Wednesday, 28 March 2018

What the Energy Group think about waste

Waste (and especially plastic waste) is much in the news at the moment and so the energy group decided to focus on that for their last meeting. I think many of you will be interested who didn't come to the meeting: this post is based on the minutes I have recorded. Blanca, Margaret, Bill and I (Nicola) had all prepared some material to discuss.

Blanca – how to reduce your household waste to very little

The waste hierarchy is conventionally Reduce, Reuse, Recycle, Recover but Blanca has expanded this with some R’s on the front: Reflect (think) – Reject – Reduce – Reuse – Repair.

Blanca and her partner tracked their waste for a month and managed to get it down to an impressively small volume as shown in this picture.

This is the tiny amount of waste that Blanca and her partner generated in one month. Impressive!

They didn't make it easy for themselves by eating out all the time. They only ate away from home twice ☺ Here are some of their tips:
  • Get fruit/veggies from an organic box or market (bring your own reusable bags) 

  • Re-fill existing containers for dry goods, soap and deodorant etc:
    • Daily Bread, Arjuna, Lush
  • Or buy in large quantities to reduce packaging
  • Use a reusable water bottle, take sandwiches in a boc’n;’roll
  • Menstrual cup, menstrual underwear 

  • Drink tap water 
(filter it if you want)
  • Make your own bread/yogurt - Buy local products – reuse containers (honey, milk, etc) 

  • Keep food in reusable containers or wrap e.g. BeeBee Wraps,

Blanca showed us her Boc’n’roll which is great for wrapping sandwiches or other food and can be wiped clean or machine washed. You can buy them or make your own. Here is a video showing you how (in Spanish but you don't really need the words to understand what is going on).

BeeBee Wraps are waxed cloths. You can get them from various places in Cambridge.

What if you want to buy from supermarkets?
We discussed what to do if, like most people, you buy food from supermarkets. This makes avoiding packaging more difficult but there are ways. Produce such as apples is displayed loose and bags supplied but you could bring your own. String bags would be ideal. For produce which is weighed, some shops (at least in Belgium, apparently) allow you to weigh your own produce and print a label for you to stick on. You could use your own bags or containers for this.

For dry goods (such as nuts), you can get dispensers that allow you to fill your own containers but many shops refuse to install these on the grounds of health and safety. We think this is not actually because of legislation, more to do with potential liability issues and hence insurance. If someone becomes ill from the food, was it the food or your container?

We had an idea for another way round this. What if supermarkets supplied reusable containers that they then take back and clean for re-use? This means the supermarket is in control of the packaging, it can even be branded, and it can be re-used many times.

Blanca – marine conservation workshop

Blanca won a competition for a place in the solutions showcase at Plastics in the Ocean marine conservation workshop. There was a variety of solutions presented including:

  • Technical developments to recycle ‘difficult’ plastics
  • BeeBee Wraps reusable food wrap
  • Packaging to replace polystyrene, using waste fungal material
  • Flute furniture, made from recycled fibrous material such as paper, cardboard and wood.
  • Pyreg – pyrolisis processing for municipal waste material yielding energy and a valuable fertiliser.
  • Milk dispensers for supermarkets, to eliminate the need for plastic milk bottles (from CamCattle).
  • (Blanca’s idea) A manual for businesses to help them move away from plastic in the supply chain, showing how this is possible without infringing health and safety regulations.

Nicola: plastic litter and biodegradable plastic

Some supermarkets are moving over to bio-degradable packaging, due to the outcry over plastic in the marine environment. Is this a good way to go? I did some research to put this into context.

What happens to plastic bottles>
  • Only 2% of plastic bottles are picked up in litter – but this is still 0.25 billion bottles (in the UK).  Not much UK plastic waste ends up in the ocean. Most comes from developing countries with poor waste collection infrastructure. It ends up in rivers and floats out to sea.
  • In the UK a fifth of bottles end up in landfill, where it is generally supposed they remain forever but it is very possible that bacteria will evolve to break them down, probably generating methane gas.
  • Another quarter of plastic bottles are incinerated. Presuming they came from oil, this also contributes to global warming.
Would a deposit scheme work?
A deposit scheme for bottles would reduce litter but does nothing to reduce carbon emissions. Also, as was pointed out, a deposit scheme can have unintended consequences. There are horror stories of rubbish bags put out for collection being torn open by people looking for bottles – and the other contents strewn across the street.

Paper bags are worse than plastic in many ways but this could improve.
Some people propose paper bags as an alternative to plastic. Life cycle analysis generally finds paper has a worse environmental impact than plastic in all categories, mainly because of the impacts of farming to grow the source material. Paper is especially bad for water consumption and eutrophication (excess nutrients in water courses from fertiliser run-off causing algal blooms and dead zones with no oxygen). However, both of these impacts can be reduced with good farming practice, being more efficient with fertiliser and water. For example Futamura, who make cellophane™ (biodegradable bio-based film), claim to have reduced the eutrophication due to their supply chain by a factor of three between 1993 and 2010.

