Audio: Products, Plastics, Putrefaction, and Power

The majority of urban trash is plastic or biodegradable. What is the best way to manage these materials? Businesses and environmentalists are battling it out right now.

Products, Plastics, Putrefaction, and Power

Trash Talk Public Lecture by Samantha MacBride

Adjunct Assistant Professor of International and Public Affairs, Columbia University School of International and Public Affairs

We tend to think about “trash” as all one thing, but trash is composed of sets of materials whose molecular properties, economic status, and cultural meaning are quite distinct. This illustrated talk examines two sets of materials in trash – (1) the wide variety of products known as “plastics” and (2) biodegradables: including food scraps, yard trimmings, and other things that rot.

Coalitions of businesses see a profitable future converting plastics and organics into chemicals and energy. But environmental movements argue to phase out plastics and compost biodegradables. The rift in policy attention, business approach, and social imagination between the two opposing viewpoints is great, and sheds light on how society grapples with materials we discard, and how we might manage materials in a more a more just and sustainable way in the future.

Recorded December 1, 2011



Welcome to the last in the Peabody''s series of fall lectures. I'm Pamela Gerardi, IDirector for External Relations for the Peabody Museum. We are going to be continuing our series in Trash Talk next semester. And we've got a really interesting lineup of people talking about recycling at Harvard, ocean plastics and even garbage as a result of natural disasters. Our spring calendar should be up on our website pretty shortly in the next week or so. So I encourage you to take a look at it. Tonight's speaker is Samantha MacBride, Adjunct Professor at the School of International and Public Affairs at Columbia, and Deputy Director of the Bureau of Waste Prevention, Reuse and Recycling at the Department of Sanitation in New York City. Professor MacBride holds a PhD in sociology and an MPA in Environmental Policy and Planning from New York University. She specializes in urban environmental politics, cold policy and solid waste management. Solid waste management, excuse me. Her current research focuses on the contested politics of municipal organic waste management in the US and Canada. That is, how social movements, business sectors, and the state understand and advocate for landfill gas recovery, industrial scale composting, and conversion technologies. She's the author of Recycling Reconsidered: The Present  Failure and Future Promise of Recycling in the United States, a volume to be issued by the MIT Press later this year. Yeah, just a couple of weeks, in just a couple of weeks. Tonight, she's going to be speaking to us about products, plastics, putrefaction and power, rethinking how we manage materials to achieve just sustainability. Please join me in welcoming Professor MacBride.

Thanks very much. Let me just get up my actual PowerPoint for tonight and can start talking. I'm going to be talking about exactly what my research interest is in organic and other carbon-bearing wastes and policies for doing useful things with them. Can everyone hear me? Okay? Okay. So, for me, understanding what we should or can or have, or may sometime in the future do with the waste that we produce in cities, municipal solid waste? is a question of what kind of society do we want to live in? What kinds of employment what kinds of enjoyment? How do we want to organize things like our health, our access to resources, jobs, wealth? How do we want to distribute these things? How can things be most fair? How can everyone have the same right to a clean environment, right to a meaningful job, to not be exploited in their job and also to have clean and affordable energy. And the right now I'm going to talk about a division that is active within a small segment of society that focuses on waste issues that takes two very divergent perspectives on what to do with our wastes. One perspective, as I'll explain, sees promising future in turning mixed wastes as shown in this rather disgusting picture of plastic and food waste into energy. And another different perspective, sees a future sustainability that, among other things, depends on separating out materials. This is a photo I took at the New York site of Occupy Wall Street before it was closed down. 

So tonight, I'm going to talk about what is in our municipal waste, what we are doing with it, what we can do with it in terms of technology and policy, what the risks and rewards are of these alternatives. And there are a couple of things that I want to make sure that you take away from this lecture. One is that most of our trash contains carbon. And this is very important from the standpoint of global warming, obviously, from the standpoint of energy security in the United States, as well as our connection with life and living things that are all based on carbon. The second is that plastics in their complexity are a big, messy, difficult problem and I'm sure after this talk, there going to be a lot more questions about plastics and plastics recycling, and I'd be glad to get into them. It's not a simple subject and it has no simple answers. I am going to talk about the literature, and engineering, and epidemiology, on technology, and risk around different ways of handling waste. But I'm only going to lightly touch on it. Because what I bring to the table is more a social science perspective, I'd be glad to direct people to the literature that I've consulted. And I welcome disagreements about what I'm going to say about technology and risk from an engineering standpoint. I'm also going to be talking about the history of the environmental justice movement a little bit. But I'm not really going to be focusing on the past as much as what I personally can bring to the table to inject something new into this discussion, and that is to share detailed information about the composition of municipal waste, and how this composition relates to a very broad conception of sustainability in the full sense of the word. So shown here is a bag of mixed food waste and plastics, some dirty diapers, a bag of fall leaves in a plastic bag, and the leftovers from some school lunches on styrofoam trays. What all of these materials have in common is that they contain carbon. And similarly, the textiles that go into our trash the paper that isn't recycled, wood wastes, rubber, both synthetic and natural leather. These are all fractions of ways to contain carbon.

