Composting

There is strong evidence that composting food waste improves soil health (Brichi 2023, Palansooriya 2023, Thakur 2022, Kranz 2020, Sayara 2020, De Corato 2020), increases soil carbon content and carbon sequestration (Malone 2023, Gravuer 2019, Brichi 2023), and reduces emissions, especially by averting methane emissions from landfills (Huang 2022, Mckenzie 2022, Brown 2016b, Lou 2009).

Soil health. Composting improves soil fertility, microbial and enzymatic activity, nutrient content, and physical properties, including density and porosity (Palansooriya 2023, Brichi 2023, Huang 2022, Sayara 2020, De Corato 2020). Composting can reduce soil contaminants, pathogens, and plant diseases (Palansooriya 2023, Brichi 2023, Thakur 2022, De Corato 2020, De Corato 2020a) and reduce soil erosion and eutrophication of waterways (Huang 2022). Applications of compost and other soil amendments can help reclaim salt-affected soils and return degraded soils to productive agricultural use (Leogrande 2019). High-quality compost applications can help remediate soils contaminated with heavy metals, microplastic pollution, and other hazardous pollutants (Malone 2023, Yao 2023, Huang 2016a). Composting can reduce the availability, mobility, and ecological risk of hazards in the soil, increase the effectiveness of phytoremediation or using plants to clean up soil contaminants, and help dilute and break down some micropollutants (Malone 2023, Yao 2023, Huang 2016a). Vermicomposting and using soil amendment additives can increase the effectiveness of compost remediation (Malone 2023, Huang 2016a).

Soil carbon content. Composting increases carbon and nitrogen conservation in the soil, preventing carbon and nitrogen from accumulating in the atmosphere as greenhouse gases, especially carbon dioxide and nitrous oxides (Malone 2023, Huang 2022, Gravuer 2019, Lou 2009). Composting increases soil’s water retention and decreases run-off, which improves carbon sequestration, plant health (De Corato 2020, Gravuer 2019), and crop productivity (Brichi 2023). Composting supports plant growth and increases carbon dioxide uptake and storage within plants (Lou 2009). Available evidence shows that composting to reduce food waste has the potential to provide large scale reductions to atmospheric carbon (Leu 2014, Project Drawdown-Food waste, Project Drawdown-Composting). Organic and regenerative farming practices use composting and have been shown to increase soil carbon and provide higher carbon sequestration than conventional farming (Leu 2014, Gattinger 2012, Project Drawdown-Reg Ag). Farming practices including composting are also a suggested strategy for adaptation to climate change, since they are more resilient, more efficient with water use, and provide higher yields in drought years than conventional farming practices (Leu 2014, Project Drawdown-Reg Ag).

Emissions effects. Removing food scraps from landfills and diverting them to compost is a highly effective way to avoid methane gas production (Brown 2016b, Mckenzie 2022). By improving soil physical structure, compost makes the soil more workable, which can further reduce emissions by reducing fossil fuel use to work the soil (Lou 2009). Applying compost to soil reduces fertilizer and herbicide use (Huang 2022), which further reduces greenhouse gas emissions from the production and application of those fertilizers and pesticides (Lou 2009). Source separation of municipal solid waste requires heavy machinery to separate, grind, mix, and aerate compostable materials, which requires energy and produces greenhouse gas emissions (Lou 2009). Sorting compostable food and yard waste before collection reduces these issues and produces a higher quality compost product without contamination from contact with other waste (Cerda 2018).

Vermicomposting. Vermicomposting can provide even greater benefits than traditional aerobic composting, with a faster process, more nutrient-rich final product, greater effects on disease suppression (Yatoo 2021), and increased removal of heavy metals and toxic substances (Mohee 2014). Vermicomposting can also be adapted for use on the biodegradable portion of municipal solid waste, including food, paper, and green waste (Ducasse 2022) and vermicomposting of municipal solid waste reduces bacteria and pathogen loads from final compost product (Soobhany 2017).

Urban area effects. Composting efforts in urban areas can improve soil health and increase soil carbon storage (Malone 2023, Kranz 2020). Composting improves physical properties of degraded, compacted urban soil such as bulk density and water infiltration, which reduces run-off and erosion, and makes it easier for plants to grow (Kranz 2020). Composting to improve soil health in urban areas provides many co-benefits, including increasing urban green space, which can reduce heat island effects and improve mental health; improving urban gardening, which can improve local food security and food quality; supporting productive and sustainable community gardens; and remediating soil by reducing the availability of lead, arsenic, and other contaminants in the soil for plants to absorb (Malone 2023). Additional research is needed on compost application rates, depth of incorporation, and concentrations to achieve the greatest improvements in urban soil physical properties (Kranz 2020).

