material that could effectuate anaerobic digestion within 24 hours while there is some presence of oxygen. A small hole is the source of air through which the created heated air by the composting process can escape the container through a biological filter (Oklin, 2016). This allows the process to be safe and quick. Consequently, it seems that the fused process of aerobic as well as anaerobic is the main option for the alternative sustainable approach. A further elaboration on the so called ICOVA ‘Oklin composters’ will be elaborated later in this report.
Reusing resources through composting could contribute to the transformation towards a circular management cycle which is important to avoid unnecessary losses of natural elements.
For Science Park, it is thus more effective and feasible to create compost by the process proposed by the Oklin container which means several options have to be taken into account such as the provision of space and composting containers to effectuate the composting process at close proximity.
5.3 Criteria
The following criteria were obtained based on the outcome of the objective tree.
Fig. 8. Objective tree. Political
Feasibility
Feasibility is an important criterion to take into account. It is defined as how possible or doable it is to implement a scenario given its properties. This is dependent on multiple factors, for this research it involves the questions, Is there enough waste for composting?
Are there enough employees to collect separated waste, are there political aspects to be addressed such as licenses, permits or contracts that need to be revised or requested, are there spatial limitations. Of course, In business as usual (BAU) feasibility is not questionable since it is the present reality of how waste is managed. Therefore it scores a 10. However, the feasibility of implementing the sustainable alternative (SA) is quite high as well. Based on the calculation of Ecocreation, 71 kg of biodegradable waste (20%, which is in sound with the estimation our research team made during the visit to ICOVA) a day is created at Science Park to feed a composter with a 75 kg a day capacity. This implies that there is enough waste to be composted. Biodegradable waste is already collected separately at the kitchen and the greenhouse which is where the majority of biodegradable waste is expected and where the focus on collection is placed. Hence, no extra labour is needed for the separation. Extra labour would be expected for the individual transport of the collected waste to the composter. The composter can be provided by ICOVA, this implies no change of contract is required. Installing such a composter does not require any additional permits, and according to Kick Maurer (Personal communication, April 1, 2016) there is enough room to install a composter implying no spatial limitations. Everything taken into account, SA scores a 8. The weighting factor of feasibility is 0.25.
Environmental
The environmental impact of decentralised waste collection systems is analysed including soil fertility effects of applying locally produced compost using ICOVA containers. In order to propose a CO2 efficient waste management plan, the carbon footprint of the ICOVA Oklin composting containers was questioned using data retrieved from interviews. The only released CO2 from the containers is similar to the amount of CO2 released in the atmosphere if the biodegradable waste was directly deposited on the area behind the Science Park. The emissions differ per content of the containers unless the same amount of kg is added every time. Nevertheless, according to Servan Kreher, owner of Eco Creation, the CO2 released by burning such as cars or other engines is not the same CO2 as released by composting which is phrased ‘natural CO2’ which does not have a significant environmental impact. This leaves room for critics as both those natural and artificial CO2 will accumulate together. Natural CO2 is said to add and remove CO2 to keep a balance, while artificial CO2 is added without removing from the atmosphere which creates an excess of CO2 no matter its source (UNFCCC, 2016).
However, our proposed system would consume considerable amounts of electrical energy. This energy consumption roughly equals 1,5 Dutch households’ energy consumption. The UvA uses mostly renewable electricity (UvA & HvA, 2012), meaning that most energy consumed will not directly contribute to an enhanced greenhouse effect. Nevertheless, the energy consumed in the process could alternatively be used for other energy-consuming actions which are now using fossil fuelled electrical energy.
The GHG emissions presented do not integrate the full range of possible GHG emissions from compost. A small amount of nitrogen in compost is volatilized and released as N2O when applied on the soil. N2O emissions are estimated to be less than 0.04 MTCO2E per wet ton of compost (EPA, 2008).
Carbon emission
One of the environmental criteria is carbon emission. Changing waste management can affect the carbon footprint which bears consequences for the environment. The less CO2
during this process CO2 is emitted. On the other hand, in the SA scenario, biodegradable
waste is reused and processed in a composter to create compost. This also releases CO2 to
the environment. However, the composter releases CO2 of the short cycle. Basically, this
means that it is not as harmful to the environment since it does not partake in the long-term greenhouse effect. Additionally, in the SA, biodegradable waste is not transported to ICOVA in the dock area. This also reduces the carbon footprint of Science Park Area.
Another essential aspect of the carbon footprint for this research project is the reduced CO2 emission when using compost as a fertilizer instead of artificial fertilizer. The
main ingredient of artificial fertilizer is phosphorous which is a limited resource on earth. Its mining and transporting processes emits a lot of CO2 . Not only for the use on Anna’s Tuin
en Ruigte but also for individuals receiving free compost from Science Park converted biodegradable waste. Not all the compost will be used for Anna’s Tuin en Ruigte, therefore it is available for free at Science Park for any interested parties.
We assigned a score of 8 to BAU and a 4 to the SA. The weighting factor for carbon emission is set to 0.10.