And in fact, carbon bearing materials make up 85% of all municipal waste. This data is the most recent from the US EPA's characterization of waste in the United States. If we did a characterization of Boston it would look very similar to this although it might have a little bit less yard trimmings because there isn't as much outdoor space, but this composition profile is typical of cities and towns across the United States. 64% of all discards are what are called biogenic, meaning, they are made from living things plants and a little bit of animals. Another 12% are purely synthetic polymers that have been put together by chemistry. And these are by and large plastics, but they also include synthetic synthetic textiles like polyester and things like that. And then there are materials such as textiles and rubber that may be synthetic or biogenic. In total, these add up to 85% of everything that Americans throw away. Now, the biogenic fractions of our waste have in common the fact that because they came from life, they came from plant and animal matter, they rot. And on one hand that makes garbage have the stigma that it does. rotting decay, not only carries odors, which are very potent culturally, but also conveys a sense of death and disgust. And when you really think about it, the really objectionable parts of garbage are the biogenic parts. If you take them out you don't find garbage to be disgusting at all and, and furthermore, the mixing of the biogenic, the rotting, putrefying fractions of garbage with other substances, the smearing of, for example, food waste all over plastic trays, extends the disgust of garbage and it's something that we want to get rid of get out of our houses very quickly. On the other hand, the capacity to putrefy also leads to something wonderful and something beautiful under natural conditions and that is decomposition and ultimately, the resolution of all of this material into something incredibly useful, and, and nurturing which is compost, which is soil. This is not the case at all with synthetics. In fact, quite the opposite. Synthetics are marked by their permanence. The permanence of plastics causes problems at a variety of scales, from the molecular level with the ingestion of certain plastic additives or types of plastics, to the larger scale with the ingestion of pieces of plastic by wildlife, which is a serious ecological problem to the macroscale. And there will be someone talking about this later in the series, the accumulated plastics in ocean deposits which are interfering with ecosystems on a large level. But what both biogenic and synthetic carbon-bearing waste do share with their carbon atom is their capacity to create energy under conditions of combustion. So you put together a hydrocarbon which is going to be synthetic or or biogenic with oxygen. And what will you get? You'll get energy in the form of fire or something more advanced than that, a little bit of water and unfortunately, co2. And that process is what we're dealing with is climate change when it's applied to fossil fuels. So with this understanding of the role of carbon and biogenic and synthetic fractions of solid waste, the next question is, what should we do with this material that we are generating in cities? What are we doing with it now? And what could we do with it differently in the future? Well, if we go back to our pie chart, and resolve it back into the black bag, it comes out to 250 million tons of discarded materials throughout the United States. And over 50% of that is now going to landfills. Another 12% is being combusted to create energy, recycling is getting a little over a quarter of it and composting quite a bit less.

The role of recycling and composting which are shown in the top portions of this time series graph have grown over time, since around 1960, when problems of municipal waste started to be understood in ecological terms as well as operational ones. This graph also shows that combustion with energy recovery started to take off around 1980 but then stabilized around the 1990s in terms of growth and the reason for that was very specifically the power of social movements opposing the opening and siting of new incinerators. And today there are 100 give or so, incinerators or waste to energy facilities in the country with very little hope of new ones opening up within the industry. Now, what are these options that are receiving our disposed waste? Well, first of all, there are landfills, which I mentioned are taking over half of our waste. There are about 2400 of them operating recently closed in the US. Most are owned and operated by private corporations that may also hold collection contracts with municipalities and may also provide recycling services to cities and towns. They are far better today, sanitary landfills, than they were up through the 1950s when open dumping prevailed as a way of landfilling. They have extensive controls and liners and monitoring systems. They're regulated under federal law, as well as state permits. But they do entail certain risks. And the risks in the near term and long term—I'll just summarize them quickly—involve the water that precipitates out of material deposited into a landfill which is called leaching, which needs to be treated before it is released. And the treatment entail in turn, means removal of contaminants, heavy metals and organics that have to be disposed of elsewhere, as well as airborne emissions, primarily methane, which is a very potent greenhouse gas and co2 as well, which result from the decomposition under anaerobic conditions of our biogenic wastes in the landfills, as well as smaller quantities of air toxics that may be released in different quantities in different times from landfills. Now, a little over 500 of landfills in the United States right now have what are called gas to energy collection systems, which are essentially methods of collecting a lot of the emissions, the methane-rich emissions from landfills and routing them akin to natural gas to energy production, right there, sometimes right there on the landfill or very nearby, producing electricity. Now these systems are very beneficial in that they do provide a little bit of power and they also diminish emissions, but they don't entirely remove them. In fact, landfill gas collection systems collect between 60 and 70%, depending on who you're talking to, other emissions. There are such things as fugitive emissions which are not captured in the piping systems, which are still being released in in significant quantities. Another option which is operating for a minority of our waste in the United States, but as much more prevalent in Europe and Japan, is the combustion of combined municipal solid waste to produce energy in a waste to energy or mass burn facility. And these facilities are essentially power plants that are fueled by deliveries of mixed municipal solid waste, which is converted to electricity and or steam with the emissions from the combustion going through stages of cleaning, and scrubbing and participant participation, and other technological methods to capture and remove the toxins and contaminants that result from combustion. And these facilities can be quite clean when they run very well. And in fact, this picture up here is of a famous waste to energy plant is right in the middle of Vienna, Austria.