Best practices. Compost quality is affected by the waste source, raw materials used, and variables during the composting process (Azim 2018). Implementing a system to sort and collect food waste for compost that is separate from municipal solid waste can prevent heavy metal, microplastic, and toxic substance contamination (Huang 2016a) and reduce the need for waste pretreatment and subsequent odors and bioaerosols (Cerda 2018, Wei 2017). Ensuring compost maturity and stability prior to soil application increases benefits to soil quality, improves stable carbon storage, and improves plant health benefits (Sayara 2020, Azim 2018). Compost processes that use physical, chemical, and microbial additives, increase aeration, and include pretreatment can improve nitrogen retention and reduce soil nitrous oxide emissions; these efforts are more necessary for municipal solid waste composting than pre-sorted food waste composting (Shan 2021, Wang 2018c). Composting benefits can be maximized with site specific application strategies that account for past land use, current conditions, and future uses (Gravuer 2019). Composting can be time consuming and compost practices need to monitor compost piles to ensure that food waste addition does not create overly wet conditions that can lead to anaerobic decomposition that produces methane. The use of brown leaves or yard waste, shredded paper, bulking agents, and other additives can improve structure to facilitate oxygen incorporation and can improve nitrogen and carbon balance to prevent anaerobic decomposition (Palansooriya 2023).

Costs and scale. Composting can be implemented effectively at almost any scale, from home composting to large city-wide treatment facilities (Sayara 2020). Experts calculate that composting costs less than landfill waste disposal for food waste. The cost of establishing new composting facilities is less than the cost of establishing new landfills, and though operating costs for large scale compost facilities are higher than those for landfills, composting also generates revenue with the sale of the finished product. Regulations, space, and logistic constraints can increase the costs of landfill expansion, which makes composting even more cost effective (Project Drawdown-Composting). Home composting is inexpensive to establish, requires minimal equipment, and can improve home or community gardens and save money that would have been spent on fertilizers and pesticides (US EPA-Composting). In the U.S. developing a circular economy to sustainably manage food throughout its life cycle at the production, processing, transportation, consumption, and waste stages can conserve resources, save money, and improve food access (US EPA-Food management).

Life cycle analysis suggests composting provides more environmental benefits and climate change impact reductions than other organic waste disposal methods such as sending waste to the landfill or waste-to-energy projects (Huang 2022).

Experts suggest composting has the potential to decrease disparities in exposure to landfill waste and soil contaminants between those with lower incomes and those with higher incomes, and to support environmental justice in communities with fewer resources, which experience disinvestment and are overburdened by environmental hazards (TRF-Hamilton 2023, Yale-Silver 2022, ILSR-Brolis 2022, Malone 2023). Available data shows waste management facilities including landfills, waste incinerators, and legal and illegal hazardous waste sites, are disproportionately located in communities with more residents of color and people with low incomes (Martuzzi 2010). Conventional waste management practices disproportionately impact the well-being and health of communities of color with low incomes (Martuzzi 2010). Experts suggest composting initiatives can change and improve equity in waste management, food systems, environmental exposures, and climate change effects, using community participation to develop local collection, composting, and distribution systems (ILSR-Brolis 2022).

Experts recommend integrating food and waste justice initiatives to create equitable policies and contracts for all communities (Hall 2023). Case studies suggest communities have inequitable access to mature, high-quality compost (Hall 2023). Many urban communities would benefit from community composting and city compost services, especially if the compost is sourced from food waste, that was picked up separately, tested, and delivered to community gardens and public green spaces (Hall 2023, BioCycle-Sierra 2022). Such systems could improve the safety and equity of organic waste-to-compost cycles (Hall 2023). Experts suggest high-quality compost would be especially beneficial if provided to community gardens and urban agriculture initiatives that serve people with low incomes, experiencing food insecurity, and working in neighborhoods with soil that needs revitalization and remediation (Hall 2023). Local and state legislation can support sharing safe, nutrient-rich compost in structurally disadvantaged communities (Hall 2023).

A Baltimore case study suggests local composting can be used to support local tree planting initiatives to reduce urban heat island effects that disproportionately impact formerly redlined neighborhoods with residents of color and with lower incomes (BioCycle-Sierra 2022).

