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Project Report – Quantifying and reducing organic waste by providing bins in James Cook University staff lunchrooms Funded by the TropEco Action for Sustainability Grants Program
Produced by Max Burns ([email protected])
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1 Table of Contents
Contents 1 Table of Contents ............................................................................................................................ 2
2 Highlights ........................................................................................................................................ 4
3 Abstract ........................................................................................................................................... 4
4 Introduction: ................................................................................................................................... 5
4.1 Aims and Objectives ................................................................................................................ 5
4.2 Project Overview ..................................................................................................................... 5
4.3 Background Information ......................................................................................................... 5
5 Staff Engagement and Communication .......................................................................................... 6
5.1 Survey and meeting outcomes ............................................................................................... 6
5.1.1 Composting interest and participation ........................................................................... 6
5.1.2 Staff Comments and Concerns ........................................................................................ 7
5.2 Behavioural change ................................................................................................................. 8
5.3 Signage .................................................................................................................................. 10
5.4 Feedback survey responses .................................................................................................. 11
6 Logistics ......................................................................................................................................... 12
6.1 Organic waste bins and biodegradable liners ....................................................................... 12
6.2 Composting method ............................................................................................................. 12
7 Life Cycle Analysis ......................................................................................................................... 15
7.1 Goal and scope ...................................................................................................................... 15
7.2 Functional unit and system boundary .................................................................................. 15
7.3 System characterisation and assumptions ........................................................................... 15
7.3.1 Food waste .................................................................................................................... 15
7.3.2 Transport ....................................................................................................................... 15
7.3.3 Landfill ........................................................................................................................... 16
7.4 Life Cycle Impact Assessment ............................................................................................... 17
7.4.1 Indicator characterization ............................................................................................. 18
7.4.2 Sensitivity analysis and totals ....................................................................................... 20
7.4.3 Results summary and interpretation ............................................................................ 20
7.5 Cost benefit analysis and future projections ........................................................................ 21
7.6 Social Impacts ....................................................................................................................... 24
8 Composting Technology Comparison ........................................................................................... 24
8.1 Assumptions .......................................................................................................................... 24
8.2 Comparison ........................................................................................................................... 25
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9 Conclusions ................................................................................................................................... 26
9.1 Recommendations ................................................................................................................ 26
9.2 Technology recommendation ............................................................................................... 26
10 Bibliography .............................................................................................................................. 28
11 Appendices: ............................................................................................................................... 29
11.1 Smaller Survey ....................................................................................................................... 29
11.2 Smaller Survey Additional Comments Summary .................................................................. 29
11.3 Pickup location map .............................................................................................................. 31
11.4 Modelling code (Software: Engineering Equation Solver) .................................................... 32
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2 Highlights
1.5 tonnes of food waste diverted from landfill
Projected 45 tonnes of food waste per year could be diverted from landfill at JCU
JCU is in a strong position to expand this program
Personal engagement is most effective in achieving behavioural change
Combined worm farm, compost system with liquid sump is a highly effective food waste processing method
3 Abstract This project was implemented to quantify the amount of organic waste produced in staff lunch rooms and assess the impact of separating and treating this waste. The project also incorporated investigation of behavioural barriers to implementing organic waste recycling, analysis of the impact of treating commercial and college waste streams and comparison of treatment technologies.
Initially, staff from 11 different lunch rooms volunteered to manage compost bins, emptying to central locations weekly. Over the duration of the project, 4 more lunch rooms and 3 coffee shops came on board. This number continues to increase via word of mouth. On average, 0.1 kg/staff member/week and 20 kg/food outlet/week was collected. Throughout the project, 1.5 tonnes of food waste was diverted from landfill to compost. It was found that every tonne of organic waste diverted from landfill avoided the loss of 1.663 t CO2 (a 34 fold reduction), 13.6 kg nitrogen and 3.5 kg phosphorus. Over the project, this is equates to a 𝐶𝐶𝑂𝑂2 equivalent of driving around the entire coast of Australia and a fertilizer value of over $1000. It is expected that with full staff, college and food outlet uptake, these values would increase 10 fold. A sensitivity analysis showed that the majority of emissions resulted from organic decomposition, with a very small fraction resulting from transport.
Diverted organic waste was treated using a novel technique which combines composting, vermiculture (worm farming) and wicking moisture from a water sump. The treatment technique was found to be very effective for this application.
Two surveys (N=75 & N=183) indicated that 40 – 80% of respondents would like to see organic waste bins at various locations on campus and that >30% of respondents were willing to take an active role in their management. Project participants indicated that the feeling of being able to make a positive contribution towards reducing their environmental impact was their main motivator. Behavioural barriers identified were lack of knowledge/interest from other staff in lunchrooms and concerns of pests and bad odours.
Signage was developed to inform and encourage the use of compost bins. In future, signage should be placed on regular waste bins to intercept people disposing food waste in these. Odours and pests were not found not to be problematic. It was predicted that the impact of lunchroom organic waste recycling was relatively little in comparison to that which could be made from addressing commercial and college waste streams. The social impact of encouraging staff to be conscious of their food waste, however, is very significant. As such funding has been provided by facilities and operations to continue
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the project, with aims to implement a more sophisticated effective microbe digestion composting technique in the future.
4 Introduction: 4.1 Aims and Objectives
This project has four core aims:
1. Provide staff with the opportunity to manage food waste in their staff rooms 2. Educate staff on the impacts of sending food waste to landfill 3. Developing a report estimating campus wide organic waste production and impacts of
improved management 4. Collaborate with a research project which aims to identify hurdles in understanding of organic
waste and the impacts of education on environmental and public health.
The latest national food waste assessment indicates that lack of data and understanding are the key hurdles to managing food waste in Australia.1 This study aims to make a positive contribution to addressing these issues at JCU.
4.2 Project Overview
The project was divided into four categories:
1) Immediate change – Engage staff with a survey and enable willing staff to recycle their food waste by providing bins, weekly collection and information about what to compost and why. This bottom up phase is supported by staff and student volunteer efforts. Composting was already occurring at the Rotary College community garden and had stimulated significant interest. The garden is open to all JCU staff and students.
2) Business case - Quantify the mass of organic waste generated from staff lunch rooms and combine this with estimates from colleges and campus businesses. This data will be processed using life cycle analysis techniques, assessing a variety of technologies. Sensitivity analysis will also be used to identify what variables most affect recommendations so people can gauge how applicable these results might be to their own scenarios.
3) Behavioural change – Survey results and collaboration with JCU public health researchers will identify barriers to organic waste recycling. Results will inform a communication plan addressing social and environmental influences on people's organic waste recycling habits.
4) Reporting – All results will be reported to JCU management to prompt formal organic waste management procedures. All results will also be made publicly available and distributed to interested parties.