However, they do still do entail risks risks if they break down-risks involved with the disposal of the ash residue that is left over from combustion and risks from disposal of the the scrubbers and other cleaning technologies for the emissions. Now, the commonalities to landfills and waste to energy facilities that are operating in the United States include that they can accept all types of waste. They can accept biogenic and synthetic wastes, they can also take in glass and metal, no problem and spit them out at the end. They are convenient in the sense that they don't require residents to do anything special, you put out your black bag of garbage that goes in the back of a truck. It goes to one of these facilities, it's dumped, and it's no muss, no fuss. It's also more efficient for municipalities to send out trucks to collect material that hasn't been separated because everything goes in the back of one truck and you have economies of scale. But no one really thinks that landfilling, most of our wastes in the United States is a good way of dealing with it anymore. You'd be hard pressed to find most people arguing for this. There are alternatives, there have been alternatives for quite some time. And they're being pursued as well. The major alternative is recycling, recycling as probably all of you know it. And what I've shown here is from the City of Cambridge is recycling regulations or flyer, most recycling it that we think of in the common term of the word in the United States, is done through what's called source-separated commingled curbside collection. Probably all of you do this, right, you separate out your paper, your cans, your bottles, some of your plastics, and you put it in one receptacle, or one clear bag, and that is collected separately from your trash. Is there anyone here who doesn't have that kind of system? Okay, and I assume we have sort of a range of communities represented. In isome cases, you will be limited in terms of the plastics that you put in, for example, in my city, New York City, to only bottles and jugs. In other places, you may be allowed to put a wider range of plastics in we're asked to in Cambridge, you're asked to put stiff plastic containers, and large plastics, as in broken toys and laundry baskets, in almost every municipality is going to be a little different. And it's going to vary across the country for reasons I'll explain. But by and large, there are prohibited plastics from going in there as well. In the case of Cambridge, we've got no plastic bags and no styrofoam, both of which are pretty significant fractions of plastics. If people are like anyone else I've talked to throughout the years, they're not really understanding why they're these distinctions made. And that's one of the things I'm going to be talking about tonight, is going to get long and complicated and detailed, but it's very important to understand with regard to these large questions of what kind of society we want to live in. Now, when the mixed collections of recycling are taken away in a truck, they are taken to what's called a materials recovery facility. I apologize for the blurriness of this and I'll sort of orally walk you through the steps that this kind of plant entails. But essentially, the mixed load of recyclable paper, metal, glass and plastic arrives at one of these facilities and goes through a series of automatic and mechanical steps to separate each type of recyclable from another because that is the key to marketing them and putting them back into production as a secondary material or was, which is the term for substitute for raw material. And this is done for some materials relatively easily. For metals, it's done very easily because magnets pull out the metals and eddy currents, electrical currents, can pull out the aluminum while there are series of shaking screens of different sizes and blowers that separate the paper from the heavier fractions. Glass, which is generally very broken by the time it gets to recycling facility, can be sifted out.

