Food-Waste to Compost SystemLaura Kramer
Community Based Food-Waste to Compost System
Laura A. Kramer
Biological Systems Engineering Department
University of Wisconsin-Madison
3/14/17
Table of Contents
Key Words
- Food-waste
- Compost
- Chemical fertilizer
- Community based
- Soil quality
Statement of Need
The value of organic matter has been appreciated for centuries. Civilizations as early as the Akkadian Empire (Diaz, Bertoldi, 2007) were known to have used manure and rotted straw as amendments to their garden soil however, since the advent of modern science the value of compost has been greatly reduced. Unfortunately, the dependence of modern agriculture on chemical fertilizer is not without consequence and the growing population is placing ever higher demands on the environment. As a result,environmentalists are beginning to take a closer look at composting and it myriad of benefits which include reduced landfill load, reduced dependency on chemical fertilizer, and increased awareness about wasteful consumption habits.
In Wisconsin alone there are eighty active landfill sites and together they offered a staggering 137,415,547 cubic yards of capacity in 2016 (Wisconsin DNR, 2016) that is about equivalent to 42,000 Olympic sized swimming pools. According the Environmental Protection Agency (2007) food waste accounts for 18% of the waste stream on average and is the second largest category of municipal waste. This means that about 24,734,798 cubic yards or 7,566 Olympic swimming pools worth of space could be saved by diverting food waste to a compost system. Such a solution would benefit the local communities and the space gained will become invaluable as the global population continues to rise. Current models estimate that global population will reach about 9 billion by 2050 (Food and Agriculture Organization, 2009). If this prediction is accurate, humanity cannot afford to waste valuable space on landfills when it could be used to build communities, grow food, or otherwise support the population.
Not only will a food waste to compost system create much needed space but it will simultaneously reduce the agriculture industry’s dependence on chemical fertilizer. Compostamendments offer many benefits to soil health which chemical fertliziers do not such as increased levels of organic matter, improved aggregate stability and enhanced soil microbe levels (Rivero, Chirenje, Martinez, 2004). Moreover, in 2004 researchers showed that compost amended soilds can lead to similar or even higher crop yeilds while reducing nutrient leaching and crop quailty (Hernandez, Chocano, Moreno, Garcia). Based upon these conlcusions compost has the potential to replace or at least supplement chemical fertilizer as the backbone of modern agriculture. This would decrease the negative effects of nitrogen pollution (EPA, 2017) from chemical fertilizers and provide farmers with an opportunity to become more self-sufficient by aquring a compost system of their own. Furthurmore, compost is completely organic and a food waste to compost system would support the rapid growth of the organic farming industry (Onwosi, et al., 2017).
Lastly, a food waste to compost system would make it easier for citizens to be socially responsible about their consumption habits. Creating a community based composting system would increase awareness about the subject of food waste and give people and insight as to how much unessecary waste they might be generating. About one quarter of the food supply is wasted over the course of it journey from farm to field and half of that occurs at the household level (Stancu, Haugaard, Lahteenmaki, 2015). While composting may not directly reduce the amount of waste being generated it may encourage consumers to be more responible in their decisions.
Although there are several potential systems on the market none of them fully satisfy the needs of our customer. For example, the Earth Tub. Produced by Green Mountain Technologies is an in vessel, aerobic composting system capable of composting up to 100 pounds per day. However, the earth tub requires electricity to run its internal auger therefore it is not an optimal design for our customers who have requested the system be non-grid powered. In fact, it would be best if the composter could be self-sustaining. One promising study noted that heat generated by the compost provides a reliable source of energy and has the potential to power the composter itself (Irvine et al.).
Another current market solution is the backyard composter. Such devices are widely available from any home and garden store however they are designed for a single household and are much too small for the system proposed here additionally, they usually require manual aeration making them ill-suited to our customers needs.
Project Goal
This project seeks to develop a low-costcommunity based system to transform seasonally variable quantities of food waste and carbon materials into high quality compost while minimizing labor requirements andnegative externalities such as odor, noise and pests.
Project Specifications
Capacity
1.)The system shall meet the food composting needs for 100 families. Preferably in a community setting the composter will be a central unit serving a whole neighborhood.
