Interview Summary

This podcast is co-sponsored by the Recipes Food Waste Research Network Project, led by American University, and funded by the National Science Foundation (2115405).

Norbert: Welcome Callie and Celeste, it is a real pleasure to have you. Both Brenna and I are agricultural economists. You folks are engineers. So we are curious how did you come to be working on food waste and loss? Callie, let’s start with you first.

Callie: Thanks Norbert, and thanks so much for having me. I’ve been really fascinated by waste in general for a long time. Like what makes certain products and certain things valuable to people so that they’ll hang onto them and what makes us throw away other things. And for a long time I was studying sort of high tech waste like electronic waste, used lithium ion batteries, old solar panels or even plastics packaging. One of the things that I learned from that is that there’s so much resources and there’s so much value still contained in the things that we traditionally think of as waste. Whether it’s gold in the circuit boards of those old cell phones or it’s the chemical energy that can be converted into fuel energy contained in the carbon bonds of plastics. But, one of the challenges that I discovered in working with these different systems is that people don’t really connect to them very immediately or very viscerally. When we discard something like a phone it sort of goes away and we don’t really see what happens. However, I discovered that when people think about food, it’s extremely visceral. That was spinach that you bought at the grocery store with the best intention of eating, and it sort of hurts when you throw it away. It hurts your pocketbook as well as it makes you feel really guilty. So I got into food waste hoping to bring this perspective of value recovery and value retention to the food system. But, doing so in such a way that really connects to people. So looking for technologies and user-friendly solutions where we can first of all try to keep food from being discarded. But then if it is inevitably discarded how can we use best engineering and technology practices to actually recover the energy, the water, the nutrients that are contained inside instead of sending those to landfill.

Norbert: You really are playing off the old idea of one man’s or one person’s trash is another person’s treasures. I appreciate that. And you’re right, food does have this deep connection to us from a lot of different perspectives we don’t like and we have been taught over and over again not to waste food. So I do appreciate how you were able to take what you’ve learned in other spaces to the food space. So thank you for coming into this conversation. I’d like to turn this over to Celeste. Your work began in areas around food access and now exploring food waste and loss. What interests you about this societal challenge?

Celeste: So I really fell into the field of food waste. As you know, my background is in transportation and I’ve always been really interested in the societal impacts of transportation. A lot of my work focuses on equity and accessibility metrics related to transportation. I was working in the food access space before coming into food waste. I kind of first got interested in food access actually from a student of mine who for their senior project wanted to know which food insecurity or food desert metrics should they be looking at for their senior project. We started looking at how different parts of Baltimore indicated different areas of food insecurity. So that’s really how I got interested into food. What has been the most interesting about food waste is that transportation is important to all aspects of the food supply chain and just the scale of the problems can be so different. We can think on a worldwide scale, a national scale regional and household level. For me household level has always been I think the most interesting when it comes to food waste questions. I’ve always been very interested in choice in how people make choices whether it be transportation or food purchasing habits and also how those two work together.

Norbert: Thank you Celeste for that. And I would say the first time I thought about transportation and wasted food or food loss was the challenge that food manufacturers have once a product, especially something like a fresh vegetable or fruit, leaves the farm. If it starts to go bad what are some alternatives to manage that potential loss as the product that’s being transported from the farm to the packing house and from the packing house to a food manufacturer or retailer. And that there are real challenges of actually redirecting product once it leaves the farm. It’s really exciting to hear how you think about that. Not from the farm gate necessarily but also to the final consumer. So thank you for the work that you’re doing.

Brenna: Celeste, if we can continue with you the work you have done focuses a lot on transportation and waste management. Can you tell us more about how your research has informed the ways that we need to think differently about wasted food as a household or a farming problem?

Celeste: Sure, I’ll speak about it mostly from the household level. One of the things that first came out of my previous work is that everybody values having choice and agency in their food purchasing. I don’t think that we often model those choices when we’re doing transportation modeling for example. I think that’s still important when it comes to food waste. In my previous work I talked with a lot of people during my focus groups about how they’re making the decision of what stores to go to, how often and why. What we found were that households were balancing tough decisions when it comes to limited budget, quality of food not being equal everywhere, which really gets at some of the supply chain issues and making difficult trade offs between how often to shop versus how much they’re able to purchase. I think some of those lessons learned translate to food waste particularly when we talk about rescuing food how we go about rescuing food for example do we just provide boxes where people don’t have a say in what those boxes are? Are we matching wasted food to the demand and the needs of people? So I think a lot of the lessons learned can translate well into the food waste space as well.

Brenna: I really appreciate those perspectives, Celeste. And appreciate that agency discussion as well. Norbert and I actually have a recently published paper on the tradeoffs households make between the frequency of grocery shopping and the food waste that they incur. People definitely have pretty strong preferences for the amount of transportation they may put in going to and from the store in a given time period. Callie, shifting to you is there anything you want to add related to this topic?