But the most complicated step in this process of disentangling recycling is how to separate the different types of plastics from one another. There are nowadays such things as optical sorters, which are laser technology that can recognize certain types of plastic. And when they hit this piece of plastic, they will send a little shoot of air, which will send it springing off into a particular basket or hopper. But these technologies are very expensive, and they can really at this point only be calibrated to one type of plastic or another. And I'll be going into this in more detail as I go on. What happens in the sorting process as a result of the limitations on technology for plastic sorting, is that there's a great deal of manual sorting that also goes on with laborers standing over conveyor belts of mixed recycling, knowing what to look for in terms of plastic and pulling it out as it goes by. Now, there are alternative methods to recycling that entail very different forms of collection. And probably the best known of these are bottle bills, which you fortunately have here in Massachusetts. This is a very different approach to how to bring recycling in to have it processed, it's going to be automatically sorted ahead of time because the whole method is not to collect it in the back of a packer truck with a lot of other stuff. It is to provide a very modest incentive for either the consumer or an itinerant entrepreneurs in this case, to bring it back to the point of purchase, and the line in the bottom here in black shows the average recycling rate for beverage containers throughout the US in most states in in 40 states, there are no bottle bills. The much higher rates are in states with bottle bills and the very highest nearly 100% return rate is in Michigan, where they take in the very drastic step of increasing the deposit from five to 10 cents per container. Another great example of a different model for recycling is auto batteries. They have the highest by far recycling rate of any material in our trash, 98%. Almost every state in the United States has either some form of deposit or other mandatory requirement to turn in your auto battery, rather than put it in the trash and many of them have very severe penalties for putting in trash due to the acute toxicity of auto batteries. Composting is the other side of the coin for biogenic wastes. And it is another method that involves source separation and ask the consumer to set aside wastes before they're collected and to keep them separate. And in Cambridge, you have yard waste composting and it looks like you're required to put it in paper bags. Has anyone participated in that here in paper put putting your yard waste and paper bags. Yeah.

Okay, so barrels either way, that's good because you're bypassing the plastic and what you've got collected here is totally compostable in many other communities. You can put it on plastic bags which is going to add another step of processing at the compost site. In about 90 cities and towns throughout the United States, notably San Francisco and Seattle, you also have the opportunity to source separate your food waste and your soil paper which makes up a lot of the biogenic fractions of the trash for source-separated collection along with your yard waste, and we're moving to a composting facility. And at a composting facility, a traditional style one, composting will may be taking place outdoors or indoors, but it's going to be taking place in the presence of oxygen and what's called aerobic decomposition that's going to yield a very rich, nutrient rich soil amendment compost, but unfortunately also is going to emit some co2 through natural processes of biological decomposition.

Yes, great. And your compost barrel is also emitting co2. Yeah. Yes, I'm all for that. Okay. So with these systems in place, how much is actually getting recycled or as we say in the business diverted to recycling? Well, PLAs excuse me, paper is a success story throughout the United States. 63% of all recyclable paper actually does get put in the recycling bin and goes off to be recycled. Yes, it includes cardboard, I have to actually ask you, I have so much information to get through. If we could hold questions to the end. I greatly appreciate it. Thanks. metals and glass have decent rates of recycling at least in the double digits, plastics 8%. So why is this why this low, low amount? Well, the answer does not really have to do with people's failure to recycle because if that were the case, you wouldn't see the higher rates for the other materials. The problem with plastics recycling has to do with its heterogeneity. A lot of you may be familiar with the one through seven symbols that are on plastic containers. These symbols which were devised and applied by the plastics industry itself, only begin to tell the story of the complexity of different types of plastic. First of all, number seven is a casual category that it needs that reflects untold numbers of different types of plastic second, and this is something that is very difficult to convey to the general public. Even if something better is the same numerical code, the way that it has been extruded to make a product may preclude its recycling with another. So for example, a number one which is high density—or excuse me, a number two high density polyethylene bottle and then number two high density polyethylene tub cannot be combined in the recycling process, they have to be sorted separately and kept separately and marketed separately and melted down or pelletized separately, because they were produced with different melting points in different viscosity. And this complexity gets multiplied throughout the entire chain of different types of plastics, forming different types of products durables, disposable plateware, film what are called film plastics, flexible plastic, semi flexible plastics, tubs and trays, bottles, toys, etc. Now, what you have is an incredible variety of materials that have to be kept apart from each other in order to find economic value, they have to be sorted, which takes labor, and they then have to find markets to be stockpiled and ready for market. And it is can only be described as in general with a few exceptions, which I'll explain in a second, and mess, a mess that is concomitant with the range of different types of plastics that pervade our lives today. Now, this is a graph from the EPA that divide divides plastics into over 40 categories, and that's only really scratching the surface, because a lot of these categories are number seven, which could be additional types of plastics. It shows in this graph, the tonnage of each material that's generated, and in only about five cases do we see a significant quantity of recycling which is the blue part of the line going on. What are these five types of plastic that seemed to be recycled more successfully? They are number one and two bottles. Number two tubs and trays, number four, which stands for low density polyethylene wraps and sacks and bags. And number five, a mysterious—excuse me, number seven, a mysterious category of other durables, not containers, but durables.

