Waste conversion for resource recovery – terminology, infrastructure, regulation and standards

Towards the new hierarchy

It seems so pointless to throw our national resources into a hole and pay to keep them there, just to pay yet again to bring virgin resources back into the one-way stream of our supply chain. Yet, anyone who has witnessed arbitrary “waste” of our environment understands that today’s best management practices are a vast improvement over past accidents.

If the sole aim is to reduce the amount and toxicity of residual waste, sanitary disposal can be handled through advanced landfill or by incineration where waste is “delivered to ashes”. But incineration is still a form of disposal, and disposal does not restore the resource, only placing it permanently “out of the way”. What a waste.

We now have the means to carefully “bake the cake” of the complex residual waste accumulation with a variety of methods that we may collectively recognize as reverse manufacturing. These processes separate waste components at the molecular level and prepare basic resources to be manufactured for new goods. When this capability is properly used as a last resort instead of disposal in an orderly waste management hierarchy, molecular recycling can be called Recovery.

The European Union has recently changed their hierarchy of waste management. They have now officially added a fifth step to their overall waste management plan of choice: Reduce, Recycle, Recycle … Restore … Dispose of. Logic is prevalent; hopefully our own national common sense.

The lines are drawn, but the fine gradations between these waste management hierarchy steps tend to represent a continuum rather than offering clear and discrete categories of action.

what is “Recovery” and how can this step be carried out purely and economically? What should we do to establish this paradigm not only in institutional law, but also more broadly as a universal part of our social and industrial infrastructure?

Conversion for optimal recovery

Conversion of discarded waste materials at the molecular level for the recovery of inherent resources requires two parts: (1) the design technology must provide access to intermediates so that these pipes, liquids and / or gases can be sampled, characterized and modified as needed to ultra-clean end products; and (2) this process of interception, characterization, and modification must be carried out in operational mode so that the information feedback loop facilitated by intermediate sampling is actually performed.

A decade ago, the real-time sensor and computer analysis requirements of the complicated changes occurring within a thermal processing unit’s explosive reactions were far too expensive, requiring huge data management capabilities not available outside universities and military facilities. Today, small and inexpensive computers can assimilate the same data, the algorithms can be applied, and the resulting analyzes become feed-back for programmable logic controls (PLCs) that control the equipment’s moment-to-moment operation.

Energy is the underlying requirement when molecular bonds are to be separated. The surrounding molecules must be sufficiently activated to overcome the strength of each bond to be separated, and the input amount varies depending on the inherent binding ability. This energy can be introduced in several ways, some better suited to managing specific residual waste than others. Some resources have more value at the molecular level than others in the market. The market will, of course, promote cost-effective recovery. Those who believe that an economy should be solely market-based may argue that this guideline should suffice. Still, cheaper is not necessarily better.

Some methods of activating and breaking molecular bonds are more expensive than others. Technical design and operating methods that can efficiently recover resources from homogeneous waste types may not be sufficiently robust for highly heterogeneous raw materials. Technical specifications become important as they define “envelopes” of design and operation according to the input and the intended end product. Allowing processes controls proper use and implements restrictions on using the wrong tool for the current job. These market forces controls should only be designed where optimization for cleanliness and percentage recovery slows down the underlying economy.

As the molecular diversity of the feedstock increases, the nature of bonds requiring deconstruction varies. Some of the most toxic residues are also the most difficult to return; To maximize environmental purity, the conversion process must be optimized to effectively reduce these most residual fractions to their non-toxic constituents. Environmental considerations must lead to conversion technology design and operation towards both maximum resource utilization AND maximum toxicity reduction; these answers to appropriate environmental problems become performance standards.