4.3 Background Information
It is estimated that 50% of food is wasted in the value/ distribution chain between the farm gate and the plate. This study focuses only on food waste, both avoidable and unavoidable, generated in a lunchroom setting. In Australia in 2004, this stream was estimated to have an equivalent cost to consumers alone of $5.2 billion, not accounting for wasted energy and resources. Food waste makes up 30 – 40 % of domestic waste volumes [1,2]. Recycling this waste at the source reduces transport
1 http://www.environment.gov.au/protection/national-waste-policy/publications/national-food-waste-assessment-final-report
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costs by this fraction, recycles nutrients and eliminates emissions associated with the uncontrolled fermentation of this waste in landfill.
Nutrient recycling is necessary to improve agricultural efficiency and reduce risk of eutrophication. Nitrogen and phosphorus are key nutrients required for all plant growth. Nitrogen harvesting from air costs 3% of the global energy budget and peak production of phosphate from fossil reserves is predicted to occur between 2030 and 2040 [3]. Additionally, recent estimates suggest that global nitrogen and phosphorus loads on the environment significantly exceed planetary boundaries and pose a high risk of a large scale ocean anoxic event and widespread eutrophication2 of localised freshwater systems [4]. While a significant portion of this load comes from inefficient fertilizer application, approximately 6% is estimated to be due to food waste [5].
Fermentation of food waste in landfill results in generation of methane, nitrous oxide and CO2, all of which are greenhouse gases. Methane and nitrous oxide are approximately 25 and 298 times higher global warming potential (GWP) than CO2, respectively. For every ton of food waste diverted from uncontrolled fermentation in landfill, saving of between 1.9 tonnes CO2 equivalent (CO2-e) is made [6].
5 Staff Engagement and Communication 5.1 Survey and meeting outcomes
Survey 1 (smaller survey, provided in Appendix section 11.1.3):
• September 2015 • Distributed on social media pages relevant to JCU and received • 75 responses (44 staff, 8 staff/student and 23 students) • Aimed to identify interest in this project
Survey 2 (larger survey, part of a research project performed in collaboration with this work4):
• September 2016 • Distributed via JCU email networks • Surveyed 183 JCU staff and students, 20% of whom were participants in this project • Aimed to identify factors relevant to food waste reduction at JCU
5.1.1 Composting interest and participation
The larger survey found that 72% of staff eat in staff lunchrooms and 69% of respondents dispose of food waste at least once on campus per day. Another study conducted at JCU5 found that young people waste more food than older people and that there is a significant relationship between eating
2 Eutrophication occurs when high nutrient loads cause rapid algal growth, resulting in waterway oxygen depletion and fish kills 3 In future, it is recommended that contact information be mandatory to ensure that contact can be made with all respondents who are interested in being involved. Where contact information was left, respondents were contacted to identify: room locations for bins; staff interest in transporting to garden for composting; staff interest in garden involvement; and estimate number of people using bins 4 Rike Wolf, College of Public Health, Medicine and Veterinary Services, JCU – [email protected] 5 Research in publication. Contact [email protected] for further information
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outside the home and quantity of food waste. These factors combined highlight students at JCU as a key demographic to address food waste reduction.
Figure 1 below indicates that both sample groups showed significant interest in having the option to compost their organic waste on campus. It also shows that over 30% of people were willing to commit effort towards emptying a bin, which suggests that an opportunity exists to empower people to take action.
Figure 1 – Interest in composting at JCU
Initial survey responses identified 23 staff in Townsville and 8 in Cairns who were interested in emptying an organic waste bin on a weekly basis for the 6 month duration of this project. When semester resumed, contact was made with these staff via three rounds of emails and directed phone calls. The number of staff participating in on-site composting changed for various reasons including: staff becoming unavailable due to field work; staff wanting to take compost home; new staff getting involved via word of mouth; interested staff using the same lunchroom; and a lack of response.
It was identified that most staff were not interested in attending/ dropping organic waste to the community garden and that central collection points would be ideal. This option also reduces associated transport costs. Over the course of the project, 11 staff lunchrooms dropped off organic waste to central locations on a regular basis, while two more took it home to their own compost.
Using a map of JCU, ideal central collection locations were identified (section 11.2) and arrangements were made to collect organic waste using a solar powered golf cart already available at JCU. Since this project is user driven, it was decided that requesting permission from building managers was not necessary although engagement may be necessary in future if more official arrangements are made. As of September 2016, Facilities and Operations has been funding a cleaning staff member to make bin collections.
5.1.2 Staff Comments and Concerns
The additional comments responses were significant and are summarized into categories in section 11.2. Points raised by many respondents and key points affecting the project are listed below:
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
Publiccompost bins
(N=75)
Publiccompost bins
(N=183)
Stafflunchroom
compost bins(N=75)
Stafflunchroom
compost bins(N=183)
Willing toempty publicbins (N=75)
Willing toempty stafflunchroombins (N=75)
Posit
ive
Resp
onse
s
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• Barriers: o Concerns of bad odours o Concerns of attracting pests o Concerns of misuse i.e. plastic contamination o Lack of understanding of the benefits o Lack of cold storage options (larger survey response)
• Recommendations o Integrate organic waste bin emptying by cleaning staff duties o Use detailed signage to educate people on correct use o Engage participating staff to ensure they know their efforts are appreciated
5.1.2.1 Odour and Pests
Concerns were addressed by holding face to face consultations with staff interested in participating. It was found that while many staff held concerns about odours and pests, they were happy to undergo a trial period where bins were emptied weekly, to identify the reality of these concerns. Neither of these concerns were found to be issues during the period and weekly emptying was continued for the remainder of the project. No further issues arose, accept in scenarios where staff did not empty the bins.
5.1.2.2 Lack of Understanding
Although the smaller survey identified lack of understanding as a barrier to uptake of composting practices, the larger survey showed that 79% of respondents rated their understanding of food waste impacts as good or higher. This suggests two things: 1) that the groups surveyed are biased towards people with an understanding or interest in food waste; and 2) that people perceive food waste issues as poorly understood by their peers. This highlights an opportunity to engage and empower enthusiastic people to be agents for social change in this area. Interestingly, research at JCU6 has suggested that people welcome the idea of being empowered people to do the right thing rather than being regulated.
5.1.2.3 Distributed composting sites
Various survey respondents suggested composting waste in gardens around campus, but this option was deemed inappropriate by the sustainability action group due to the necessity of management and risks of attracting pests.