Soil depletion
Compost, in contrast to artificial fertilizer is a sustainable alternative since it excludes the necessity of valuable limited resources, transport of artificial fertilizer, costs of purchasing and maintaining soil, prevention of leaching and the coping environmental damages while at the same time providing similar or sometimes more nutrients to the soil available for plant growth. In addition compost is better in sustaining water holding capacities of soil and is also efficiently applicable. The compost created by Oklin composters is very concentrated and rich in nutrients, it has an advised compost to soil ratio of 1:6. Everything considered the benefits of reusing biodegradable waste as compost score good in terms of sustainability.
We assigned a score of 7 to BAU and a 2 to the SA. The weighting factor for soil depletion is set to 0.15.
Technology
The purchase and instalment of the Oklin composter by ICOVA is a main aspect of technology change for the SA and is a cost. After determining how much biodegradable waste is being produced at the UvA Science Park, Ecocreation (ICOVA’s supplier of the composter) gave us a cost and savings indication. The complete costs of installing a suitable composter at Science Park will be €17.569,18. According to this indication, the energy consumption of the composter will result in energy costs of €476,39 per year.
Science Park pays ICOVA to dispose its waste. In the SA, the residual waste of Science Park will decrease, resulting in less costs made to ICOVA to process the residual waste. There is also a national tax on residual waste. The money spent on taxes will therefore decrease in the SA as well. Another consequence of installing a composter is that Science Park will produce compost. Anna’s Tuin & Ruigte will not have to purchase artificial fertilizer, and neither will the students and employees that will use the rest of the produced compost since it is not produced for monetary aims.
Of course, these costs are not of the issue in the BAU, any costs currently flowing to ICOVA for the waste management are seen as baseline costs and the extra costs of the SA are in relation to this baseline. Based on calculations from Ecocreation, the return on investment is 4.5 years. This is calculated by dividing the yearly income by the initial investment. The initial investment equals the cost of purchasing and installing the composter
by ICOVA of €17.569,18. The yearly income is calculated by subtracting the yearly energy costs of €476,39 from the saving on waste processing costs of €4.400.
We assigned a score of 2 to BUA and a 8 to the SA. The weighting factor is set to 0.2.
Social Image
Actively separating and composting biodegradable waste in combination with Anna’s Tuin en Ruigte project gives the opportunity for Science Park area and UvA to get a sustainable reputation. A good reputation has intrinsic value for any university, besides that, an image reflecting sustainability can positively affect cooperation with third parties such as other universities, institutes providing grants and companies for research.
Currently the image of Science Park does not reflect sustainability to an extent that is preferable for an institute with an exemplary role. There is plenty of room for improvement in the area of sustainability. Image is a qualitative factor, its score and weighting factor is subjective and has been determined by a weighted judgement of this research group. Image in BAU scores a 3 and in SA a 7. Its weighting factor is 0.15. .
Sustainable behaviour
The last criterion is sustainable behaviour, presuming all the positive side effects of reusing biodegradable waste as compost mentioned in the other criteria, the SA will promote
sustainable behaviour among individuals at Science Park area and surroundings. Especially when the motto of Eat your Waste is realized and crops grown in Anna’s Tuin en Ruigte are used in the kitchens of Science Park. In contrast to BAU this will be an increased amount of promotion. Inherently, the promotion of sustainable behaviour eventually increase
sustainability itself. Sustainable Behaviour is considered a benefit. In the CBA, BAU scores 2 and SA scores 9. The weighting factor is 0.15.
5.4 CBA
Fig. 10. CBA Table.
6. Discussion
6.1 Visualisation new waste system
The new waste collection system requires collaboration with the Dutch company ICOVA, which provides composting containers that could be delivered to the faculty of Science Park. After a few interviews, we managed to obtain some essential information regarding the provision and feasibility of those containers at Science Park. The separated biodegradable waste will go through a fast digestion process in an Oklin composter before being delivered at the neighbouring permaculture Anna’s Tuin en Ruigte. Essential in the achievability of the new waste system is the amount of generated waste and to what extent this compost will cover Anna’s Tuin en Ruigte as application of compost is not necessary all year long. The surplus of compost could be distributed among students and employees, or to third parties. It is not our intention to commercially sell compost.
Once vegetables are planted on the generated compost, students and employees of Science Park will gain affinity with the possibilities of their food waste, creating sustainable awareness.
Oklin Composters
The composters ICOVA uses and would install at Science Park are Oklin composters. No extra permits are required to obtain permission to install a container on the Science Park area. The Oklin composter is easily manageable as all biodegradable waste can be inserted (e.g. food waste, garden waste, teabags, coffee grounds, etc.). In addition to this, if a shredder engine is present it is even possible to process biodegradable coffee cups and other food packages (ratio: 75% biodegradable waste & 25% disposables). It is not harmful for the compost product if some plastic, metal cutlery or other non-biodegradable product by accident ends up in the Oklin machine. The composter needs to be emptied once a week. The process is quite efficient and fast, until 85% of the waste input in the Oklin compost is converted into compost within 24 hours.