The number one and two materials by and large do come from residential sources. The number for plastics may come from programs, and I'm not sure if you have them here in Massachusetts, where you bring your plastic bag back to the shop to recycle it. You may wonder why can't I put it in my recycling bin? Again, it gets to this question of it having to be sorted out and having more economic value when it's kept all one thing. However, a lot of this material that get does get recycled is from businesses and is things like their shrink wrap on on pallets and other kinds of delivery products that are by their very nature not going to be mixed with other types of garbage. And finally, a large fraction of this mysterious number seven is actually the housing and the casing on our friends, the auto batteries that have a very high rate of return. Now I understand that these are confusing statistics. And if people want to talk about them in more detail, learn about them in in where they can get the stats from the EPA, or other corroborating stats, I'd be more than happy to get into this. But let me just summarize it this way. 

There are 31 million tons of heterogeneous plastics generated in the United States every year. Only 2.3 million of these make their way to recycling. And out of them, 2.2 million are these resins that I've discussed and leaving everything else unrecycled. And what this means is, this is significant, not just from the standpoint of failure to recycle, it's significant because number one, the labor that is involved in teasing apart, mixed collections of plastics is particularly hard, low paid labor, it's not the kind of job that we really want to associate with sustainability. It's a frantic job of trying to pull out number one into bottles, and jugs from a whole mess of other products. And I've seen it firsthand, I would not wish this job on anyone. Furthermore, because there's a lot of pressure on municipalities to collect more than number one and number two containers, a lot of the residual additional containers and number three through sevens either get landfill-disposed of after the recycling process, after they go through the recycling plant, or they get sent abroad where wages and labor conditions are different. And it makes economic sense to sort them out methodically by hand as shown in this picture. In fact, a great deal of the plastics that don't have markets here in the United States are recycled in that way. And this is a very big and very important story that I think people need to be more aware of, because calling for more plastic recycling in your curbside program can inadvertently lead to more of this. To get to our other carbon-bearing wastes, how much of these are getting recycled and removed from disposal? Well, it's pretty low rates for textiles, for rubber, for wood. As you can see in these small little fractions that are coming out of the pie not much, 3% of food wastes are currently being collected under the source-separated programs that I've told you about through United States. Yard waste, on the other hand, are quite a success story. About half of them are being collected separately for composting driven, largely, although not wholly, by bans that states are passing on disposing of yard waste in landfills, as they have here in Massachusetts.

But after all of this recycling and composting, what is left is about 180 million tons a year of material that needs to be handled in some way. And this material is even richer in synthetic carbon-bearing materials than it was before the recycling take took place. It's still about 84% carbon-bearing, but now it has proportionally more plastic sticks in it than before the recycling. So what what can we do with this material? Well, I mean clearly you can see, more recycling and more composting. But there are a lot of other alternatives that are being discussed that look at new and different ways some of which are iterative iterations of methods that have existed for a long time of making something useful with with all of this carbon varying waste energy materials, or both. Now, one of the most exciting from a technological and economic standpoint, options involves can not combustion, but the conversion of carbon-bearing waste to energy under much higher temperatures than in an incinerator with much less or no oxygen involved in the process and therefore, fewer emissions and fewer toxic residuals due to the very high temperatures involved. And as, as well as more efficient extraction of energy from the garbage feedstock. These technologies which are called thermal conversion technologies fall under the headings of pyrolysis and gasification. I'm not going to get again get into the details of how these these processes work from an engineering standpoint, but I can point you to, to a lot of literature on that subject. They are, they do have the benefits I'm talking about. On the other hand, they are pretty much unproven here or anywhere else in the world with regard to municipal solid waste and therefore, their safety is more of theoretical than empirical basis. And they are very, very expensive. They require massive amounts of investment in facilities up front in order to envision them working to handle disposed wastes. Another option that is more in use with agricultural wastes today is called anaerobic digestion, which is essentially composting in a drum under anaerobic conditions so that the micro organisms are releasing bio gas which is is very heavy, and methane, kind of similar to the landfill gas. That gas is captured and collected rather than being allowed to just dissipate as it does from traditional composting. This method yields a good compost product. It is much safer because it takes place under low, low temperature conditions, much safer than conventional incineration or landfilling. However, it can only accept biogenic waste. If you put plastics into an anaerobic digester, you're going to get plastics at the end. Other approaches take a very different view of how we should deal with these fractions of our waste. I've talked about bottle bills, there are a host of legislative initiatives being battled out throughout the United States that seek to diminish plastics, and the complexity of plastics and certain types of plastics, styrofoam being one of them, through either bans or fees or levies or other legislative and regulatory initiatives that make it more expensive for producers and consumers to go through the ritual of using all of this plastic. There are still other options which have been around for a long time and for which there is renewed interest from an ecological standpoint, are local community-based ventures that are particularly suitable to wood and textiles and that reuse and remake these materials locally using local labor into things that people can use.