5.2 Behavioural change
As identified, creating behavioural change is integral to the success of organic waste recycling. The larger food waste survey conducted at JCU found that the key factor to encourage organic waste recycling are:
1. Convenience i.e. having bins within reach 2. Signage and communication 3. Knowledge of making a positive difference 4. Receiving fresh produce grown with the compost in return
The following steps were taken to address these points:
6 Research in publication. Contact [email protected] for further information
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Table 1 – Steps taken to enact behavioural change
Key Factor Steps Taken Convenience • Bins placed in lunchrooms close to other bins Signage & communication
• Email sent by bin manager, explaining how to use it • Signage (section 5.2 below) placed above compost bins • NOTE: feedback indicated that personal interactions were the most
effective method of improving correct use of the organic waste bins Knowledge of making a positive difference
• This report will be distributed to staff to highlight the impact of their efforts
Receiving fresh produce from compost
• When excess produce was available from the community garden, some was distributed to staff lunchrooms contributing the most waste
• NOTE: This was informal and could be better formalised to ensure all staff receive some produce. An option also exists to give staff free compost and liquid fertilizer
Figure 2 below shows that waste masses recovered are variable but stable over the long term. The initial increase is partly due to increased staff numbers as the semester begins in February, and partly due to a learning period where people become familiar with separating organic waste.
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Figure 2 – Organic waste masses collected from various central collection points. Only total waste data was collected after June 2016.
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5.3 Signage
The larger JCU food waste survey found that signage alone is likely to prompt people to waste less food. Results suggested that signage should focus on environmental impacts, food security and resource consumption, in that order.
In this project, signage was developed to address the aim of educating staff on the impacts of sending food waste to landfill and in response to recommendations made by survey respondents. Signs were made to be placed in lunchrooms close to organic waste bins. A4 size paper was used to enable easy printing and laminating of extra signs. BH Graphics was contracted to design posters to with the goal of encouraging people to use bins by educating them and using positive messages. Two posters (shown below) were created – one ‘how to’ poster, educating people what can and can’t be composted and a ‘why’ poster, outlining the environmental benefits of composting organic waste.
Figure 3 – Organic waste bin sign 1 – “How to compost”
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Figure 4 – Organic waste bin sign 2 – “Why compost”
5.4 Feedback survey responses
Nearing the completion of the pilot study, participants were contacted to provide feedback on the project. Twenty-two responses were received and the majority of feedback was positive. The questions posed and a summary of key points is given below.
1. What were the best aspects of participating in this pilot study? a. Empowering people to take responsibility for their waste and make a positive
difference for the environment b. Staff uptake was very fast and positive c. Useful to talk to colleagues about a non-work related interest
2. What parts of this project can be most improved? a. Needs to be made available in all lunch rooms and around the university b. Engagement:
i. Improved student engagement on Rotary College where composting occurs ii. Explain to staff what goes in the bin
c. Bins: i. Larger bins for large kitchens
ii. Pedal bin to avoid touching lid d. Collections:
i. Pickup time not suitable to some ii. Shared responsibility for placing bin in pickup location will reduce possibility
of missed emptying due to sickness/ meetings/ holidays etc. iii. Incorporate into cleaners contracts iv. Option for more frequent emptying - fast filling early in the week has
occasionally attracted flies v. Collection point signage will help multiple staff to share emptying duties
e. Signage:
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i. More detailed signage on what can go in the compost. ii. Signage on the general waste bin
3. Was the signage provided helpful/not helpful? Why? a. All responses suggested signage was helpful b. Improvements:
i. People don’t read it – make simpler ii. Update to include what contribution they’ve made
iii. More info on where to place bins for emptying iv. Reminder above other bins to use organic bin
4. Did the majority of staff in your area use the bin? a. Yes – 77% b. Approximately half – 9% c. Unsure – 14%
5. Do you wish to continue – 100% of respondents answered yes 6. How likely would you be to recommend the program to others at JCU?
a. Very likely – 86% b. Likely – 14%
7. Additional comments: a. Taking compost home is great b. More support from JCU would be helpful to improve the coverage of this program
6 Logistics 6.1 Organic waste bins and biodegradable liners
Organic waste bins were obtained from a supplier already used by JCU7. The volume of the bin was selected by end users but in general, 23L bins were used by staff lunchrooms servicing more than 25 people and 7L bins for less. This allocation was found to be effective, with 23L bins in lunchrooms servicing 25 people becoming filled in one week.
Biodegradable bin liners were trialled and found effective at reducing bin cleaning frequency. The permeable nature of the liners meant that bins required rinsing if high moisture content food waste was disposed of, but mould stains often found in compost bins were not an issue. The liners were also found to be strong enough to hold the contents of a full bin and able to degrade relatively quickly in the compost pile. Mould in smaller 7L bins were also effectively managed by lining them with a newspaper.
6.2 Composting method
Figure 5, Figure 6 and Figure 7 below show the composting method used in this study. The system, designed by a local permaculture contractor8, is a combination compost and worm farm with a liquid sump below to collect nutrient rich leachate and ensure moisture in the system is maintained. Compost rests on a tight trampoline cover enabling the centre to rest in liquid and creating a storage volume around the sides which can be easily drained. The drain pipe is made of flexible agricultural pipe, hooked upwards, which can be lowered for collection of leachate used as liquid fertilizer on the nearby community garden. The sides of the compost bay are hinged to allow for easy collection of fully composted material. A tarp is held in place by hooks to ensure that rain does not wash nutrients into nearby waterways.
7 https://www.sourceseparationsystems.com.au/ 8 Brett Pritchard – http://www.biowicked.com/
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The compost bay was started with a mixture of leaves, horse manure and a mixture of effective microbes to eliminate potential of methane formation. Organic waste is added to the bay in 0.5 × 1 meter areas and covered with leaf matter collected by groundsmen from around campus to maintain a suitable carbon content (food waste often has lower C:N ratio than what is necessary for ideal composting). Each new layer is watered with EM inoculate diluted 10:1 with water to increase moisture and accelerate the composting process. The inoculant is collected from either the drain pipe of the compost area or a food waste digester at University Hall. This layering is continued until the small pile reaches 1 m in height before moving to the adjacent 0.5 × 1 meter block. This rotating procedure ensures that worms in the system are able to stay away from fresh organic matter which often contains citrus and other acidic fruits which may harm them. The composting system was found to be highly effective. Figure 7 shows the decomposing organic matter in the bottom of a compost pile.
Figure 5 – Combined wicking worm farm and compost station used to treat organic waste. Dimensions are approximate.
Pallet walls
Compost
Black plastic rain cover
TOP VIEW
SIDE VIEW
Water level
Trampoline cover stapled taut
Drain pipe
Base frame with black plastic lining
1m
4m
0.2m
1m
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Figure 6 – Wicking worm farm composting bay with walls up
Figure 7 – Wicking worm farm composting bay with walls down
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7 Life Cycle Analysis 7.1 Goal and scope
This analysis aims to quantify the true impact of separating and recycling organic waste at JCU. The scope of the analysis is limited to the staff organic waste recycling project although data will be used to project the impacts of full uptake of organics recycling in lunchrooms and by commercial businesses on campus. This work also lays a framework for future analysis.