ICOVA provides a large range of different products with different sizes with the following input capacity: 25 kg, 75 kg, 125 kg, 250 kg, 800 kg and 1350 kg per day. To take the smallest machine (25 kg) into consideration, only 15-25 kg a day have to be inserted. If this is not the case, the bacteria would enter a sleep mode after a certain amount of time until new food waste is inserted. Concerning Science Park we can conclude that the second smallest composter, the GG-30s, would be suitable for use on UvA Science Park. Its input capacity is 75 kg waste per day, 30 tons per year. It converts the input waste into compost within 24 hours, reducing the waste on average by 80-90%. This 80-90% of initial mass is converted to water and CO2, and is made completely odourless through nano-filter technology. The CO2, which is a greenhouse gas, is part of the short carbon cycle, meaning no fossil fuel is burned and no additional greenhouse effect takes place. This means the process is relatively clean, although for its power supply fossil fuel might be used. The average power consumption is 350-510 kWh per month (Oklin, 2016).
Fig. 13. Composting process of an Oklin composter (Oklin, 2016).
6.3 CBA
Monetary gains
Monetary gains are achieved through multiple sources. First of all, the digestion tanks reduce the biodegradable waste mass by 85%. This means that even if the digestate was still to be thrown out, the UvA would save 85% on its biodegradable waste collection costs. Our estimated 15-20% of residual waste being biodegradable would make this a decrease of about 25,5 tonnes of waste per year. Since the residual waste tax is about €13.- per tonne, this would make a profit of about €330,- per year. Implementation of the new system also means that Anna’s tuin en ruigte is not dependant on fertilizers from other sources, and can freely use our own compost.
Even though we have tried to create a complete image, several factors have not thoroughly been taken into account. For example, other buildings besides the UvA’s building on Science Park may be interested in joining up. This potentially reduces the costs per tonne of processed waste. We have however not looked into this.
7. Conclusions
Places where food is consumed can make a difference in the way food waste is managed. Kitchen and greenhouse waste on Science Park make up a significant part of the total biodegradable waste produced at the location. The biodegradable waste abundance starts to create environmental concerns and circular waste management systems are necessary in order to limit the loss of valuable resources.
To tackle this problem from a bottom up approach, the small scale project ‘Eat your waste’ was evaluated on the sustainability of its waste management system. Theoretical and methodological insights from different disciplines have been integrated in every section of
this report. The evaluation is done by comparing the pros and cons of the proposed system by a cost-benefit analysis.
The implementation of separating biodegradable waste and using it as fertilizer by means of digestion processes with the help of Oklin containers is more sustainable than the current waste collection system. The elaborated waste management proposal in collaboration with ICOVA and Anna’s Tuin & Ruigte is economically feasible, time efficient, achievable and ecologically responsible. As a faculty, it is important to become proactive on green issues as sustainable university rankings are growing in prominence and students state more importance on environmental responsibility.
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9. Appendix
9.1. Data Management Table Discipline &
subdiscipline
Theory Concepts Assumptions Insight into your
problem Earth sciences,
Biology & political science Specialisation: Sustainable megacities Subdiscipline: Waste management system
The waste collection system on Science Park is inappropriate in terms of sustainability. Inappropriate waste management
systems influence the quality of the environment. Small scale composting is sustainable Digestion is not suitable for compost Pathogens develop easily during digestion Small scale composting contributes to green urbanism Recycling Sorting of waste Composting Digestion Sustainability Compost is a good (partial) substitute for artificial fertilizer. Waste generated compost could serve as a natural fertilizer. Recycling reduces the amount of garbage wasted. Dumped waste is lost energy and resources. Policy is a driver for change. Digestion needs to be precisely monitored to avoid harmful viruses Composting is closing the recycling loop Composting is efficient but contains some law related restrictions If Science Park could put more effort in recycling and sorting its waste, it will put less strain on the environment, while we retain more resources. Science Park is a suitable experiment area for a small scale composting project. Composting and digestion need to be compared to conclude which technology is optimal on Science Park.
9.2. Alternative: separate all student waste
An additional option to be considered is the introduction of new types of garbage bins on the faculty where students and employees can separate their waste through different compartments within a same garbage bin. If there is a clear explanation on the bin about what is and isn’t allowed to insert in that bin, students should be able to contribute to the waste selection by themselves (see figure x). With the introduction of new multi-type bins on the faculty, users will obtain more affinity with the ‘Eat your waste’ project. The story of their waste playing an active role in the permaculture of Anna’s Tuin en Ruigte could be clearly explained on the bin itself by eye-catching posters, this way more actively engaging individuals to partake in properly separating their garbage. The following figure simulates the concept of multi-type bins.
However, students and employees need to be well informed or trained on how to use these bins. If users deposit the wrong type of waste into an organic waste bin, cross contamination could occur. This would render the content of that bin unsuitable for composting. Another issue is that we learned from the waste sampling at ICOVA, that the students do not create a lot of biodegradable waste.
From Wil van Zijl we learned that the multi-type bins used at the Roeterseiland Complex cost €2000 each. And these do not include a designated bin for biodegradable waste yet. Kick Maurer (Personal communication, April 1, 2016) told us that if the Science Park is going to implement multi-type bins, they want the same kind of bins as at the Roeterseiland Complex, due to uniformity. Thus, there is no opportunity to create cheaper bins.