Composting has always been a part of nature’s waste disposal system and since the beginning of human history there is evidence that many societies have valued compost as a fertilizer (Larum 2022, TO-Compost 2015). In the early 1900s, however, companies began to produce chemical fertilizers that almost entirely replaced compost. By 1950, estimates suggest that 99% of the fertilizer used in the U.S. was from chemicals instead of compost (TO-Compost 2015). Compost was minimally used until the 1960s, when an era of increased environmental consciousness made organic farming and composting more popular (TO-Compost 2015). In the 1980s, recognition that the U.S. was generating too much waste increased interest in recycling, yard waste composting, and environmental laws to regulate industrial waste disposal and to protect humans and wildlife from chemical fertilizers and pesticides, which increased composting efforts in many industries and among many farmers (TO-Compost 2015).

The U.S. generated close to 300 million tons of municipal solid waste in 2018 (US EPA-National overview). Of that only 25 million tons were composted, which included 22.3 million tons of yard waste and 2.6 million tons of food waste (US EPA-National overview). According to the U.S. Environmental Protection Agency (U.S. EPA), almost 25% of all municipal solid waste is food waste. Over 51% of municipal solid waste sent to landfills is compostable, including yard waste and biodegradable wood, paper, and cardboard (US EPA-SMF). The U.S. EPA estimates over 66 million tons of food was wasted in 2019 in food retail, food service, and homes, and only 5% of that food waste was composted (US EPA-SMF).

• Which neighborhoods in your community do not have composting services or access to high-quality compost for public or private gardening or greening initiatives?
• What infrastructure, services, tools, or educational resources are needed to help your local community develop or increase participation in composting programs?
• How can your community composting services support local needs for soil remediation, reducing run-off, greening initiatives, gardening, urban agriculture, or climate change mitigation and adaptation? What outreach activities could raise awareness about composting benefits and composting opportunities, to increase participation?
• Who makes decisions about composting services in your community? How is your community engaging residents and stakeholders from neighborhoods experiencing environmental injustice and disproportionate burdens from society’s waste system to develop and plan composting initiatives that change the current food and waste systems?

California (CA-Organic waste), Connecticut (CT DEEP-Composting), Maryland (MD DOE-Composting), Massachusetts (MA DEP-Composting), New Jersey (NJ DEP-Sustainable waste, NJCC), New York (NY DEC-Composting), Rhode Island (RIRRC-State laws), Vermont (VT DEC-Food scraps), and Washington (WA DEE-Organics management) are the nine states with laws that regulate sending organic waste to composting facilities instead of to landfills (Vasilogambros 2023). Several states have grants available to support additional composting efforts; for example, the Maryland State Department of Education has grants for schools starting food waste reduction and composting programs (MD ED-School composting) and the California Department of Resources Recycling and Recovery offers grants for small-scale composting projects for green spaces in disadvantaged communities (CalRecycle-Compost grants). The U.S. Composting Council is a national organization with 16 state chapters that support compost manufacturing and use for the benefits it provides to soil, air, and water quality, and to climate stabilization (US CC). The U.S. Composting Council also offers a searchable database of state regulators and regulations that affect composting efforts (US CC-State database).

Several cities in the U.S. have successful, mandatory composting programs, including San Francisco (SFE-Composting); Portland, Oregon (Portland-Compost); Boulder and Denver, Colorado (Boulder-Zero waste, Denver-Zero waste); and Seattle (Seattle-Food waste). San Francisco was the first U.S. city to establish a city-wide composting program in 1996 and currently composts and recycles roughly 80% of its waste (GM-Rosenberg 2020). Many cities are implementing composting pilot programs, including Boston, Pittsburgh, and Jacksonville, Florida (Vasilogambros 2023). New York City has also passed a new Zero Waste Act that includes mandatory composting programs with curbside pickup, universal composting for all residential buildings, increased organic waste drop off locations, and expanded compost facilities increasing equitable access to composting across the five boroughs (NYCC-Zero waste 2023).

At the federal level, grants are available that support initiatives to reduce food waste and increase composting opportunities, for example, the U.S. Department of Agriculture’s Composting and Food Waste Reduction Cooperative Agreements help local and city governments develop and implement community composting plans (USDA-CFWR). The Inflation Reduction Act of 2022 includes Greenhouse Gas Air Pollution Plans and Implementation Grants and the U.S. Environmental Protection Agency administers the Solid Waste Infrastructure for Recycling Grant Program; both grant programs can support composting initiatives (ZFWC-State policy toolkit 2023).