Life cycle analysis is presented in line with ISO14040:2006. Because this system is very simple, many steps of this analysis are presented together, within the diagrams and sections below. These include the system boundary, inventory of impacts, allocation of the portion of an impact to the functional unit (e.g. transport), impact categories and indicators.
7.2 Functional unit and system boundary
The functional unit being considered here is a group of 11 staff lunch rooms at a university containing organic waste recycling bins. This selection has been made because it represents the whole of the dataset collected and because truck pickup includes all waste and cannot be applied to a single lunchroom alone. The system boundary for food begins at the office disposal sites and finishes at the final point of disposal (either the refuse site or JCU on-site composting). This analysis was made on a per week basis using an organic waste mass averaged over 13 weeks from 22/01/2016 – 15/4/2016.
7.3 System characterisation and assumptions
Assumptions and limitations are discussed in the relevant sections of this assessment, but for ease of reference are summarized here:
7.3.1 Food waste
• Organic waste stream is fixed and cannot be reduced. Food waste is all assumed to be unavoidable food waste since there is no way of quantifying here what portion is avoidable.
• Production costs of the food waste remain the same, irrespective of whether it is composted or wasted.
• Average total nitrogen in raw food waste is 1.36±0.82 % (by mass) [7–9] • Average total phosphorus in raw food waste is 0.35±0.06 % (by mass) [7,9]
7.3.2 Transport
• Costs associated with the bins are not considered in this analysis since their manufacture is carbon neutral.
• The costs associated with the use of solar powered electric buggies is negligible because the fraction of their use associated with this project is very small.
• A garbage truck will be filled to capacity before depositing at landfill. As such, the carbon cost associated with the entire trip is accounted for and organic waste is allocated as a volume fraction.
• The total distance travelled by a garbage truck consists of the 6 km loop around JCU, a 27 km return trip to the Stuart landfill and an additional 62.5±12.5 km for other pickups (estimated using google maps and by Townsville Waste Services, respectively).
• Truck fuel economy is 1.45±0.15 km/L, estimated by Townsville Waste Services.
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• Density of organic waste is 1.029 kg/L.9 • Garbage truck total fill volume is 28 m3 and it is emptied when filled to 27±1 m3 • Total fuel related emissions are accurately estimated by National Greenhouse Accounts
Factors 2013 document • The impact of their uncertainty will be investigated later in this document.
7.3.3 Landfill
• Landfill is covered/capped with soil before decomposition begins • Total methane produced in landfill is accurately estimated by National Greenhouse Accounts
Factors 2013 document. The impact of their uncertainty will be investigated later in this document.
• Total waste mass in landfill is 7.5% construction waste (advised by Townsville Waste Services) with the remainder an equal split of municipal and commercial waste. This affects the expected total methane and fraction of flared methane estimates.
• Density of waste at landfill, when waste volume is measured, is equal to maximum compaction achieved by truck (10t/28m3).
• Current methane emissions from site result from waste deposited in the last 5 years. • No nutrients are lost to the environment from the landfill
9http://www.epa.vic.gov.au/business-and-industry/lower-your-impact/~/media/Files/bus/EREP/docs/wastematerials-densities-data.pdf
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7.4 Life Cycle Impact Assessment
DISPOSAL OPTION
AIR
- Global
WATER
- Eutrophication
LAND
- Land use
Transport CO2
Landfill area
Compost area
Nutrient site runoff (captured
and reused)
Compost Methane (CO2-e)
Landfill methane (CO2-e)
SYSTEM BOUNDARY
INDICATORS
Nutrient loss (water and land contamination)
Landfill Composting
Food Waste (11 staff lunchrooms)
IMPACT CATEGORIES
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7.4.1 Indicator characterization 7.4.1.1 CO2 from landfill
The Australian Department of Environment National Greenhouse Accounts Factors 2015 (NGAF) document was used to calculate food waste emissions from landfill as a scope 3 emission i.e. emissions generated outside an organization’s boundary. Only methane emissions are considered in this calculation since CO2 emitted from the biomass was relegated from the atmosphere to create that biomass. Emissions were calculated using factors given in Appendix 4 of the NGAF document.
𝐺𝐺𝐺𝐺𝐺𝐺 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 [𝑡𝑡 𝐶𝐶𝑂𝑂2 − 𝑒𝑒] = 𝑄𝑄𝑗𝑗𝐸𝐸𝐹𝐹𝑗𝑗
𝐺𝐺𝐺𝐺𝐺𝐺 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 [𝑡𝑡 𝐶𝐶𝑂𝑂2 − 𝑒𝑒]= �(𝑄𝑄 × 𝐷𝐷𝑂𝑂𝐶𝐶 × 𝐷𝐷𝑂𝑂𝐶𝐶𝐹𝐹 × 𝐹𝐹1 × 1.366) − 𝑅𝑅�× (1 − 𝑂𝑂𝑂𝑂) × 25
(1)
Where 𝑄𝑄 [t] is the quantity of food waste; 𝐷𝐷𝑂𝑂𝐶𝐶 is the degradable organic carbon fraction (0.15 for food waste); 𝐷𝐷𝑂𝑂𝐶𝐶𝐹𝐹 is the degradable organic carbon content which is dissimilated (0.84 for food waste); 𝐹𝐹1 is the methane fraction of landfill gas (0.4374 at Stuart landfill); the factor of 1.366 represents the conversion rate of carbon to methane; 𝑅𝑅 is the recovered methane during the year (zero); 𝑂𝑂𝑂𝑂 is the oxidation factor, which is assumed as 0.1 since Stuart landfill is covered and well managed; and the factor of 25 represents the CO2 equivalent global warming potential of methane.
Methane flaring is practiced at Stuart landfill and is accounted for by multiplying the total expected CO2 emission (equation (1)) by the fraction not flared. The fraction of methane likely to be flared [t methane flared/ t methane generated] is estimated by combining flaring rate with (averaged over a 9 month period) with the expected volume of methane generated based on total landfill deposit rate (averaged over 4.75 years)10. The expected methane volume was calculated using the NGAF 2015 document, assuming 7.5% construction municipal solid waste, with the remainder evenly distributed between commercial/industrial and municipal waste.11
7.4.1.2 CO2 from transport
Transport related CO2 emissions were calculated based on methods provided in section 2.1.3 of the NGAF 2015 document.
𝐸𝐸𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 [𝑡𝑡 𝐶𝐶𝑂𝑂2 − 𝑒𝑒] =𝑄𝑄𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 × 𝐸𝐸𝐶𝐶 ∑ 𝐸𝐸𝐹𝐹𝑗𝑗𝑗𝑗
1000
(2)
Where 𝐸𝐸𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 is the CO2 equivalent emission for combustion of fuel related to transport; 𝑄𝑄𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 is the volume rate of fuel (kilolitres); 𝐸𝐸𝐶𝐶 is the energy content factor for the fuel type (for diesel, 38.6 gigajoules/kilolitre); and 𝐸𝐸𝐹𝐹𝑗𝑗 is the emission factor related to emission type 𝑗𝑗, which includes the effect of an oxidation factor (for diesel, 69.9, 0.1 and 0.2 kilograms CO2-e per gigajoule for CO2, CH4 and N2O,
10 All landfill related data was provided by Townsville Waste Services 11 Alternatively, the amount flared could be calculated using a rate of methane flared per ton deposited to landfill although this does not account for differences in waste type or the timespan over which emissions occur (decades).