Many of the technologies available to convert waste into recyclable resources have been around for half a century or more. Our industrial ability to design, operate, monitor and change the process “on the go” is only now able to meet our modern and ever-increasing environmental unit standards. Advances in design and operational control allow scaling operations to scale to fit our community. Conversion of waste at source (rather than regionally) can dramatically reduce the amount and weight of shipment, thus minimizing both cost and impact on transport. Community-scaled, ultra-clean municipal solid waste conversion that is recycled after recycling for cost-effective recycling of our natural resources: this is new. And because it is new, much remains to be done to define and ensure proper integration within this changing paradigm that now informs our waste management hierarchy.

The integrated conversion platform

What are the tools in this new recovery trade? What do these systems look like; where can they be placed? How “clean” is clean?

First: there is no “silver bullet”, no single system or method of operation that can handle any molecular recycling challenge. Our waste stream is simply too complicated. Our best hope is to carefully select “best in class” into a series of classes, each set to manage a breadth of materials such as raw material. We can then combine a package of these selected modules into an integrated process stream capable of optimally receiving, processing, and recovering the largest amount of resources available for conversion in a particular area. The optimal conversion platformTherefore, it would be an integration of subsystems, customized designed to effectively process the region’s materials that require conversion and recovery.

A basic guideline for converting waste to selecting conversion processes has been offered by the Environmental Protection Agency as part of their AgStar program: If the waste is wet, keep it wet; if it is dry, keep it dry.

Of course, “waste” comes in all degrees of humidity as well as molecular diversity, and conversion processes have evolved over time to accommodate these widely different characteristics. Three basic categories of conversion platform or integrated mechanisms: thermal, microbial and chemical / kinetic. Each category contains technical complements that are proficient for conversion across the moisture and molecular profile range.

conclusions

Science must lead this field of Conversion for Recovery, both in the necessary research and development and in the design and operation of integrated platforms for Conversion Technologies. The guidelines developed as environmental safety nets must be based on tested and proven performance, certainly not by arbitrarily assigned prescriptive standards. The full-service environmental control design implemented through permit and licensing must also facilitate a constant process of data collection and analysis on which this science can stay abreast of exploration products.

If Conversion to Recovery requires both design and operational parameters to be met, this is the second step that is usually skipped or only minimally used. This is perhaps most clearly seen in the thermal conversion complement. Doing something with hot, explosive liquids and gases is both expensive and dangerous. Still, there is a difference we can establish between crude “producer” gas and carefully designed “syngas”, just as there is a difference between crude biofuel and specification “biodiesel”.

If technological design allows, but the operations are not ready to act under occasional nailing conditions, the only thing left is to “clean up the mess” after the fact, and this is no different from what can be done with a world-class incinerator. Any system can be operated in an area from clean to dirty. It is the human factor that we continue to ignore, and generally it costs more to run clean than it does to work dirty.

If a conversion technology can be operated without penetrating samples, by doing nothing but taking sensor readings and being ready to act as needed, both points are covered and the system is a conversion technology that is driven for conversion, not destruction or disposal. This is usually the case where electricity and / heat are the desired products at conversion. No molecular recovery occurs when conversion results only in the collection of the energy released by the breaking molecular bonds. The electrical and thermal energy thus obtained may be renewable, but this does not constitute a conversion to molecular recovery.

But when molecular recovery is the goal, the difficult and dangerous industrial step of sampling, segregating and sequestering fractions of intermediate process products should almost always be considered a necessity.

To achieve this most sustainable goal of Conversion for Molecular Resource Recovery, all factors must come into play:

• The technology must by design allow access to and modification of intermediates;

• The mode of operation used collects real-time sensed data about the process. The computer-controlled system performs the necessary analyzes and operates immediately and constantly to correct the operations of the process.

• Both conversion technology and operating mode are chosen to optimize for the recovery of the molecular resources contained in the raw material, including, if necessary, separation and characterization of the constantly changing intermediates.

In this way, our new industrial efforts can integrate whatever conversion technology modules may be needed to tackle the diversity of raw material presented and to perform optimal resource recovery at the molecular level.

© JDMT, Inc 2011. All rights reserved. You may freely print and use this article as long as no changes to its content or references are made and credit is given to the author.