Composting initiatives are operated by many non-profit organizations across the country. For example, Conservation Works operates the Waste Wizards program in Northern California that teaches children about composting and reducing food waste to reduce climate change effects and diverts food waste from school cafeterias to create compost (CW-Food waste). Many community composting projects are equity-focused initiatives; for example, the Baltimore Compost Collective. This project is located on an acre of land in the Curtis Bay neighborhood that has experienced environmental injustice. The land was once polluted and now is home to a healthy community garden with 47 individual plots, beehives, goats, and ducks. The Baltimore Compost Collective is also building the nation’s largest municipally-managed compost facility and using composting to support environmental justice in disadvantaged neighborhoods, offer job training for youth, and reduce greenhouse gas emissions (TRF-Hamilton 2023).

FWA-Compost resources - Food Well Alliance (FWA). Compost resources list and resource guide.

ILSR-Composting podcast - Institute for Local Self-Reliance (ILSR). Composting for community podcast.

NRDC-Hu 2020 - Hu S. Composting 101. National Resources Defense Council (NRDC). 2020.

NRDC-Mugica 2019 - Mugica Y, Rose T. Tackling food waste in cities: A policy and program toolkit. National Resources Defense Council (NRDC), The Rockefeller Foundation. 2019.

Project Drawdown-Composting - Project Drawdown. Climate solutions: Composting.

Project Drawdown-Reg Ag - Project Drawdown. Climate solutions: Regenerative annual cropping.

US EPA-CCFS toolkit - U.S. Environmental Protection Agency (US EPA). (n.d.). Composting food scraps in your community: A social marketing toolkit.

US EPA-Composting - U.S. Environmental Protection Agency (US EPA). Composting at home.

USDA-Composting - U.S. Department of Agriculture (USDA). Composting.

ZFWC-State policy toolkit 2023 - Zero Food Waste Coalition (ZFWC). Achieving zero food waste: A state policy toolkit. May 2023.

* Journal subscription may be required for access.

Azim 2018* - Azim K, Soudi B, Boukhari S, et al. Composting parameters and compost quality: A literature review. Organic Agriculture. 2018;8:141-158.

BioCycle-Brown 2024 - Brown, S. (2024, September 17). Connections: Vector attraction 101. BioCycle.

BioCycle-Sierra 2022 - Sierra A, Hosain S. Local composting integral to reducing urban heat island impacts. BioCycle. September 13, 2022.

Boulder-Zero waste - City of Boulder, Colorado. Universal zero waste ordinance.

Brichi 2023* - Brichi L, Fernandes JVM, Silva BM, et al. Organic residues and their impact on soil health, crop production and sustainable agriculture: A review including bibliographic analysis. Soil Use and Management. 2023;39(2):686-706.

Brown 2016b* - Brown S. Greenhouse gas accounting for landfill diversion of food scraps and yard waste. Compost Science and Utilization. 2016;24(1):11-19.

CA-Organic waste - State of California, CalRecycle. New statewide mandatory organic waste collection.

CalRecycle-Compost grants - California Department of Resources Recycling and Recovery (CalRecycle). California climate investments: Community composting for green spaces grant.

Cerda 2018* - Cerda A, Artola A, Font X, et al. Composting of food wastes: Status and challenges. Bioresource Technology. 2018;248:57-67.

CT DEEP-Composting - Connecticut Department of Energy & Environmental Protection (CT DEEP). Composting and organics recycling.

CW-Food waste - Conservation Works (CW). Waste Wizards composting program: Conservation Works climate change & fire resiliency activities: Addressing food waste.

DCWR-Composting - Dane County Department of Waste & Renewables (DCWR). Composting in Wisconsin.

De Corato 2020* - De Corato U. Agricultural waste recycling in horticultural intensive farming systems by on-farm composting and compost-based tea application improves soil quality and plant health: A review under the perspective of a circular economy. Science of the Total Environment. 2020;738:139840.

De Corato 2020a* - De Corato U. Disease-suppressive compost enhances natural soil suppressiveness against soil-borne plant pathogens: A critical review. Rhizosphere. 2020;13:100192.

Denver-Zero waste - City of Denver, Colorado. Zero waste: Recycle, compost, and trash.

