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2018 Illinois Institute of Technology Waste Audit Findings

Working with Plant Chicago, a group of students from Dr. Weslynne Ashton’s ‘Industrial Ecology and Systems Thinking’ class at IIT’s Stuart School of Business conducted Waste Audits and Material & Energy Flow Analyses on five businesses based inside The Plant. Plant Chicago was especially interested in this project because of the possibility to learn 1) how “circular” businesses inside The Plant already are, and 2) what opportunities might exist for business owners in the building to implement circular economy practices.

Although we sometimes affectionately refer to a waste audit as a fun excuse to dig through some trash, it is, in fact, a tool used to help analyze the efficiency of a process or business. It involves the categorization and measurement of all of the outputs of a process over a defined period of time.

Before conducting their waste audits, the students conducted Material & Energy Flow Analyses (MEFAs). MEFAs categorize and quantify the inputs (materials and energy) consumed and processes used by a business. For this specific project, each participating business provided information to Dr. Ashton’s students to help them better understand the businesses’ inputs and operational processes. When used in conjunction with waste audits, MEFAs can help provide a comprehensive picture of the flow of energy and materials through and within a business.

A majority of business owners carefully track their inputs, production processes, and final product outputs. However, most small businesses do not track their “waste” outputs (i.e. everything that does not go into their final salable goods). Waste audits can help a business understand the outputs they produce. In a circular economy, the next step is to figure out what can be reduced, recycled, reused, repurposed, or otherwise diverted from the waste stream.

Dr. Ashton’s students used the following guiding questions when conducting their MEFAs and waste audits:

  1. What are the material and energy requirements for operating the business?

  2. How efficiently are material and energy resources being used?

  3. What is the potential for improving resource productivity?

  4. How can the business save money?

How does a waste audit work?

To facilitate this particular waste audit, participating businesses collected their waste for one week. The waste stream was then audited by Dr. Ashton’s students. The students focused on sorting waste streams into three categories: compostable materials, recyclable materials, and materials that are neither able to be composted nor accepted for recycling by The Plant‘s current waste management provider.  Each waste stream was weighed, and the students made a note of specific items or trends that stood out. For example, nearly all businesses had some amount of plastic film waste in their trash cans at the end of the audit week.

In the process of gathering data, this project also provided a great opportunity to test and improve a framework for ongoing material and energy data collection at The Plant.


Each of the five businesses studied diverted at least 75% of solid material outputs from the landfill. Both Closed Loop Farms and Whiner Beer Company generate large amounts of organic material at the end of their production processes. This consists of spent microgreen trays (made up of coconut coir, microgreen seeds and partial stems, and compost) and spent grain, respectively. 100% of organic waste from both businesses is composted to create a nutrient-rich soil amendment for farms and gardens instead of being sent to a landfill. This brings the solid waste diversion rates for Closed Loop Farms and Whiner Beer Company to 99%.

UL, which offers landfill diversion claim validations for large companies worldwide, verifies “virtually zero waste” status for companies consistently diverting at least 98% of their solid waste from landfills. To have two of the five businesses studied during this project meet this standard is a great achievement, but there is always room for improvement.

The students identified the following concerns and opportunities:

  1. Opportunity to explore recycling options for variety of plastic waste (shrink wrap, vinyl packaging, straps, labels, gloves). These materials are used by most tenants in the building, and are currently going to a landfill.

  2. Difficult to find products packaging that is both food-safe and recyclable/compostable.

  3. Opportunity to explore shared purchasing and delivery for commonly used materials.

  4. Opportunity to capture waste heat and CO2 to circulate to indoor farms

  5. Opportunity to further study water use and explore ways to capture and reuse water within the building.

  6. Water use can only be accurately captured for businesses that are individually metered by a building owner.

  7. Furthermore, prospects for water reuse depend on:

  8. The quality of wastewater generated. For example, the quality of brewery wastewater makes it difficult to reuse directly. The water is a mix of effluent with extreme pH values and high biochemical oxygen demand, and requires more intensive treatment before it can be used for other non-potable uses.

  9. Infrastructure to treat, hold, and distribute water throughout a facility. For example, JustIce, a craft ice company at The Plant generates wastewater that can readily be used for non-potable uses (i.e. farm irrigation), but there is currently no infrastructure to support this reuse.

  10. For further reading about the challenges of dealing with water in a circular economy, check out the Ellen MacArthur Foundation’s Water and Circular Economy whitepaper .

What’s Next?

Guided by the results of this study, Plant Chicago is currently working with a select group of co-located businesses within The Plant to divert 100% of plastic film waste from their operations to a plastics recycling facility over the course of 2019. The baseline data and frameworks established by the Stuart School students allow us to start this project with a significant amount of background work already completed. Stay tuned on our blog for updates about plastic film diversion in 2019!


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