Dispelling Myths About Mixed Waste Processing

Historians of the recycling movement like Steve Miller understand the backlash against mixed waste processing isn’t unlike when single stream was source of pushback and concern.

Miller, CEO of Bulk Handling Systems (BHS), which provides turnkey mixed waste processing systems—the concept, design, engineering, manufacturing, install, service and daily operational support for half a dozen systems in the U.S.—says while his integrated company continues to build many more single stream systems annually, the renewed interested in mixed waste processing is driven by communities’ desire to increase diversion in a cost-effective way.

“Interestingly, some of those who say you can’t have quality out of these facilities ignore the fact that they have been around for a long time and still continue in most parts of the world as the way of extracting recyclables,” Miller says, adding that BHS is this only company that has existing high-volume, technology-driven successful projects.

Miller generously agreed to carve out some time on the Labor Day weekend to answer Waste360’s questions and share his perspective on mixed waste processing. Here’s what he had to say.

Waste360: Can you talk about how your company, Bulk Handling Systems, works in this space of mixed waste processing?

Steve Miller: We first became involved in mixed waste processing in 2006 when a customer of ours expressed interest in the idea. As a result of our exposure to both the European and U.S. markets, we were able to see observe and analyze a variety of approaches to recovering commodities out of waste. The Western Europeans were doing quite a bit of source separated recycling and then treating the remainder of the waste stream to extract fuel sources or RDF. We made the unique observation that the RDF product is simply the light, dry, high caloric value of municipal solid waste stream. In essence, the material is very similar to our single stream. With the exception of glass in some markets, the materials included in single stream are really just the light, dry fraction of solid waste but separated at the curb. We developed a patented process to utilize separation techniques and technologies to extract this material in a processing facility instead of at the curb. Once extracted, we put the material through a process very similar to our single stream process. Of course, in addition to extracting recyclables, the extraction of organic material is also key to our mixed waste processing systems. Once the organic fraction is separated, we offer additional solutions through our Zero Waste Energy subsidiary that extract further value; including high solids anaerobic digestion (AD) and in vessel aerobic composting. Our systems also prepare the balance of material – that which is relatively dry but not suited for recycling – for additional downstream processing as a fuel source. 

Waste360: Advanced mixed waste processing is a controversial topic in the industry. What are your thoughts about the application and long-term viability of this technology?

Steve Miller: We believe that mixed waste processing has a place in the overall basket of processing solutions as an option that can be chosen along with others that are available. Many worry that it will replace single stream or source separated recycling. We see it differently. Rather than as a replacement, we see it working alongside single stream. There have been numerous studies done that show that, even with single stream recycling available in a community, there are still significant quantities of recyclables left in the waste stream. The numbers bear this out in that the recycling rate in the U.S. has been relatively static at around 34%. Mixed waste processing is a way to extract larger quantities of this material. Of course, when it comes to recovery of organics, mixed waste is by far the least expensive way to acquire this material. With all of the efforts around source separated organics recovery, the amount recovered is only around 5%. Again, mixed waste systems make it possible to dramatically increase this figure and there is no way to attain the relatively high diversion targets being discussed today without tackling the organics fraction.

Waste360: What’s the source of controversy?

Steve Miller: The controversy is really coming from the paper industry which is, correctly, worried about the impact that mixed waste processing has on the quality of their feed stocks into the paper-making process. They are right to worry about this but, I believe, wrong to point to the type of processing system used to generate materials. Rather, they should hold all of their fiber supply to a high standard and apply it to any of their purchases whether generated from source separated, single stream, or mixed waste processing systems. It is fundamentally important that the whole industry provide high quality supplies into the paper-making system. It should be noted that the industry has been buying from mixed waste facilities for years. The material produced has met the industries quality specifications or they wouldn’t have purchased it. As more in the industry become familiar with the sort of technology used in mixed waste systems, and concurrently as the technology itself improves, I believe the paper industry will see this as a positive and means to simply capture more high quality fiber.

Waste360: What are the misconceptions about mixed waste processing?

Steve Miller: The most important misconception is that mixed waste systems produce an inferior product and/or the product produced is sold at a discount. This is simply not correct. Every buyer of this material has quality standards that must be met or the sale activity would simply not occur. The mixed waste systems with which I am familiar all produce very high quality material that meets all customer standards. Back to the fiber issue, there is a belief that all fiber is extracted in these systems including wet, contaminated fiber. This is not correct in that only the dry, high quality fiber is extracted and sold.

Waste360: What kind of community is a good fit for this type of processing?

Steve Miller: The most simple introduction is in a community that either doesn’t have a source separated or single stream system existing and wants to increase the amount of material diverted from landfill at the lowest possible cost. Given that so much of the cost of implementing a waste system is in transportation, this is the easiest and least expensive way of getting a significant increase in material diversion. Another good option is for a community that has existing recycling but simply wants to increase diversion and focus on organics recovery. Adding a mixed waste system allows you to do this without the expense of additional routes or containers.

Waste360: What are some of the benefits and drawbacks of mixed waste processing?

Steve Miller: The biggest benefit is that you have access to 100% of a community’s waste stream. All of the material consumed is in the bin and all delivered to the tip floor. From there it is simply a matter of applying technology to achieve separation. The drawback of course is that some of the material may be too contaminated to be included in the recycling stream. However, that material still has potential value as a fuel source and, we believe, further advances in technology will make it possible to cost effectively extract it and make it available as a beneficial product.

Waste360: Can you give some examples of where and how mixed waste processing is making a positive impact in the U.S.? Additionally, what is it about these case studies that set them apart from the norm or the typical community?

Steve Miller: An excellent example of this is in Montgomery, Ala. Prior to implementation of the mixed waste system, they had abandoned an underperforming single stream program. After implementation, they are diverting 60 percent of their residential waste from landfill. Further, the commodities extracted from that community jumped significantly including over 95 percent (up from a benchmark of almost zero) of all of the metals and plastic generated in the city of Montgomery.

There is also an example in San Jose, Calif., where a program was implemented requiring that all commercial waste generated in the city of San Jose get processed prior to landfill. The total recycling rate went from 22 percent prior to implementation to over 70 percent today. The organics recovered from the City produce around 1.6mw of power and significant quantities of compost. This was in a city that had extensive recycling programs available but still missing the majority of the material until the mixed waste system was installed.