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respectively). The allocation of the fraction of fuel used to transport the organic waste was also accounted for, taking into account the volume of food waste, the total capacity of the truck and the distance travelled by the truck in a whole run to the landfill. The values used to make these calculations can be found in section 7.3 and calculations in the appendix (section 11.4).
7.4.1.3 Composting CO2
Composting related emissions were estimated using equation (2)(3) and (4), from section 5.2 of the NGAF 2015 document:
𝐶𝐶𝐺𝐺4 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 [𝑡𝑡 𝐶𝐶𝑂𝑂2 − 𝑒𝑒] = 0.019𝑄𝑄 (3)
𝑁𝑁2𝑂𝑂 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 [𝑡𝑡 𝐶𝐶𝑂𝑂2 − 𝑒𝑒] = 0.03𝑄𝑄 (4)
Where 𝑄𝑄 is the mass of wet organic waste in tonnes.
7.4.1.4 Nutrient CO2 used for fertilizer production
The CO2 equivalent for nitrogen and phosphorus fertilizers was assumed to be 6.2 tonnes CO2-e/ tonne N and 1.66 tonnes CO2-e/ tonne P.
7.4.1.5 Nutrients lost in landfill
Stuart landfill does not practice any nutrient removal or recovery practices so it is assumed that all nutrients in landfill are lost to the environment in a non-useful form. It is also assumed that negligible nutrients are lost via the composting process, making the difference in nutrient loss/recovery between the two techniques the total nutrient content of the food waste (given in section 7.3.1)
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7.4.2 Sensitivity analysis and totals
Table 2 below summarises the uncertainty in each key variable contributing to the life cycle analysis, on a weekly basis and as a total over the course of this project until 02/09/2016. The total amount continues to increase as all participants elected to continue past this scheduled finish date.
Note that the weekly amount does not scale to the total amount as the total amount also includes earlier times in the project when fewer staff were using bins.
Table 2 – Sensitivity analysis of emissions and food waste nutrient content
Variable Weekly ± Total Relative uncertainty (%)
Major uncertainty contributors
CO2 from landfill [t]
0.042 0.005 2.523 13% waste mass (52%), DOC (16%), DOC_F (16%), F1 (16%)
CO2 from landfill transport [t]
0.0002 0.00003 0.010 21% extra travel distance (38%), fuel economy (24%), waste mass (18%), calculations (20%)
CO2 from compost [t]
0.001 0.0001 0.075 10% waste mass (86%), N2O factor (10%), CH4 factor (4%)
CO2 used to produce fertilizer [t]
0.002 0.001 0.137 57% nutrient density (97%), waste mass (3%)
CO2 total offset [t]
0.043 0.005 1.299 13% waste mass (51%), DOC (14%), DOC_F (14%), F1 (14%), nutrient density (5%)
Nitrogen in food waste [g]
343 237 20713 69% nutrient density (98%), waste mass (2%)
Phosphorus in food waste [g]
88 33 5331 38% waste mass (78%), nutrient density (22%)
7.4.3 Results summary and interpretation
Total emissions offset by the project (as of 02/09/2016) was 2.523 tonnes CO2-e and weekly emissions offset from 11 lunch rooms was 0.0407 tonnes CO2-e. In comparison, the emissions produced by composting were 34 times less than if the waste had been sent to landfill. Landfill emissions contribute 99.5% while transport emissions contribute the remaining 0.5%, meaning that they can effectively be ignored. Although flaring is conducted at the Stuart landfill, its contribution to emissions reductions was calculated to be negligible.
Landfill emissions have an uncertainty of 13%, half of which comes from waste mass uncertainty and the remainder from calculation methods (assuming 5% uncertainty in all conversion factors). Notably though, as the mass increases, the relative uncertainty in the mass decreases and the total uncertainty
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becomes increasingly dependent on the factors used in equation (1), to the point where they are the primary sources of uncertainty. Unless a more detailed technique is used to estimate landfill related emissions, this uncertainty must be accepted.
On this basis, the emissions from food waste can be estimated using only the method described by equation (1). Using this method, the conversion factor for organic waste to CO2 equivalent is estimated to be 1.663±0.144 [t CO2-e/t food waste]. This is lower than the general conversion factor given in the NGAF document because the landfill is capped and contains a lower methane percentage. Most significant improvements in emission estimate accuracy can be achieved by increasing accuracy of emission calculations with decomposition in landfill.
Total nitrogen and phosphorus loss were estimated to be 20713 g and 5331 g, respectively. Nutrient loss uncertainties were 69% and 38% for nitrogen and phosphorus, respectively, and primarily came from uncertainty in food waste nutrient density – a common issue with nutrient estimates. Nutrient loss estimates are highly variable due to the uncertainty in nutrient content and relatively few data sources available. It is unlikely that this uncertainty can be reduced, since nutrient densities vary significantly between from week to week as food waste content varies. The estimates made here may be improved by more thorough literature search and by measurement.
7.5 Cost benefit analysis and future projections
This section presents the estimated monetary, emissions and nutrient costs of implementing various scales of organic waste recycling at JCU Townsville. Results are presented on an annual basis in Table 4. Table 3 below shows estimates of organic waste masses from various streams. Staff lunch room estimates are based on data collected in this study. College estimates were provided by the JCU environment officer Adam Connell and are based on data from the BioRegen digester at University Hall. Commercial business estimates are based on a 13-week sampling period conducted at the end of semester 1 and beginning of semester 2 to ensure students were on campus.