Ducasse 2022 - Ducasse V, Capowiez Y, Peigné J. Vermicomposting of municipal solid waste as a possible lever for the development of sustainable agriculture. A review. Agronomy for Sustainable Development. 2022;42:89.

FAO-Food waste - Food and Agriculture Organization of the United Nations (FAO). Food wastage footprint & climate change.

Gattinger 2012* - Gattinger A, Muller A, Haeni M, et al. Enhanced top soil carbon stocks under organic farming. Proceedings of the National Academy of Sciences of the United States of America. 2012;109(44):18226-18231.

GM-Rosenberg 2020 - Rosenberg L. These are the biggest composting cities in the U.S. Green Matters (GM). November 17, 2020.

Gravuer 2019 - Gravuer K, Gennet S, Throop HL. Organic amendment additions to rangelands: A meta-analysis of multiple ecosystem outcomes. Global Change Biology. 2019;25(3):1152-1170.

Hall 2023* - Hall J, Khanjar N, Seyoum G, et al. 20 years of environmental injustice and the Mississippi hog industry: Spatial and statistical analyses for low-wealth communities and communities of color. Environmental Justice. 2023.

Huang 2016a* - Huang M, Zhu Y, Li Z, et al. Compost as a soil amendment to remediate heavy metal-contaminated agricultural soil: Mechanisms, efficacy, problems, and strategies. Water, Air, and Soil Pollution. 2016;227:359.

Huang 2022* - Huang D, Gao L, Cheng M, et al. Carbon and N conservation during composting: A review. Science of the Total Environment. 2022;840:156355.

ILSR-Brolis 2022 - Brolis LB. Composting for community podcast: Catalyzing greater equity through composting. Institute for Local Self-Reliance (ILSR). September 19, 2022.

Kranz 2020* - Kranz CN, McLaughlin RA, Johnson A, Miller G, Heitman JL. The effects of compost incorporation on soil physical properties in urban soils – A concise review. Journal of Environmental Management. 2020;261:110209.

Larum 2022 - Larum D. How old is composting: Learn about the origins of composting. Gardening Know How. 2022.

Leogrande 2019* - Leogrande R, Vitti C. Use of organic amendments to reclaim saline and sodic soils: A review. 2019;33(1):1-21.

Leu 2014* - Leu A. The potential for mitigation and adaptation to climate change with soil organic matter increases in organic production systems. Acta Horticulturae. 2014;1018:75-82.

Lou 2009* - Lou XF, Nair J. The impact of landfilling and composting on greenhouse gas emissions - A review. Bioresource Technology. 2009;100(16):3792-3798.

MA DEP-Composting - Massachusetts Department of Environmental Protection (MA DEP). Composting & organics.

Malone 2023 - Malone Z, Berhe AA, Ryals R. Impacts of organic matter amendments on urban soil carbon and soil quality: A meta-analysis. Journal of Cleaner Production. 2023;419:138148.

Martuzzi 2010 - Martuzzi M, Mitis F, Forastiere F. Inequalities, inequities, environmental justice in waste management and health. European Journal of Public Health. 2010;20(1):21-26.

Mckenzie 2022* - Mckenzie I, Diana S, Jaikishun S, Ansari A. Comparative review of aerobic and anaerobic composting for the reduction of organic waste. Agricultural Reviews. 2022;43(2):234-238.

MD DOE-Composting - Maryland Department of the Environment (MD DOE). Organics diversion and composting.

MD ED-School composting - Maryland State Department of Education (MD ED). School waste reduction and composting program.

Mohee 2014* - Mohee R, Soobhany N. Comparison of heavy metals content in compost against vermicompost of organic solid waste: Past and present. Resources, Conservation and Recycling. 2014;92:206-213.

NJ DEP-Sustainable waste - State of New Jersey, Department of Environmental Protection (NJ DEP), Division of Sustainable Waste Management. Food waste recycling and food waste-to-energy production law.

NJCC - New Jersey Composting Council (NJCC). Compost climate change connection and food waste recycling law.

NY DEC-Composting - New York State Department of Environmental Conservation (NY DEC). Composting.

NYCC-Zero waste 2023 - New York City Council (NYCC). City Council Sanitation Chair Sandy Nurse, council members Shahana Hanif and Keith Powers pass the landmark Zero Waste Act. June 8, 2023.

Palansooriya 2023* - Palansooriya KN, Dissanayake PD, Igalavithana AD, et al. Converting food waste into soil amendments for improving soil sustainability and crop productivity: A review. Science of the Total Environment. 2023;881:163311.

