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Trash, Treasure and Trepidation

Few words evoke such negative connotations as the word “waste”, especially if the word “incineration” appears after. Yet to pin down what waste is and is not, is complex not least for policy makers. Furthermore it is compounded by use of the seemingly benign term “residue” or “residual”, suggesting a modest leftover, which of course can be lethally misleading. After all one man’s trash can be another man’s treasure, or his trepidation. And there’s more than enough trepidation in the world today.

The authors also point out that when such unwanted outputs are removed from a water or air discharge as a part of emissions treatment, it is tends to be concentrated as a solid “waste”. Sewage sludge from wastewater treatment plants (WWTP) is a typical case in point of how treating one “unwanted output” gives rise to another. In total, the annual global waste generation is estimated to be 7 to 10 billion tonnes of which municipal solid waste (MSW) is around 2 billion. Around five percent of the global waste generation originates from “water supply, sewage treatment, waste management and land remediation”. No surprise is that MSW per capita increases with income level, a factor ten span between low and high income. The developed world accounts for 1 billion tonnes. The good news is that per capita generation rates have been stable since 2005 after having doubled in period 1970-2000. The developing world accounts for the other billion.

Herein lies the challenge and the opportunity. Per capita generation in many developing countries is relatively low. 2 billion people have no access to solid waste collection and 3 billion people lack access to controlled waste disposal facilities. The developing world is all set up for the double whammy of population increase and economic growth further exacerbated by urbanisation. The report estimates that lower income cities in Africa and Asia will double their MSW generation within 15-20 years. By 2030, 32 of the estimated 41 megacities, cities having a population of at least 10 million, are in the developing world.

In it’s ‘Global Food Losses and Food Waste report from 2011, the UN Food and Agriculture Organisation (FAO) estimated that “roughly one-third of the edible parts of food produced for human consumption, gets lost or wasted globally”, about 1.3 billion tonnes per annum. An important distinction is made between “loss” and “waste”. The latter is recognized as a distinct part of food loss because the drivers that generate it and the solutions to it are different from those of food losses. Food waste refers to discarding or alternative (non-food) use of food that is safe and nutritious for human consumption along the entire food supply chain, from primary production to end household consumer level. Post-harvest losses due to cosmetic specifications of fresh agricultural and horticulture products such as fruit and vegetables, is contentious issue but something that we as consumers can influence directly. An ugly apple or double root carrot is nutritionally the same and tastes no different than a cosmetically correct one.

Clear is that a waste is in actual fact a resource that has yet to be attributed a value, which also may include the cost benefit of its avoidance in the first place. In short, waste and how best to deal with it is entirely context dependant but is essentially about finding that value. Material recovery, nutrient recovery and energy recovery are complementary to one another. Recovery is the fourth “R” in the waste hierarchy principle reduce, reuse and recycle. Together the four R’s form the basis of an efficient holistic waste management system in an increasingly resource constrained society. Gorge Farm, Henriksdal and Zell am See along with the many other projects and installations that have been featured in this publication over the years, serve as inspirational  testimony to the diversity of situation adapted solutions out there.

Editorial from issue 5-2016 (88)

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