Waste is Not a Dirty Word
The phrase “valorization of waste” is central to much of the research undertaken by Dr. Pascale Champagne, associate professor of civil engineering at Queen’s University and Canada Research Chair in Bioresources Engineering. Waste valorization is all about asking if waste from any given source is really waste, or if it can be considered a renewable asset.
It is a seemingly simple idea that is complex in its execution. Champagne illustrates the idea with a description of a project that involves growing algae on waste CO2, waste heat, and waste water generated by the local municipality as well as a cement company, which is an important contributor to atmospheric CO2. On an immediate level the objective of the cement company is to sequester its CO2 emissions in the algae and make use of its lower-grade energy, while the municipality wants to treat its effluent.
Yet the process goes deeper still. The algae not only help reduce the environmental footprint of existing industrial activities, but they give the cement company another source of feedstock to combust in their manufacturing activities. Yet, as to wring every last ounce of energy from the process, Champagne introduces another twist: “The other aspect that we’re looking at − and I work on this with Dr. Philip Jessop in Chemistry − is that rather than burn the algae right away, you can first extract some of its bio-oils and then burn whatever is left over, because the oils extracted can be converted to biodiesel.” For this, they apply novel and greener CO2-tunable extraction techniques that can further employ the waste CO2 from the cement industry.
This is an example of the “systems thinking” that Champagne employs in her research, finding the connections between streams of waste in one part of a community, and then implementing technologies to turn that waste into something of value for another part. Analogous are the closed-loop systems in the natural world where the waste of one species helps sustain the life of another.
Of course, implementing such systems among disparate human activities is a huge challenge, and the devil is in the details: “I think that’s what people don’t appreciate about environmental systems. You can’t put all those interactions into one equation. I mean, we have biogeochemical models that try to model everything that might happen, but innumerous factors − biological, ecological and chemical − must be considered. Every waste valorization has its own specific context that must be attended to.” For instance, Canada’s particular climate impacts the species of algae that will grow, and thus determines the algae’s viability as a source of biofuel. Or in a remote Northern community with a small population where a conventional waste water treatment plant doesn’t make sense, a passive system, such as a waste water stabilization pond, might be the best solution.
The multiplicity of contexts and connections might be the reason that Champagne is involved with a staggering number of research projects. From the extraction of useable chemicals from residual biomass, to treating municipal and industrial waste water using eco-engineered passive treatment systems, to helping develop kitchen waste digesters to produce cooking fuel in developing countries, she is exploring opportunities that exist all around us. And as diverse as the projects seem, they all share the goal of identifying waste in one aspect of society and inventing techniques to make it useful in another. “Not only does waste get used again so it’s not immediately discarded and going to landfill, but then there’s the whole aspect of closing the loop in terms of nutrient cycles, water usage, energy consumption and greenhouse gas emissions. And that becomes important, too, in reducing our environmental footprint.”
So the vision that drives Champagne’s work goes beyond waste valorization towards systems that approach a closed loop of waste use. The goals are intimately connected in the pursuit of new systems that move society towards a more sustainable ecosystem of human waste, and perhaps to where waste is no longer a dirty word.
Profile by Lowell Cochrane
(e)Affect Issue 4, Fall 2013