So with this range of options that we might think about with what to do with our waste on the table, what are the risks and the rewards? Well, for venture capital and for the waste management industry, there are there's a great deal of excitement right now. This is what I wanted to talk to you about because this is going on at the level of the waste business, but it's not really generally discussed in in public and that is that with the increased sensitivity to climate change, carbon, the possibility of carbon trading, the need for renewable energy In the United States and energy independence. There is a sort of a renaissance in opportunities for conversion of carbon-bearing wastes into energy using these new technologies of pyrolysis and gasification. There's great profit that's seen in this and also great risks on the part of these industries. And the risks that we're talking about are not risks from pollution. For these industries, they're financial risks. As I mentioned, these these types of facilities and even conventional waste to energy facilities require a great deal of upfront investment in building infrastructure as opposed to landfills which are pretty cheap to build. They are under heavy opposition and definitely will be. And that makes the investment horizon even more risk , sorry. And firms are, are right now grappling with how they can minimize their risk manage their risk, and there are a number of ways of doing this. One is to integrate and waste management, which Waste Management Inc, which is the largest private waste management company in the United States, is right now acquiring a portfolio of small startup companies that do everything from conventional composting to anaerobic digestion, to pyralysis to conversion, excuse me to gasification to be able to offer municipalities a menu of options of what to do with their carbon-bearing wastes in the future—choosing which to promote and build at any time based on what's most profitable, and what the municipality can afford. There are other ways that these firms can mitigate their risk. And one of the major ways that they all agree on is that they need a supply of organic rich material that they can depend on, if they're going to invest the millions of dollars to build these facilities in the first place. What this means is they if we have policies in the future to increase recycling, or diminished consumption through regulation, that is going to be antithetical to the business model of the conversion industry. And this is something that is recognized and widely discussed in this business sector. The critical factor is, as one industry spokesperson said, it is to have a long term supply of feedstock. And one thing that municipalities can do is enter into long term contracts where they agree to do this. Another form of risk mitigation is to have states redefine what is diversion, what is resource recovery, what is not disposal, what is sort of a positive, sustainable thing to do with waste, to include conversion to energy, in addition to recycling and composting. And therefore, if a state has, for example, a mandate that they have to reduce disposal by a certain fraction, anything that goes to conversion to energy can be counted in that mandate. And finally, there are a spate of incentive policies tied to renew promoting renewable energy that are existing or considered that offer tax breaks, grants and other types of incentives to the conversion industry, to build facilities and get into the business.

And if all goes well, this is a little hard to read. But this schematic shows all of the things that can be made out of the synthetic gas that results from gasification which is one of the conversion technologies. It can go to power power plants, it can be converted to fuel that can substitute for fractions of gasoline. And furthermore, through catalytic reactions the synthetic gas from conversion from gasification can also become everything from alcohol to olefins to waxes and ammonia and a range of industrial chemicals that are part of the way that we produce goods including more plastics. The profit potential for these new technologies is great This is a graph from the same article that shows for a typical 500 ton per day conversion facility that you're going to be losing on the order of about three and a half million dollars a year even with a highly functioning, functioning waste energy facility and that amount is going to have to be made up by what the municipality pays to dump at your facility. On the other hand, because the pyrolysis and gasification technologies are much more efficient and extracting energy from carbon-bearing wastes, they, and because they they stand to offer not only electricity, but also base chemicals, they have a much rosier profit potential that goes into the positives of three and a half million for a similar size facility. Now, I should point out, we're talking about energy here. But even if we were to convert all of our garbage in the United States, through gasification, which is the most energy efficient form of conversion, we wouldn't even scratch the surface of our total energy usage in the residential sector alone. We use in the residential sector about 22 quadrillion bt use of energy a year. And if we were to combust every scrap or gasify every scrap of municipal solid waste throughout the United States, we'd only be able to substitute for less than 2% of that total. This has always been true about waste to energy. Waste to energy is good. Collection of landfill gas is good. If all things being equal, it yields a little bit of energy, but it's never going to be able to provide the energy a city needs or a town needs or, or the nation needs and it needs to be viewed in that light. Nonetheless, the vision as I've told you, for the industry is one of growth. And this means continued proliferation, and innovation, different types of synthetic polymers that can be recycled when and where there might be markets available for them with a bit of composting of yard waste to create high end gardening products. But overall the knowledge that everything else, everything that isn't convenient to recycle in the mix of products that we end collection methods that we have now, can be fed into one of these facilities and converted to energy. And I'd like to close with an alternate, a very alternate vision and this is advocated by the environmental justice movement and an allied movement called the zero waste movement. How many people have heard of the zero waste movement?

