Cafe Waste Auditing At The University Of Edinburgh

November 12, 2015

OK its not everyone’s idea of a great time, but today three of the University’s students and staff  volunteered on a waste audit of a sample of the University’s cafes.  The auditing takes place every few weeks and involves getting the bins from the cafes from the day before and monitoring the accuracy of the separation process.  The University operates a four-way separation: glass, ‘dry mixed recyclables’ (hard plastics, cardboard, paper, lids from disposable cups, metal tins and cans), food waste,  ‘general waste’ – meaning that which will end up in landfill.  Since the glass collection is more or less 100% we only consider here the dry mixed recyclables, general waste and food waste here.  Today we received bags of each type of waste from four different Cafes in the University. One was the Main Library and this was by far the largest amount we processed.  The general waste is in a black sack, the mixed dry recyclables in a white sack and the food waste in a clear sack. We took the mixed recyclables sack, weighed it, emptied on the table and then sorted into three:  recyclables, food and general waste.  We then did the same with the recyclables sack and, where necessary, the food sack.  If everyone was a perfect green citizen of the University of Edinburgh, the recyclables sack would contain 100% recyclables, the food waste sack 100% food waste and the general waste 100% waste destined for landfill.  In reality of course separation is not 100% so we did our own sorting of the contents of each sack and then estimated the percentage volume of recyclables, general and food wastes.  We then weighed two of the fractions and worked out the weight of the third by deduction.  This meant for each sack we estimated the % of recyclables, general and food waste by volume and measured the mass of each fraction. The separation process is proceeding reasonably well. There was a high level of compliance for plastic bottles & containers, tins and drinks cans, paper, cardboard.  The food waste sack was also generally just food with few other contaminants.  The general waste sacks were the ones where compliance was poorer, e.g. with food waste and recyclables thrown in with waste destined for landfill.

The most common mistake perhaps was to put disposable cups into the recycling bin. It’s an easy mistake as the cups do look like they should be recyclable!  But because they are usually made of both plastic and card, that cannot be readily separated, they are destined for landfill. Confusingly, the plastic lids of such cups are recyclable, but often the lid is left on or in the cup.  Given the vast amounts of coffee drunk by the students and staff at the University, we urgently call upon someone to invent a fully recyclable or compostable disposal drinks cup. With all the talent in Scotland’s universities and research institutes, surely someone can crack this one? 

What we also observed is that very often people shove their food remains into a sandwich wrapper or other container and put the whole thing into the general waste bin. If they had kept the food waste separate, it would have been put into the food waste bin. Soiled containers such as yoghurt pots, drink bottles, etc., were also common and these are treated as contaminated if the recyclables bin and end up in landfill. The people who manage all of this for the University community report a real improvement over the past few years, so well done everyone!  However, a lot of improvement is still needed.  

The information from the waste auditing is used by the University to target locations where compliance rates are lower. It is also provided to the waste contractor who manages all the University’s waste to help inform their understanding of compliance.  If you would like to get involved as a volunteer in this process, please contact me (Simon Shackley, simon.shackley@ed.ac.uk) and I will pass on your details.  I’d recommend if you want to do something ‘concrete’ for food and sustainability. 

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