News from the UC Sustainability Office

Composting Coffee Cups Trial: Chicken Carcasses and Coffee Cups

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The Sustainability Office is always looking for new solutions to waste issues and has recently trialled Selwyn District Council’s “HotRot unit” to see if single-use coffee cups can be composted in this unit and it seems like they can!

How does the composting work? The cups are put into a pit and processed through a mechanical composting unit – The HotRot – which is an enclosed vessel with an auger. The cycle is 14 days and during this time the population of microbes escalates because they have so much food (not just the coffee cups but also chicken carcasses, YUM). All this activity raises the heat and accelerates the composting. At the other end brown composting material emerges, which can be used as garden compost!

Collecting the cups

Collecting the cups

Checking the contents

Checking the bin content

Further testing was needed however, which is now underway. From September until November we are trialling a separate single-use cup collection system in the Undercroft and Café 101, so we are now two-thirds of the way through.

So far the trial has been a success. We have been looking at these things:

  • What is the level of contamination in the blue hooded bins? In other words, is there anything else in there apart from single-use cups?
  • Are people using the bins?
  • How interested is the UC community in the bins?

We have found that there has been a low level of contamination, although in one area (the Undercroft), contamination is higher with some people not taking the lids off. Overall the bins are getting a good level of use, and we have already diverted over 2000 litres (by volume) of waste from landfill. This tells us that expanding the trial in 2015 would have a significant positive environmental impact!! We have also found that the UC community has been very enthusiastic about the blue bins and us taking positive action on coffee cups on campus, a bugbear for a number of years. Yay!

We will be doing a proper analysis in November when the trial ends. If all is good, we will be expanding the number of blue bins in 2015, and getting ready for a more significant change in how we do recycling in 2016.

Into the HotRot!

Into the HotRot!

Checking the resulting compost

Checking the resulting compost

The blue bins finally make it possible for us to switch our cafes over to biodegradable packaging, which we anticipate happening in 2015 – if all goes well with this trial and the contamination remains low!!

So please note: these collection points are for empty cups only!! No pie wrappers or lids! Look out for the blue hooded bins and help us make the trial a success.

coffee cup trial bin and poster undercroft

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Author: Puck Algera - UC Sustainability Office

Puck worked at the Sustainability Office at the University of Canterbury in New Zealand. As the Sustainability Projects Coordinator, she kept busy with student and staff engagement, providing strategic input and advice and organising sustainability-focused events.

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