Okay, good. So a number of people, they are allied movements with slightly different pragmatic focus. The Zero Waste movement is, is focused more on technology and program development, where the environmental justice movement, which has been around for longer, has argued for an understanding of sustainability that minimizes risk to everyone and has highlighted the very dirty track record of the actually existing waste to energy industry in the United States. Historically, the risks that are associated with gasification and pyrolysis are high. There's no way you can say that they aren't less than risks from landfilling, and incineration. However, they are greater than for composting and recycling. And this comes from the TELUS Institute report that was done for the state of Massachusetts, which was one of the best lifecycle analysis evaluation of risks and benefits from these technologies that I've seen. This is from another study that was comparative study that created two indices, a risk to human health and an ecosystem equality and compared the various technologies, finding anaerobic digestion, which is in the blue boxes to be, by far the lowest, but admitting that pyralysis and gasification is still is quite a bit safer than the methods that we have today. But more more important, I think in you know, my view is, I think, becoming clear here and we can definitely discuss it, more pressing than the acute health risks from these facilities, these new facilities, are the systemic risks that they entail. And the zero waste movement and the environmental justice movement are arguing very forcefully along this line. And I would agree with them that certain technologies perpetuate the status quo of discarding organic material. And what they mean by organic in this case is carbon-bearing both synthetic and biogenic. These, these technologies need to be fed, they need to be fed with carbon, carbon-bearing waste. And that is antithetical to an alternate vision that sees us diminishing synthetics in our in our society and maximizing natural processes of decomposition in handling our waste which are out there for us to reach to. Furthermore, there's absolutely no reason for me to think that if new conversion facilities open up, safe as they may be, that they're not going to continue to cluster in the same areas that have borne the brunt of older generation landfills and incinerators. And furthermore, new research that's just come out again, by the TELUS Institute, shows the great job creation of potential in recycling and composting as compared to to various forms of conversion and landfill disposal. But we do need to bear in mind that, and here I've highlighted, the job creation potential from processing. Plastics, for example, is over at one job per 1000 tons of plastic processing. We need to be mindful of the types of jobs that we're associating with this problematic fraction of our waste. Right now, the plastics industry is fiercely at work trying to stop any forms of legislation that would diminish plastics, consumption or production in every state and every locality. They are fighting strongly against taxes and bans and fees. And what are they fighting for? What do they propose as an alternative recycling, because they don't have to deal with the aftermath of the difficulties that real plastics recycling entails. And if conversion technologies get going, and are another option, this is going to make their position all those stronger.

Julian Agyeman, who is at Tufts University, talks about a notion called just sustainability. And he says it's not enough to talk just about sustainability. As we have been for so long, we need to think about the distribution today and in the future of the opportunities and the risks from the way that we interact with the natural world. And I would argue that this applies very much to the questions I've just been talking about. I find this perspective very useful. When I can, I concede that newer generation conversion technologies may actually be possibly safe, but they are not safe in the in the sense of emissions, but they are not an ingredient of a systemic way to address the problems of waste that have been plaguing us and the problems of material production, that are very much bound up with the with the global environmental problems of the world today. And in this regard, I find a perspective of another another scholar who is at UMass Lowell, to be very useful. Kenneth Geiser talks about three circuits of materials sustainability. One should maximize the cycling of natural materials through natural processes of decomposition, which I've already demonstrated, are out there and ready to go and always have them while while protecting ecosystemic integrity. So this would argue for the maximization of use of natural materials and managing them as waste through natural processes. There has to be some recycling as we know it, some recycling of metals of glass and possibly even paper when it makes sense. But the recycling of any type of material or chemical that involves any kind of toxicity, and again, we're pretty much talking about certain plastics, as well as certain additives to paper that contain chlorine needs to be not only minimized but kept in a very, very closed system in which the emissions from the recycling process are not being exchanged with the natural world. And that's very much not what is going on today in either the recycling or disposal that's taking place. 

So I'd like to conclude with proposing that we rethink this pie, not only in terms of just shrinking it, but also in substituting natural, sustainable materials for synthetic ones. In as as we move forward and waste sustainability, thank you very much. 

Sure, yeah. I'm glad you Yeah. Couldn't get into that.


So I totally agree with that. And it right now, bio plastics are actually worse for the overall system of plastic recycling, and also the impression that the public has about their being a good thing than if they didn't exist. And this is why, number one, for the same reason that you pointed out, a bio plastic that goes into a recycling facility is going to need to be sorted out as residue and disposed is not going to be able to fit or work with the plastic recycling processes and technologies that we have today. So it's yet one more iteration of the heterogeneity of plastics on the end. Furthermore, people do, not you obviously, but your average consumer believes that buying things out of bio plastics because they are going to biodegrade in the landfill, is actually doing somebody a favor. And actually, in actuality, it's making the problem worse, because it's adding that little bit of methane and emission from the landfill. A lot of the problem with bio plastics is that they look just like plastic. And this is supposed to be something that is good about them. But we wouldn't mix up, let's say a wax paper cup with a class with a traditional plastic cup, we wouldn't mix up a bamboo plate with a plastic plate, we can see we can touch these materials, we know that they are different, they're not to be treated as plastic. They're not to be put with plastic and recycling. So I think part of the problem has to do with the fact that the bioplastic industry is still trying to mimic plastic.