Calculation assumptions:
• Labour cost to do composting = $28.82/hr (JCU pay grade HEWL01-10) • Labour cost increases by approximately 0.5hr for every 100kg collected. Note that higher
masses would require a larger collection vehicle. • Skips at buildings 15, 17, 57, 18, 39 and 8 (6 skips) receive food waste from this project • Transport cost is the product of the skip emptying cost ($34.22/skip); the number of skips
emptied (6) and the fraction of food waste in a skip based on collection data (3.1%) • Carbon cost = $12.25/ton (based on the Australian government Clean Energy Regulator
November 2015 auction) 12 • Organic fertilizer cost = $0.033/g N13 • Nutrient cost and CO2 contribution assume that nutrients not recycled must be purchased for
the garden • Total waste produced is scaled based on 5 days per week, 48 weeks per working year
12 http://www.cleanenergyregulator.gov.au/ERF/Auctions-results/November-2015 13 http://www.bunnings.com.au/hortico-10kg-organic-garden-fertiliser_p2960033
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Table 3 – Estimated food waste masses for various sources
Source Waste Mass [kg/wk] Waste Mass [t/yr] All staff lunch rooms (1477 full time equivalent staff)
143 6.87
Colleges 729 35 Food outlets 62 2.98 Total 973 45.09
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Table 4 – Cost benefit analysis comparison of landfill and organic waste composting
Item Landfill Organics Recycling This project
(260 staff in 11 lunch rooms)
All Staff (1477 full-time equivalent)
Colleges (3000 students)
Businesses (five cafés)
Total This project (260 staff in 11 lunch rooms)
All Staff (1477 full-time equivalent)
Colleges (3000 students)
Businesses (five cafés)
Total
Organic waste mass [t]
1.21 6.87 35 2.98 45.09 1.21 6.87 35 2.98 46.3
Cost [$/y] Labour cost [$] - -- - - - 201 909 4,425 2,413 7948 Transport cost [$]*
22 127 647 60 856 - - - - -
CO2 cost [$] 27 140 713 66 946 1 4 21 2 28 Fertilizer value [$]
0 0 0 0 0 546 3,100 15,792 1,453 20,891
CO2-e emissions [t CO2-e/y] Biological CO2-e emissions [t]
2.00 11.38 57.98 5.52 76.88 0.06 0.34 1.72 0.16 2.28
Transport emissions
0.01 0.04 0.22 0.02 0.29 - - - -
Nutrient production emissions
0.11 0.62 3.16 0.29 4.18 - - - -
Nutrient loss [kg/y] Nitrogen 16 93 476 44 629 - - - - - Phosphorus 4 24 123 11 162 - - - - -
* Note that while the amount of waste collected may be reduced, the number of collections may not vary, since staff lunchroom food waste does not contribute significantly to the bin volume and bins must remain in place for each building.
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7.6 Social Impacts
Several factors which cannot be accounted for using metrics must also be considered when assessing the value of this project. All of these factors have been reinforced by feedback received from staff participating in this project:
• Empowerment of staff who want to recycle their organic waste • Cultural change affected by enabling staff to separate organic waste • Increased visibility of JCUs role as leader in sustainability • Increased staff and student understanding of the impacts of organic waste
8 Composting Technology Comparison 8.1 Assumptions
Various levels of complexity exist for food waste recycling, below three main options are examined:
METHOD OPERATING CONDITION ASSUMPTIONS
COMPOSTING • Thermophilic (hot composting) OR
• Aided by effective microbes • Completion in 3 months • 45˚ slump angle • Compost bulk density = 600kg/m314,15 • Compost area is calculated assuming half is used for pile access
and management
EM DIGESTION • dilution ratio of 1 part food to 2 parts water in a series of tanks over 30 days
DEHYDRATION • performed in a 200L vessel at 100˚C to ensure complete pasteurisation
A technology not considered here is anaerobic digestion for biogas production, which may become available in the future if implemented at a nearby wastewater treatment plant. Food waste falls into the category of medium to high potential for environmental impact based on guidelines for open windrow composting from the Department of Environment and Heritage Protection16. Notably though, this does not account for the use of effective microbe inoculation used in this study, which is expected to reduce this risk by reducing the period of biological instability where risk of odour formation and pest attraction are high.
14 http://www.transformcompostsystems.com/articles/Basics%20of%20Composting%20June%202009.pdf 15 http://open-furrow.soil.ncsu.edu/Documents/DHC/Composting_Basics1.pdf 16 https://www.ehp.qld.gov.au/licences-permits/business-industry/guidelines.html
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8.2 Comparison Table 5 – Comparison of different organic waste treatment technologies
COMPOST EM DIGESTION17 DEHYDRATION
Treatment capacity [kg/day]
- Expandable without significant capital
investment
400 (2x200kg batches in continuous operation)
Residence time [days] 90 – 180 30 1
Area requirement [m2] 405 ~30 6.2
Power requirement (kW) 0 ? 32.3
Annual power cost [$] 0 ? $ 34,821.63
CAPEX [$] 0 $ 10,230.00 $ 103,000.00+GST
Labour cost (annual) [$] $11,500.00 (labour) $ 15,578.00 (labour and inoculate)
$ 11,500.00 (labour)
Emissions [tonnes CO2-e/ tonne food waste]
0.022 0 0.186
Product Compost/ solid organic fertilizer
Liquid organic fertilizer Dry compost/ solid organic fertilizer
Product use Significantly improves microbial activity; slow
release nutrients
Fast release nutrients; instant boost to
microbial activity by addition of EM
Addition to compost or direct application as pelletized fertilizer; burned for heating
Volume change 0 + 200 % (water addition)
- 85 %
17 Data assumed based on JCU Food Waste Recycling Proposal 2011 by Swinburne University. This system was designed to treat up to 500 kg/week. Updated quotes can be obtained by contacting the supplier via [email protected]
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9 Conclusions The project successfully provided staff with the opportunity to manage food waste in their staff rooms, although a larger advertising campaign will likely attract more participants. Signage was developed to positively engage staff and educate them on the impacts of food waste. Feedback indicated that often staff did not take the time to read signage, but when they did, they found it useful. It was identified that often staff were not aware of the impacts of food waste and that they held unnecessary concerns of compost bins smelling bad and attracting pests. Further work must be done to address these gaps in knowledge and understanding. Staff who managed bins all reported a feeling of satisfaction and empowerment from being given an easy opportunity to make a positive environmental contribution.
An average of 25 kg/week was diverted from 11 staff lunchrooms and 80 kg/week from four businesses. It is projected that full staff uptake would result in diversion of 147 kg/week of food waste. Current participating businesses contribute a total of 62 kg/week. Colleges are estimated to produce 730 kg/week – this stream was not addressed in this project but one college already conducts EM digestion. During the project, a total of 1.523 tonnes of food waste was diverted, equivalent to 2.523 tonnes CO2-eq, or driving around the perimeter of Australia. The fertilizer value recovered was over $1000.
This project was awarded the TropEco Sustainability Award for Facilities and Operations, and contributed to Max Burns winning the Queensland Young Achiever of the Year Award for Sustainability. Additionally, contact was made by the Ecoprocess Technology Research Group at University Sains Malaysia and Cultivating Community18 (a Melbourne NGO) to discuss future collaboration opportunities. These results show that this project has significantly contributed to increasing the visibility of JCUs role as a leader in sustainability.