Structure
2.)The system should be insulated. This will help to increase temperature within the composting chamber thereby hastening the composting process.
3.)The system should be able to monitor its temperature and send updates to a computer or mobile device. If something goes awry an operator would be notified immediately.
4.)The system should be non-grid powered to reduce the cost of operation the system should be completely self-sufficient.
Safety
5.)The door to the composting chamber must be able to open from the inside as well as the outside to prevent someone becoming accidentally trapped inside.
6.)Must adhere to all neighborhood codes or local regulations as well as the regulations in Chapter 17 of the Solid Waste Management Code for the City of Milwaukee.
Operation and Maintenance
7.)The system must maintain proper carbon to nitrogen ratio and be aerobic to ensure compost of the highest quality
8.)The system must be simple enough for one person to operate minimizing labor expenditure
9.)The system must minimize odor and pests to avoid complaints from nearby residents
10.)The system should be capable of occasional mixing to maintain the aerobic state of the compost within
Economics
11.)The system must not exceed the target cost of $5,000
12.)The system must have minimum a lifetime of 10 years and be able to withstand exposure to the elements, seasonal temperature flocculation and ultra violet radiation.
Project Output
The end result of this project should be a small scale, working prototype with which further analysis can be conducted. The prototype will be used for field testing to simulate the composting process and to identify areas in need of improvement or change. In addition, this project should develop a complete three dimensional SolidWorks model to conduct mechanical stress analysis and calculate throughput capacities of a larger model.
Annotated Bibliography
Journal Articles
Diaz, L. F., & Bertoldi, M. D. (2007). History of Composting: Waste Management Series.Compost Science Technology,8, 7-24. Retrieved March 13, 2017, from
A brief summary of urban waste production and various methods by which to handle it. Explores the mechanization of waste handling and several experimental studies conducted on composting.
Erhart, E., Hartl, W., & Putz, B. (2005). Biowaste compost affects yield, nitrogen supply during the vegetation period and crop quality of agricultural crops.European Journal of Agronomy,23(3), 305-314. Retrieved March 13, 2017, from
Experimental analysis of the impact of organic compost on soil quality, structure, and productivity. Findings show that the compost efficacy increases with time and it acts as a slow release nitrogen source
E.R. Oviedo-Ocaña, I. Dominguez, P. Torres-Lozada, L.F. Marmolejo-Rebellón, D. Komilis, A. Sanchez, (2016). A qualitative model to evaluate biowaste composting management systems using causal diagrams: a case study in Colombia.Journal of Cleaner Production, 133, 201-211,
An analysis of the factors that impact the implementation of bio waste composting. It reviews the operation and findings of 5 composting facilities in Colombia over and eight year period.
Food and Agriculture Organization. (October, 2009). How to Feed the World in 2050.High Level Expert Forum. Retrieved from
In depth discussion about the global trends of population growth, agricultural productivity, and other environmental stresses that arise as a result of increased population. Facts and figures divided by geographical location.
Gregory Evanylo, Caroline Sherony, John Spargo, David Starner, Michael Brosius, Kathryn Haering. (August 2008) Soil and water environmental effects of fertilizer-, manure-, and compost-based fertility practices in an organic vegetable cropping system.Agriculture, Ecosystems & Environment,127(1–2) Pages 50-58,
Experimental analysis of the nutritional impact of compost on unhealthy soil. Findings show that crop yields did not benefit from compost but the soil saw improvements in bulk density and porosity indication compost benefits may increase with time
Grizzetti, B., Pretato, U., & Lassaletta, L. (2013). The contribution of food waste to global and European nitrogen pollution.Environmental Science & Policy,33, 186-195. Retrieved March 13, 2017, from
Estimate of the global nitrogen loss due to food wasted and of nitrogen delivered to the environment through food waste. Findings show that in the European Union 65% of food related nitrogen leaking ultimately ends up in the water supply.
