I stayed at a hotel recently that had soap in a box on the vanity countertop. Opening the box, I found an elliptical bar of soap with an elliptical hole in it — sort of an elliptical annulus. Puzzled, but suspecting some ecological significance, I read the box hoping to find an explanation. The box was the typical rough-textured, brown cardboard “made from natural recycled packaging printed with soy-based inks.” The narrative further explained that the “soap is cruelty-free and contains no animal fat or by-products.” And then the explanation for the hole: “This innovative ergonomically shaped ‘waste-reducing’ soap has been designed to eliminate the unused center of traditional bar soaps.”

All of these features are admirable efforts toward an ecologically sound and guilt-free bath experience. But the hole provides no “waste-reducing” quality. The thin sliver of soap left at the end of a traditional bar (which is eliminated by the hole in the green bar) is typically discarded because it is hard to handle in lathering the wash towel. But the elliptical soap with a hole dwindles down with use to one long sliver that is even more difficult to use and, in fact, easily breaks, leading to more waste than with a traditional holeless bar of soap. A much-better approach is to recognize that wet soap is soft and can easily be melded onto a new bar of soap, leading to zero waste.

This is an example of well-intentioned efforts at eco-friendliness gone wrong because there was no in-depth thinking about the details. While less than a blip on the full ecological radar screen, it represents the faulty thinking that can lead to wasted efforts and squandered resources in the name of greenness.

More significantly, pitfalls await society’s attraction to biopolymers and “biodegradable” as a substitute for recyclable. Biopolymers use sustainable corn and sugar cane sources as a replacement for petroleum-based polymers commonly used for beverage bottles. However, the present versions of bioplastics, while appearing to be identical to PET beverage bottles, can’t be recycled in large quantities mixed with petroleum-based plastics. Biodegradation as an alternative to recycling of bioplastics implies that the materials can decompose into fertilizers for growing more corn and sugar cane. But biodegradation requires composting under controlled heat and humidity, and each version of bioplastic has its own set of degradation parameters.

Biodegradation doesn’t take place in landfills, the traditional end point for nonrecycled material. Meanwhile, as considerable effort continues to solve the practical problems associated with bioplastics, packaging producers have concentrated on significant reductions in the mass of petroleum-based polymer used in each bottle through design and manufacturing changes.

So the groundswell of attraction to the sustainability implications of “bioanything” must be tempered by the realities and practical details of their implementation. For example, the impact of bioplastics on food cost and availability, and the energy requirements and carbon footprint of community composting sites complicate decisions on the use of such technologies. The mandate for sustainable material and energy rightly urges increased efforts to transition such technologies to commercial use, but these efforts require honest examination of the details and full life-cycle analysis to assure real benefits.

The backdrop on my desktop reads “Don’t Believe Everything You Think,” at least initially. Let the hype and emotion settle and then revisit the thought by rationally checking your assumptions and data. That’s not as much fun, but it avoids false hopes and pain later.

— Howard A. Kuhn

Howard A. Kuhn is R&D director of The Ex One Co., and is responsible for developing and implementing direct-digital manufacturing and tooling technologies. Kuhn is also an Adjunct Professor at the Univ. of Pittsburgh, School of Engineering, where he is involved in the digital manufacturing of scaffolds for regenerative medicine.

Edited by Leslie Gordon