9.1 Recommendations
1) Behavioural change a) Run an advertising campaign to inform all JCU staff of this opportunity b) Encourage and empower enthusiastic staff to engage with their peers c) Do a face to face ‘composting induction’ for new areas taking on the project to ensure staff
understand the why and how of the project and to field any questions d) Establish formalised free fertilizer and free excess community garden produce program for
staff participating in the composting project 2) Logistics
a) Expand composting facilities to accommodate higher waste volumes b) Add signage to general waste bins (in the vicinity of a compost bin) directing people to divert
food waste c) Encourage businesses on campus to take part. Work with them to identify any barriers. d) Sell the fertilizer product at a rate in line with organic fertilizer
9.2 Technology recommendation
The composting method was found to be highly successful although manually transporting the solid product is labour intensive. If larger quantities of compost are produced in future, plans must be put in place to ensure proper usage on campus. Although some data was unavailable for EM digestion, this is likely be the best option for larger waste volumes as the process is more space and time efficient and the fertilizer product is primarily liquid, allowing for easy sale and use on campus. Dehydration is
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highly space efficient but capital and energy intensive and not recommended for JCU since land area is available for either compost or EM digestion.
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10 Bibliography [1] Commonwealth Department of Environment, National Waste Reporting 2013, (2013).
[2] Institute for Sustainable Futures, National Food Waste Assessment, 2011.
[3] K.L. Nelson, A. Murray, Sanitation for Unserved Populations: Technologies, Implementation Challenges, and Opportunities, Annu. Rev. Environ. Resour. 33 (2008) 119–151. doi:10.1146/annurev.environ.33.022007.145142.
[4] W. Steffen, K. Richardson, J. Rockstrom, S.E. Cornell, I. Fetzer, E.M. Bennett, et al., Planetary boundaries: Guiding human development on a changing planet, Science (80-. ). 347 (2015) 1259855–. doi:10.1126/science.1259855.
[5] D. Cordell, J.-O. Drangert, S. White, The story of phosphorus: Global food security and food for thought, Glob. Environ. Chang. 19 (2009) 292–305. doi:10.1016/j.gloenvcha.2008.10.009.
[6] Department of Environment, National Greenhouse Accounts Factors, 2015. www.environment.gov.au.
[7] M. Kim, M.M.I. Chowdhury, G. Nakhla, M. Keleman, Characterization of typical household food wastes from disposers: Fractionation of constituents and implications for resource recovery at wastewater treatment, Bioresour. Technol. 183 (2015) 61–69. doi:10.1016/j.biortech.2015.02.034.
[8] E. Tampio, T. Salo, J. Rintala, Agronomic characteristics of five different urban waste digestates, J. Environ. Manage. 169 (2016) 293–302. doi:10.1016/j.jenvman.2016.01.001.
[9] M. Wilewska-Bien, L. Granhag, K. Andersson, The nutrient load from food waste generated onboard ships in the Baltic Sea, Mar. Pollut. Bull. (2016). doi:10.1016/j.marpolbul.2016.03.002.
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11 Appendices: 11.1 Smaller Survey
REALLY FAST:
• Organic waste in bins = transport $ & GHG emissions • Organic waste in compost = free organic fertilizer = free food • Proactive staff and students are the beginning of the solution! • Be the change you want to see!
REGULAR SPEED:
This quick (1min) survey aims to gauging interest in organic waste disposal facilities at JCU.
Currently JCU has no facilities for student or staff organic waste disposal. This waste goes to landfill, costing money and decomposing to generate greenhouse gases. The problem can be addressed in the short term (now) by proactive staff and students and in the medium term (1yr) by the university. Showing interest now will help prompt change in our organisation. Are you interested in being part of the solution?
One proposed solution is to have staff and student managed organic waste bins in lunch rooms around the campus. Individuals or groups would take responsibility for their own waste (imagine that!), by emptying the bins, which will use compostable bin liners, into a compost system at the edible food garden at Rotary Hall. All are welcome to bare the fruits of the garden.
It's up to people as individuals to take responsibility for their actions and show everyone else how easy it is. You do have time to do this - take 30min to do something good for the environment and for your mental and physical health. Also, you close the loop on nutrients and get some food!
SURVEY QUESTIONS:
1. Are you staff/ student 2. Where would you like an organic waste bin – staff lunch room/ student area, Cairns/
Townsville 3. Would you be willing to empty the bin – Y/N 4. Contact information 5. Additional comments
11.2 Smaller Survey Additional Comments Summary
• Desirable organic waste bin locations o Near eating areas o Built into gardens around campus
• Equipment suggestions: o Visually appealing bins o Personal bins to put on desk and take home o Clearly marked to avoid misuse, include what not to put in bins and why (x6) o Central bins for buildings/building groups to be emptied by contractor (x5) o Multiple composting sites in gardens o Decentralized automated units
• Management suggestions: o Start the project ASAP and allow it to evolve – (x2)
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o Avoid bad odour (x6) o Weekly checks to ensure cleanliness (x4)
Bins are removed if not managed o No bins in public due to contamination risk o Bin emptying by cleaning staff (x3) o Long term volunteering unrealistic o Inter-college competition (judged by cleaners i.e. reduced waste) o Updates/feedback to people using bins o Contact details of project manager and individual bin manager o Suggest people to keep in freezer for as long as possible if possible
• Incentives: o Small donation into research accounts for participating staff o Make clear the benefit and necessity o Give fruit and veg from the garden back to participants
• Promotion: o General promotion/signage – x4 o Floating banner on website o Promote existing services i.e. BioRegen (can this be used if it is promoted?) o Make sure people don’t perceive their efforts as wasted o Show people process and outcomes e.g. tours of the garden– x2 o Workshops – composting, juicer pulp crackers/loaves/smoothies
Provide good blenders and dehydrators on campus o Videos o News articles o Competitions – best photo/video/eco food o Sell compost o Sell fruit from garden in refect
• Existing barriers o Staff numbers too low o Smell – x4 o Attract pests – x6 o Misuse – x4 o Perception of poor post processing – x2
recycle bins at refectory get emptied with other bins cleaners put recycle bins in with other rubbish