Hernandez, T., & Chocoano, C. (2016). Use of compost as an alternative to conventional inorganic fertilizers in intensive lettuce (Lactuca sativa L.) crops—Effects on soil and plant.Soil and Tillage Research,160, 14-22. Retrieved March 13, 2017, from
Analysis of the diffusion of nitrogen through soil and how it is impacted by the use of compost as a fertilizer. Findings show that the use of compost in soil reduces the risk of nutrient leaking and is a viable alternative to chemical fertilizer.
Irvine, G., Lamont, E. R., & Lantizar-Ladislao, B. (2010). Energy from Waste: Reuse of Compost Heat as a Source of Renewable Energy.International Journal of Chemical Engineering,2010, 1-10. Retrieved March 13, 2017, from
In depth analysis of the feasibility of capturing heat from compost and using it as a source of renewable energy. Results show that such a system would provided a reliable source of energy to run the composter itself
Onwosi, C., Igbokwe, V., & Odimba, J. (2017). Composting technology in waste stabilization: On the methods, challenges and future prospects.Journal of Environmental Management,190, 140-157. Retrieved March 13, 2017, from
Overview of composting as a waste management technique and environmental factors effecting compost. Most importantly, a list of ways composting has the potential to be improved in the future including the capture and use of heat from the compost itself.
Rivero, C., Ma, L. Q., & Martinez, G. (2004). Influence of compost on soil organic matter quality under tropical conditions.Geoderma,123(3-4), 355-361. Retrieved March 13, 2017, from
A field study conducted in Puerto Rico evaluating the impact of compost on soil quality and crop yield.
Sidder, A. (2017, September 9). The Green, Brown, and Beautiful Story of Compost.National Geographic. Retrieved March 13, 2017, from
An overview of the history of composting from its inception in ancient times to pre-industrialization. A brief description of small versus large scale operations and how an average homeowner might begin to compost.
Zhao, J., & Et. al. (2016). Effects of organic–inorganic compound fertilizer with reduced chemical fertilizer application on crop yields, soil biological activity and bacterial community structure in a rice–wheat cropping system.Applied Soil Ecology,99, 1-12. Retrieved March 13, 2017, from
Experimental analysis of organic-inorganic fertilizer as it relates to soil health and microbial growth. Findings show that compost has the potential to replace chemical fertilizer in the modern agriculture industry.
Government Laws, Codes, and Regulations
City of Milwaukee. (2016, March 29). Solid Waste Regulations. Retrieved March 13, 2017, from
Chapter 79 of the City of Milwaukee's code on solid waste management.
Miscellaneous Publications
Duke University. (2017). How much do we waste daily? Retrieved March 14, 2017, from
Quick facts and figures about the average daily waste produced by a typical American citizen. Paragraph of suggestions about what individuals can do to reduce their waste.
Earth Tub – Green Mountain Technologies. (n.d.). Retrieved March 14, 2017, from
Home website for the Earth Tub. Includes thorough description of purpose, design, applications, and assembly of the Earth Tub.
EPA. (2016, February 23). Reducing Food Waste. Retrieved March 14, 2017, from
Facts and figures on national municipal waste stream averages. Pie chart describing categories and percentages of the municipal waste stream and how individuals and reduce their waste production.
EPA. (2017, March 10). Nutrient Pollution: The Problem. Retrieved March 14, 2017, from
Discussion of nutrient pollution across America and its environmental, economic and health effects. The focus is on nitrogen pollution and its sources.
Hoefs, J. (2013, August 20). Measurements for an Olympic Size Swimming Pool. Retrieved March 14, 2017, from
Simpson, S. (2009, March 20). Nitrogen Fertilizer: Agricultural Breakthrough--And Environmental Bane. Retrieved March 14, 2017, from
Early history of chemical fertilizer and the green revolution. A comprehensive discussion about the detrimental effects overuse of chemical fertilizer on the environment and the predicted outcome of continued use. A look at how the renewable energy industry may be part of the problem.
Wisconsin, D. (2016, August). 2015 Municipal and Industrial Waste Landfill Tonnage. Retrieved March 13, 2017, from
A table summarizing each certified and operating landfill in Wisconsin, the capacity in cubic meters and the quantity in tons each landfill receives.
Data on volume and features of Olympic sized swimming pools.
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