SoilMill PGH is a pilot project led by the Department of City Planning, Department of Public Works, and Citiparks that seeks to improve soil quality in Pittsburgh through composting.

Phase I concluded in December 2024. Take a look at the Phase I final report in the Document Library.

Phase I was funded by a $90,000 grant from the United States Department of Agriculture, with additional support granted from Natural Resources Defense Council - Food Matters, Pennsylvania Resources Council, and City of Pittsburgh's Clean Pittsburgh Commission.

Interested in talking trash? Engage with us through the comprehensive plan "Summer of Engagement," where you'll have the opportunity to improve how we manage organic waste, construction waste, recycling, litter, composting, and more.

Building on the lessons learned from Phase I of SoilMill PGH, Phase II digs deeper into the practical, budgetary, spatial, and structural requirements for managing organic waste at a larger scale and activating additional components of the City's Zero Waste Plan.

With funding from the US Conference of Mayors and the support of Pittsburgh's city council and the Congress of Neighboring Communities (CONNECT), the city will address the planning, infrastructure, and regional challenges of deploying a waste management plan that includes composting.

Components of Phase II are:

• A Request for Qualifications for organic waste storage, processing, hauling, IoT logistical, and educational services. The Request for Qualifications: Food Scrap and Organic Waste Systems Management is accepting responses until May 23, 2025.
• A Request for Proposals for assistance with updating Pittsburgh's existing Zero Waste plan and the creation of a strategic Roadmap to Municipal Composting for Pittsburgh. RFP scheduled to be announced Summer, 2025. Interested consultants are encouraged to subscribe to Open Gov Pittsburgh to receive notice of the announcement.
• Regional waste planning for municipalities in Allegheny County, hosted by CONNECT's Materials Management and Composting working group.
• Community engagement for Composting, hosted by the Food Policy Council's Urban Agriculture Working Group
• Community engagement for waste, hosted by Pgh 2050, Waste Working Group.

Compost is broken down organic matter that is used as a natural fertilizer for soil. Composting is the process by which compost is formed. All organic matter can be composted given the right system and conditions and anyone can do it.

Compost can be produced through large-scale industrial processes, at community gardens, in a back yard, or simply in the corner of someone's kitchen. There are different kinds of composting but the same general process is used in each: organic waste is placed into a vessel or heap, that waste undergoes some sort of "turning" to mix and introduce air. Biological and chemical processes naturally occur in the pile allowing heat to build up to break down the organic waste. Eventually, this processing produces the final product, compost. When done correctly, compost smells earthy like soil or possibly vinegar. Composting is a great way to reduce greenhouse gasses, give food waste a new purpose, and increase soil quality without adding chemicals or unnatural additives to the earth.

Food Waste

Every year 89,000 tons of edible food waste end up in U.S. landfills. Composting is one of the best ways to reduce the amount of food thrown away.

General outreach shows there are many people interested in reducing the amount of food they send to the landfill, but do not have the resources or knowledge to get started. There are also community groups in Pittsburgh that participate in composting, but the scope of their work is unknown. Lastly, there are larger organizations aiming to reduce food waste by connecting healthy food surpluses to the people in need, but right now, there are only limited connections between existing efforts. The SoilMill PGH pilot aims to connect and strengthen these projects to reduce overall food waste in Pittsburgh.

Soil Quality

Industrial processes have drastically decreased the soil quality in Pittsburgh. Years of heavy metal and chemical deposits have increased toxin levels and the acidity of the soil, therefore decreasing the nutritional value of the food grown in it and adding to increased levels of harmful air and soil exposures to substances like lead. In addition, the steep slopes in the area and high volume of shale and clay limit the root holding availability of plants, decreasing the actual land space that can grow food or hold enough water to protect against erosion.

Composting is a great way to recharge local soils. The decomposing matter releases vital nutrients that new plants are able to absorb and provide to the consumer as thriving landscapes and nutritious food. Compost also can neutralize soil acidic over time by adding materials that help correct pH, dilute contamination levels, filter air, and allow treated soil to better act as a natural carbon sink reversing the impacts of climate change.

Zero Waste Farmers' Markets & Park Shelters

Farmers' Markets

The City provided farmers' market vendors with initial compostable materials to test. The goal: Transition to zero waste markets and assist vendors with identifying affordable and reliable compostable options.

Parks' Shelters and City-Owned Centers

The City worked towards activating its Sustainable Event Guide to identify park shelters that could benefit from composting. The goal: Work towards helping shelter renters reduce the volume and weight of waste from their private events, prevent litter, discourage insect/animal scavengers, maintain the quality of our shelters, and safeguard the health and natural beauty of our park's plants and animals. For the purposes of our pilot, we reviewed composting sites with PGH LAB partner, Ecotone Renewables and the Department of Public Works.

Community Pilots

Homewood Healthy, Active Living Center

Homewood's Healthy, Active Living Center is one of our many senior centers that provide seniors with vibrant recreational opportunities. Not only do our centers help keep our seniors busy, they also serve as community-based heating and cooling oases during inclement weather events and offer affordable, healthy meal options. In an effort to expand our zero waste initiatives, during the pilot, after lunch was served and consumed, food waste was processed into soil sauce using Ecotone's digester at this site. The mechanical digester didn't require physical turning or one-on-one attention from staff. The staff was able to empty the waste and have a finished "compost tea" like product produced on site.

Resident, community-based composting systems pilot: SoilMill PGH

In year two of the pilot, the City was interested in testing the impact and effectiveness of existing and newly implemented community-based composting options and resources available to residents. To better assess community resources, wants, needs, and impacts, the City reached out to a pool of over 300 residents from around Pittsburgh to engage with us in a 20-week pilot. Of the 300 we reached out to, about 200 completed the full pilot. All participating residents received access to valuable tools, training, a 1.3 gallon countertop food scrap collection bin and two compostable 100% cotton carbon filters. These resources were provided in exchange for, at minimum, one hour of pilot training and agreeing to complete journals and respond to four feedback surveys throughout the pilot.

In our efforts to achieve citywide participation, we accepted residents from north, south, east, west, and central neighborhoods of Pittsburgh. Participants were selected based on their responses to the interest form and their locations were determined by their provided address and zip code.