Callie: One of the things that Celeste pointed to is the complexity of this challenge. While we may see quite a large percentage of food waste happening at the household level, that waste is really magnified once we look all the way up the supply chain. And transportation plays a key role at every step of the process. Not only in the transportation of food to the downstream markets, but then the collection the transportation, the aggregation, and all of the choices that then these stakeholders make at a broader scale. So say a grocery store or a restaurant decides to engage in food waste diversion and recycling behavior then the transportation becomes a key part of that. Food is heavy, wet and kind of stinky. So it’s a little bit of a unique challenge for transportation in that we both want to pick it up and transport it regularly to a place where it can be recycled but that transportation can be really expensive. So this is another challenge where it speaks to these broader questions about infrastructure because then you have to start deciding where can I put locations to site recycling food waste to energy locations? How do I actually collect the food waste from what places am I going around in my truck and picking it up? Where do I take it and then how do I use the products that come out of that? Because once you have taken food waste and say you’ve put it through a composting process, and you have the solid compost that comes out. Or perhaps you put it in an anaerobic digester and you have bioenergy in the form of natural gas or electricity that comes out, all of those products then have to be transported back to places where they can be used. So transportation really does infuse the entire system even if sometimes it means we’re transporting things other than food itself.

Brenna: That’s a really important point and it does add up in between each stages of supply chain and then sometimes back again, once we have these new products and then transforming them and moving them back to where they can be used again. Celeste, if we can continue with you, what are some of the transportation challenges that contribute to wasted food?

Celeste: One of the things we deal with in transportation is just it’s a uncertain science, there’s always some built in uncertainty with transportation and when we’re talking about items that are perishable like fresh food, that is what results in a lot of food waste because they are buffering for that uncertainty and travel time. One of the big challenges is how do we reduce uncertainty and have more reliability in our transportation system? That’s becoming more challenging as land use changes. We’re seeing farming being more consolidated food is being produced further from where people live as well as just our cities were decentralizing which makes transportation even more difficult. Some of the biggest challenges related to transportation really linked to changes in land use patterns as well as the production of food and how we can kind of bridge those gaps together with transportation. In the near term rising gas prices is definitely a challenge and it’ll be interesting to see what impact that has on the food supply chain and to customers as well.

Brenna: That is a really important point. I can imagine where some efforts maybe to recover and recycle foods may be stagnated if transportation costs are too high. Thank you so much for that perspective Celeste

Norbert: Hearing this conversation makes me think of something you said earlier, Callie. And it’s this idea that previously you’ve worked on how to manage waste of science and technology products. There might be gold the circuit of a cell phone or something. But, when you talked about food waste you talked about heavy wet products and ultimately I thought of products that are of relative low value and given that there are rising costs in terms of transportation related to fuel costs how do we balance this? How do we get this relatively low value product on a per unit basis given that there is these high costs associated with transporting them? What do we need to make that equation work out?

Callie: That’s a great question, Norbert. This is the perfect opportunity to bring in what we call life cycle thinking. So not just looking at the end of the pipe or at the last part of the problem when this waste is inevitably generated, even if we’ve put in place efforts to try to prevent or reduce it or divert it upstream, some waste will inevitably result. It’s not just about the cost and benefits of that process of managing it but really thinking systemically over the whole supply chain. The food that we’re talking about ultimately was produced in such a way that consumes significant amounts of energy, water, and nutrients. We pump a lot of electricity, a lot of fossil fuels, a lot of land, nitrogen, phosphorus and water into the production of food. So all of that is opportunity for us to recover that value at the end of life. The food itself contains much of those resources. It contains a significant amount of carbon, nitrogen, and phosphorus. These are things that we might normally have to obtain from more environmentally intensive process if we’re extracting them from nature transforming them into a form that we need for agriculture. And so then when we think about what would happen otherwise to the food if then we move downstream, if we aren’t recovering the food at end of life or doing some other activity to reduce or donate surplus food before it becomes waste then we also have this huge cost of the landfill. Depending on where you live in the United States the cost of land filling products varies significantly. In some places it’s pretty expensive and that’s because landfill space is scarce. And it’s also in recognition of the fact that there’s a huge climate cost of landfilling, when the food enters a landfill environment where it’s anaerobic or in other words oxygen free. It degrades in such a way to where methane is the primary product and if that methane is not captured at the landfill that has a climate impact 25 to 30 times more than carbon dioxide. So we can also think about attaching a cost or even a social cost of the carbon impacts that come from the landfill.

So when you look at this systemically you can think about food waste as a real value recovery and value retention process, in such a way that those costs associated with making it happen are worth it. When you look at the life cycle cost of the food system you can think about using this process to recover some of those initial embedded impacts and the initial embedded carbon, water and nutrients in the food as well as to prevent the downstream cost of unavoidable and unconstrained climate impacts from land filling food waste. But I would also say that for many companies and for many actors in this space they also see a value in food waste recovery. Many households are deciding to try composting for themselves or to work with a community compostor because they value the ability to produce that compost and use it in some way at home. Similarly, businesses are looking at some opportunities for food waste diversion that actually save them money. It may end up actually being cheaper to divert this material and use it in such a beneficial way to recover some value from it than to pay to have it hauled to this landfill instead.