o People’s time o Understanding of benefits – x5
• Other comments o Battery recycling? o Creative arts materials drop off? o Upcycling workshops
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11.3 Pickup location map
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11.4 Modelling code (Software: Engineering Equation Solver) "JCU Bins Project CO2 Emissions and Sensitivity Analysis" {Notes: - units are included for parameters and calculated for variables to ensure dimensions match } "-------------------- INPUT VARIABLES --------------------" m_waste_organic = 1.523 {0.0252 * F_staff * Time_weeks} "(+/-0.0023) mass per week averaged over 13 weeks" {m_waste_organic = 0.6779} "(+/-0.0085) total mass composted as of 15/4/2016 - this includes holiday periods and pre project estimations. 0.8 used for eco-fiesta presentation analysis to account for extra waste collected" Time_weeks = 49 "-------------------- BUSINESS CASE --------------------" Cost_carbon_compost = 12.25*Emissions_compost "[$/tonne] - from the Clean Energy Regulator November 2015 auction" Cost_carbon_landfill = 12.25*Emission_organics Cost_fertilizer_N = 11.28/(10*1000*0.034)*N_loss_g "[$/gram] organic fertilizer using nitrogen as N:P ratio is higher here (http://www.bunnings.com.au/hortico-10kg-organic-garden-fertiliser_p2960033)" Cost_fertilizer_P = 11.28/(10*1000*0.015)*P_loss_g Cost_transport = Organics_fraction/JCU_fraction*trip_number*N_skip*Cost_skip "assume waste goes into 6 bins and it costs $10/bin to empty" Cost_wages = 50+(m_waste_organic-0.)*1000*12.5/100 "[$/wk] for 2hrs work at $25/hr" Value = Cost_carbon_landfill + Cost_fertilizer_N + Cost_transport - Cost_wages - Cost_carbon_compost N_staff_trial = 260 N_staff_tot = 1477 "Tsv: 1477 full time equivalent; 3554 staff total. Not including postgrad students" F_staff = N_staff_tot/N_staff_trial Cost_skip = 34.22 N_skip = 6 "Assuming skips at building 15, 17, 57, 18, 39 and 8" "-------------------- NUTRIENT LOSS --------------------" N_fraction = 0.0136 "(+/-0.0082) percentage of nitrogen as N in general food waste" N_loss_g = m_waste_organic*1E6*N_fraction P_fraction = 0.0035 "(+/-0.0006) percentage of nitrogen as N in general food waste" P_loss_g = m_waste_organic*1E6*P_fraction Ratio_N_P = N_loss_g/P_loss_g "-------------------- NUTRIENT CO2 OFFSET --------------------" Emission_nutrient_offset = 6.2*N_loss_g/1E6 + 1.66*P_loss_g/1E6 "-------------------- COMPOST EMISSIONS --------------------" F_compost_N2O = 0.03 F_compost_CH4 = 0.019 Emissions_compost = (F_compost_N2O+F_compost_CH4)*m_waste_organic "-------------------- TRANSPORT CO2 --------------------" "Garbage truck haulage CO2-equivalent" trip_number = Time_weeks "assume one pickup per week, the total mass was estimated over 34 weeks. 40 used for eco fiesta" economy = 1.45 [km/L] "(+/-0.15) FUEL ECONOMY. Estimated by townsville waste services." D_JCU = 13.5*2 + 6 [km] " DISTANCE (return trip + JCU loop distance). Estimated from google maps" D_other = 62.5 [km] "(+/-12.5) DISTANCE - extra distance before truck is full. Estimated by townsville waste services."
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D_tot = D_JCU + D_other "[km] DISTANCE total distance travelled before truck is full" JCU_fraction = 0.4 "+/-0.1 - The fraction of a truck filled by emptying industrial bins at JCU. Estimated by townsville waste services." V_waste_organic = m_waste_organic*1000/density_waste_organic "[L]=[t]*[1000kg/t]/[kg/L] VOLUME of organic waste" density_waste_organic = 1.029 "[kg/L] - assumed value based on victorian epa document http://www.epa.vic.gov.au/business-and-industry/lower-your-impact/~/media/Files/bus/EREP/docs/wastematerials-densities-data.pdf" V_waste_truck = 27000 "[L] volume of waste carried by a garbage truck" Organics_fraction = V_waste_organic/trip_number/V_waste_truck "fraction of organic waste per truckload" V_fuel_tot = D_tot/economy "[L] - total fuel used in one trip by a truck" V_fuel_jcu = V_fuel_tot*JCU_fraction "fuel volume [L] associated with one round of JCU pickups" V_fuel_org = V_fuel_tot*Organics_fraction "emissions calculation using national greenhouse accounts factors 2013:" EC_deisel = 38.6 "[GJ/kL]" EF_CO2 = 69.9 "emission factor CO2" EF_CH4 = 0.1 "emission factor CH4" EF_N2O = 0.2 "emission factor N2O" Emission_transport_jcu = trip_number*V_fuel_jcu/1000*EC_deisel*(EF_CO2+EF_CH4+EF_N2O)/1000 "tons - from CERS document" Emission_transport_org = trip_number*V_fuel_org/1000*EC_deisel*(EF_CO2+EF_CH4+EF_N2O)/1000 "tons - from CERS document" "-------------------- LANDFILL CO2 --------------------" "Landfill methane emissions CO2-equivalent" conversion_1 = 0.9067 "based on national food waste report" conversion_2 = 1.59 "based on national greenhouse accounts factors" DOC = 0.15 "fraction of degradable organic carbon - food waste" DOC_f = 0.84 "fraction of degradable organic carbon dissimilated for the waste type" F_I = 0.4374 "methane fraction of landfill gas - TCC is more like 0.44" R = 0 "recovered methane" OX = 0.1 "oxidation factor: 0 for uncovered, 0.1 for covered" "Fraction of methane flared at Stuart landfill" V_waste_ann = 481040/4.75 "[m^3/y] Waste volume per year" Density_waste_truck = 10/28 "[t/m^3]. Estimated by townsville waste services." Density_waste_landfill = 0.75 "[t/m^3]. Assumed" Emission_landfill_tot_ann = V_waste_ann*Density_waste_landfill*(1.4+1.3*(1-0.075)/2+0.2*0.075) "[t CO2-e/y]=[m^3/y]*[t/m^3]*[t CO2-e/t waste]. Annual landfill emissions assuming 7.5% industrial and remainder a 50/50 mix of municipal/commercial-industrial waste based on NGAF" V_emission_landfill_tot_ann = (Emission_landfill_tot_ann*1000*1000/(12+16*2))*8.314*298/1.01325 "[m^3 CO2-e/y]=[t CO2-e/y]*[1E6g/t]/[44g/mol]*[8.314 m^3.bar/mol.K]*[298 K]/[1.01325 bar]. Ideal gas law: V=nRT/P. " V_flared = 2885348/(12+4*1)*(12+2*16) "[m^3 CO2/y] = [m^3 CH4/y]/MM_CH4*MM_CO2" V_fraction_flared = V_flared/V_emission_landfill_tot_ann "fraction of CO2-e emitted which gets flared" "Total landfill emissions which would occur from organic waste deposits" Emission_landfill_organics = (m_waste_organic*DOC*DOC_f*F_I*1.336 - R)*(1-OX)*25*(1-V_fraction_flared) "[t CO2-e]" conversion_3 = Emission_landfill_organics/m_waste_organic "[t CO2-e/ t food waste] based on national greenhouse accounts factors full calculation" "-------------------- COMBINED CO2-e (if organics were'nt recycled) --------------------" Emission_organics = Emission_landfill_organics + Emission_transport_org Compost_emission_ratio = Emissions_compost/Emission_organics Emissions_transport_percent = Emission_transport_org/Emission_organics*100 conversion_tot = Emission_organics/m_waste_organic "[t CO2-e/t organic waste]"
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Emissions_offset = Emission_organics + Emission_nutrient_offset - Emissions_compost