The other part of the problem is just what you talked about is infrastructural capacity and a system. Like you were talking about Harvard here, I assume. Right? So Harvard would be in a certain way, sort of a little closed system in that you can route all of what you collect, not through the City of Cambridge Public Works Department, but maybe you have your own contracts with your own processors. So if you were able to sweep through Harvard and tell you know, every concession stand and every dorm, every cafeteria, you cannot use plastics, that's just it command and control regulation from Harvard, you've got to use bio plastics, and then you had a good composting, industrial scale composting, contract and facility in place, then you would have a very nice functioning system, but it would only be in the scale of Harvard and the minute you stepped off the campus, the whole thing would fall apart. So these are the really tough questions about how can we make this transition to these kinds of systems that will actually work. Thank you for bringing that up. I deliberately didn't get into it just because it adds another wrinkle. 

I'm not either.

wondering, um, there's supposedly some organisms you can use to help clean up oil spills, petroleum, if there's any sort of research and the things that make them feel plastic and what their biological processes so cause waste, but I don't know if there's any research into like, another way to get ready.

Well, someone else might know more than me. My understanding is that there are there are types of plastic that can be broken down. By microorganisms in the sense of made to smaller made into micro particles, but they don't become part, they don't become soil amendment, they don't come back into the cycle of life. With bio plastics, yes, yeah, if you have you have to have high temperatures, you have to have controlled conditions. And otherwise it'll take 20 years. But though when bio plastics which are made out of plant materials break down, they they're just like any other plant material, provided there is no additives. Yeah.

Certain aromatic herbs and concentrates. That that is.


Yes, yeah, that'sanother big part of it. Well, I think the most useful programs that address it are programs that focus on things like urban agriculture, urban gardening, community nutrition, because those are efforts to bring urban inhabitants kind of back into an understanding of the cycle of life through the soil and growing and living things. And when you, when you start to see those things, which many children that were raised in urban settings have had absolutely no contact with, you start to think about food waste differently. And this gentleman composts in the backyard, so doI,  I get great joy composting. I mean, if I peel a carrot, I know I can put this in my compost bin. Now, I know that that sounds kind of corny, you know, it's not really a basis for public policy. However, it to get to your question, I do think that if we emphasize more, the very simple connection between most of what we throw out and enrichment of the soil, fighting erosion, public works projects, there's no end of applications for compost, their public works applications. We're not trying to find some new use for a recycled plastic as a stuffing for a jacket or something like that. We know how to use this stuff, we know how to make it we have microorganisms to help us make it that can get over some of the disgust. But the disgust factor is really there. And it's especially acute in in urban settings where you have confined spaces. And you have to have source-separated collection. And it's a very, very serious problem and one that I haven't found in, for instance, in the setting of New York a good answer to. Are people going to separate their food waste and put them out separately. It's it's tough, it's very tough. 

Well, Waste Management and other companies love composting, if it's going to be economically rational and feasible for them, they have nothing against it. And they like to provide it as a menu of services for flexibility with their their clients with their. Now restaurants, number one are automatically have more of a separated stream of food waste, because they don't have the variety of things being thrown out. They also do have the benefit of having labor that can be ordered to source separate or else you're out the door. So the conditions for restaurants and restaurant collection are really good. And that's actually how source-separated organics collection got started in San Francisco and a lot of cities that now have it for residential collection.

risks were lower, and it doesn't have the same problems accomplished in terms of releasing carbonis more widely used.

It is still in its early phases. The reason why it's it is it's quite widely used now for agricultural waste, manure, and like in you know, pit hog manure and things like that, and, and also in crop residues. There's a lot of interest in it and there's a lot of support for it. There's interest in it by the waste management industry, because it does yield some energy. And it's seen as an easier sell politically to communities because it's composting. And it's also by and large, supported by the zero waste environmental justice movement, although there are exceptions to that. And I do see it being the technology that actually I hope is more likely than gasification and pyralysis to take off, but its limitations are that it can handle plastics. And it also requires source separation. You don't want to have a toxic stew going into an anaerobic digester. It doesn't matter if you put a toxic stew into a pyralysis or gasification plant. So it requires if we're getting back to the same question of how do we get residents to separate out their food scraps for collection.

Thank you very much.