Portland-Compost - City of Portland, Oregon. Garbage, recycling, and compost: History of Portland's garbage and recycling system.

Project Drawdown-Composting - Project Drawdown. Climate solutions: Composting.

Project Drawdown-Food waste - Project Drawdown. Climate solutions: Reduced food waste.

Project Drawdown-Reg Ag - Project Drawdown. Climate solutions: Regenerative annual cropping.

RIRRC-State laws - Rhode Island Resource Recovery Corporation (RIRRC). State waste & recycling laws.

Sayara 2020 - Sayara T, Basheer-Salimia R, Hawamde F, Sánchez A. Recycling of organic wastes through composting: Process performance and compost application in agriculture. Agronomy. 2020;10(11):1838.

Seattle-Food waste - City of Seattle, Washington, Seattle Public Utilities. Food waste requirements.

SFE-Composting - San Francisco Environment Department (SFE). Recycling and composting in San Francisco: FAQs.

Shan 2021* - Shan G, Li W, Gao Y, Tan W, Xi B. Additives for reducing nitrogen loss during composting: A review. Journal of Cleaner Production. 2021;307:127308.

Soobhany 2017* - Soobhany N, Mohee R, Garg VK. Inactivation of bacterial pathogenic load in compost against vermicompost of organic solid waste aiming to achieve sanitation goals: A review. Waste Management. 2017;64:51-62.

Thakur 2022 - Thakur R, Verma S, Gupta S, Negi G, Bhardwaj P. Role of soil health in plant disease management: A review. Agricultural Reviews. 2022;43(1):70-76.

TO-Compost 2015 - Texas Organics. The history of compost. 2015.

TRF-Hamilton 2023 - Hamilton M. Grantee impact story: Composting for the climate and environmental justice. The Rockefeller Foundation (TRF). 2023.

US CC - U.S. Composting Council (U.S. CC). The voice of the compost industry.

US CC-State database - U.S. Composting Council (U.S. CC). State regulators and regulations: Searchable state database.

US EPA-ATC - U.S. Environmental Protection Agency (US EPA). (n.d.). Approaches to composting.

US EPA-CC - U.S. Environmental Protection Agency (US EPA). Community composting (CC).

US EPA-Composting - U.S. Environmental Protection Agency (US EPA). Composting at home.

US EPA-Food management - U.S. Environmental Protection Agency (U.S. EPA). Sustainable management of food basics.

US EPA-National overview - U.S. Environmental Protection Agency (U.S. EPA). National overview: Facts and figures on materials, wastes, and recycling: Composting or other food management.

US EPA-SMF - U.S. Environmental Protection Agency (U.S. EPA). Sustainable management of food: Composting.

USDA-CFWR - U.S. Department of Agriculture (USDA). Composting and Food Waste Reduction (CFWR) cooperative agreements.

Vasilogambros 2023 - Vasilogambros M. Save your food scraps, save the Earth: More cities and states look into composting. New Hampshire Bulletin. June 22, 2023.

VT DEC-Food scraps - Vermont Agency of Natural Resources, Department of Environmental Conservation (VT DEC). Food scraps.

WA DEE-Organics management - State of Washington Department of Ecology (WA DOE). Organics & food waste: Organics management law.

Wang 2018c* - Wang S, Zeng Y. Ammonia emission mitigation in food waste composting: A review. Bioresource Technology. 2018;248:13-19.

Wei 2017* - Wei Y, Li J, Shi D, et al. Environmental challenges impeding the composting of biodegradable municipal solid waste: A critical review. Resources, Conservation and Recycling. 2017;122:51-65.

Yale-Silver 2022 - Silver W, Abott-Lum F. Yale experts explain composting. Yale Sustainability. 2022.

Yao 2023 - Yao, X., Saikawa, E., Warner, S., D’Souza, P. E., Ryan, P. B., & Barr, D. B. (2023). Phytoremediation of Lead‐Contaminated Soil in the Westside of Atlanta, GA. GeoHealth, 7(8), e2022GH000752.

Yatoo 2021 - Yatoo AM, Ali MN, Baba ZA, Hassan B. Sustainable management of diseases and pests in crops by vermicompost and vermicompost tea. A review. Agronomy for Sustainable Development. 2021;41:7.

ZFWC-State policy toolkit 2023 - Zero Food Waste Coalition (ZFWC). Achieving zero food waste: A state policy toolkit. May 2023.