One of the really cool areas that we’re looking at is one in which we can think about decentralized solutions in parallel with centralized solutions. Our conventional waste management model has been to collect material within a relatively constrained area and then haul it to some location where it can be processed or landfilled afterwards. There are all kinds of new food waste recovery technologies that are emerging where they can actually be put in place at the point where the food waste is being generated. So this might be a small-scale digester, dehydrator or compostor being embedded right there at the restaurant or at the point at which the waste is generated. Now those can be still very cost sensitive for some businesses but there’s some cases when they actually make more sense economically than alternatives.

Norbert: Thank you so much for that. That really adds some clarity to this issue of how do we valorize food waste. And what I’ve heard from you is that one of the ways of thinking about this is it’s the avoidance of the cost associated with processing or throwing away that food that there can be significant effects on society, on the climate by having this product go into a landfill. We can avoid some of that and we can actually capture some value that there are different actors along the supply chain or different supply chains that could benefit from this. So thank you for that, that’s really helpful. Along this line I’m interested to hear your thoughts Callie on other ways to improve the transportation infrastructure or the management of food waste that can help us prevent this possible wasted food.

Callie: When we think about minimizing and managing wasted food we really want to take this full circular economy perspective. Circular economy focuses on recovering and retaining value from products rather than thinking about it as waste management. So it’s a real change in paradigm first and foremost. And within this circular economy framework we might first be looking at minimizing waste like designing waste out of the system by some of the things that Celeste is shared about ensuring that we actually get food to people who are going to consume it in ways that they want to, in a way that works for their choices. Then, if there’s some excess food or surplus food, food that’s in the wrong place at the wrong time, then we can think about diverting that through rescue and recovery operations. Transportation clearly plays an important role there because again, you have that sort of narrow time window to get food from one point to another where it can be used effectively. Then finally, in terms of closing the resource loop by this valorization process there are a lot of open questions there that I don’t think we completely have the answer to. This again speaks to the importance of a systems perspective. So first and foremost, determining what the optimal strategies are for collecting waste. If I’m a food waste collection business what company do I start with? Where do I pick up waste first? How do I optimize the training of the people who are employed and engaged in this activity? Because if food is not separated effectively at a source and contamination like plastic packaging or other materials in the food waste stream that can really throw a wrench downstream when we try to recycle it. So there’s some questions there about optimal methods for separation, segregation and collection of the food waste. And, there’s all these open questions about the siting and the scale of the technologies we would use to actually treat it.

I mentioned earlier this question between small scale decentralized and large scale centralized systems. Another thing to layer on that is then the optimization of the markets and the transportation and the siting of the product uses. So one of the most common and promising methods that we’re looking out for food waste recycling from commercial not necessarily households but the upstream suppliers is anaerobic digestion. Because in this case we’re taking that anaerobic environment with oxygen free environment where the food degrades into methane, methane’s the primary constituent of the natural gas we use for heating and driving and other things in our energy system. We can certainly take that energy and put it back into use if the food waste recycling facility is located near a transmission grid or near a pipeline where the compressed natural gas can be injected. But on the flip side, there’s other products that come out of that, like a liquid digestate stream, which has some of those nitrogen and phosphorous nutrients still there. Now this could be land applied on farm fields but it is also really expensive to collect this liquid, transport it and then apply it into different areas. You have to be cognizant of the ecological impacts of applying this to land, especially if you are near freshwater resources that may already be vulnerable to agricultural pollution. I don’t know that there’s really a clear pathway of a one size fits all recipe for setting out these food waste ecosystems. But, I think there are a lot of open questions about the best way to optimize this system in different regions and parts of the country because everywhere has different sort of local infrastructure, ecological resources and transportation available. That’s one of the most exciting parts of researching this is, is trying to figure out the right solution at the right place.

Norbert: Wow, thank you for that. That’s really helpful. I’m grateful in particular for this idea of reframing our thoughts about waste management and how to think about that differently changes the way we actually approach these issues. We’re at the end of our time but I wanted to raise this question to Celeste because Callie I think you’ve addressed this to some degree, but feel free to jump in. How do we want to make sure we include the environmental impact in the work that we are doing in reframing waste management? Are there some important things that have been left out? Should we reconsider? I would love to hear your thoughts on this.

Celeste: When it comes to food waste, one of the things that really is important is that it is an interdisciplinary field. Often I find as we talk about the role of transportation in food waste is that everybody recognizes that it’s an important component of food waste but often it’s a separate conversation. So listening to Callie in particular, she highlighted the importance of making sure that transportation is being included kind of as a decision variable in our models. That transportation is not just an afterthought as one of the costs associated with transporting food. When we really embed transportation into the decisions that we are making related to food waste it naturally has a positive impact on the environment as well. One thing that I am curious about is the role of new transportation technologies in the future. Our field is evolving quite rapidly with autonomous and connected vehicles drone deliveries and things like that. In the future there will need to be research to look at what new technologies can do in the field of food waste.