What do bio-degradable/bio-based mean?
There is confusion in the plastics world around the meaning of terms such as bio-degradable.

  • Bio-based means it is made from mainly plant material.
  • Bio-degradable usually means it can be broken down to simple molecules by microbes in soil or compost - but not necessarily in a marine environment.
  • Compostable means it bio-degrades in industrial composting conditions in a reasonable time – this may require high temperatures which are not normally achieved in a garden compost bin and certainly not in the ocean.

(This is a vast simplification - there is a more detailed explanation here.)

Material that is bio-based is not necessarily bio-degradable and vice versa. So if something is bio-based that does not mean it is compostable.

Bio-based plastic can have a high environmental impact compared to normal plastic because, as with paper, there are impacts from agriculture (but some plastics are made from waste products).

If something is bio-degradable on land that does not mean it will decay in the sea.
Bio-degradable plastic littered on land will decay, but it often persists in the marine environment due to the low temperature, low oxygen and low light conditions. So if it has not already broken down by the time it hits the sea, it is likely to contribute to plastic pollution and damage marine ecosystems.

Many composting facilities reject all plastic regardless of if it is compostable or not.
Also, although bio-degradable plastic is usually compostable, we are not supposed to put it in the council compost bin. Amey did not respond to our specific questions but we have heard informally second hand that ‘it takes too long to decompose’. Besides which, at many industrial composting facilities workers are instructed to remove all plastic from waste going to composting and there is no equipment to distinguish compostable plastic from conventional. So bio-degradable plastic ends up in landfill or going to be incinerated anyway.

Bio-degradable plastic sounds like it ought to be sustainable but it usually ends up in landfill anyway.
If we have bio-degradable plastic packaging it is difficult for us to get rid of sustainably:

  • Not in the green bin because it takes too long to decompose
  • Not in the blue bin because it isn’t recyclable and may even contaminate the recycled plastic streams.
  • It can go in the black bin – and end up in landfill where it may not may not stay inert for ever.
  • If we have our own garden compost bin it might be OK to put it there – but this may not be hot enough to activate the composting process. (It is possible to insulate your compost bin to enhance the process, but you need to make sure it gets enough oxygen too.)

In summary - bio-degradable plastic is hard to dispose of sustainably and doesn't fix the problem of marine plastic pollution. We need another solution like avoiding single use packaging altogeher. This makes Blanca's  suggestions even more important.

Margaret: how to minimise construction waste

A very large fraction of our waste is construction waste. Most of this is bulky but non-toxic. However, producing stuff like steel, bricks and cement takes a lot of energy so even if it ends up in landfill there are a lot of unnecessary carbon emissions associated with it. Builders are supposed to take their waste to handling centres where it is sorted and some of it is salvaged. But the ideal would be to avoid waste in the first place. Here are some tips for builders that Margaret recommended. If you have some building work done, ask your people what they do about waste.

Minimising waste at the construction site

  • Specify components that fit the design – for example get Tall Wall OSB boards that are the right height, avoiding the need for splicing and cutting to fit.
  • Keep waste separated on site. This makes it easier to salvage bits that you need.
    • Bins or bags must be assigned to metal, plastic, wood etc.
  • Limit use of adhesives and treatments that make stuff hard to recycle. 
    • For example bricks that have been joined with lime mortar are much easier to clean and reuse than ones with cement based mortar. However cement repels water more effectively and can be longer lasting - unless it is too rigid and causes the bricks to explode! There can be a trade-off between durability and recyclability.
  • Build time for recycling into your quote and time estimate
  • Dedicate time at the end of each day for cleanup.

What about treated wood?
If you have waste wood that has been treated, how can you dispose of it? We have no answer to this. You certainly should not burn it in your own fire or stove because this will generate horrible air pollution.

Recycling companies
Companies that help to recycle construction waste locally (ish) include:

  • Salvo has a directory where you can advertise stuff available or what you want. Ads are free except if you are dismantling/demolishing a building and advertise the contents.
  • Specialist recyclers include:
    • Solopark for period home supplies including bricks, tiles, paving and timber
    • Cambridge wood fuel make HotLogs from untreated wood
    • NMR for scrap metal
    • Emmaus for furniture and fittings

Bill – waste to energy

Bill described some options for generating energy from waste (not just plastic waste) including:

  • anaerobic digestion (for food and plant material) generating methane gas and a digestate which is good for fertiiliser
  • gasification (for any combustible waste) generating, typically, hydrogen and carbon monoxide, which can be reformed with steam to make other gases including methane.

AD is widely used these days, usually generating electricity directly but increasingly the methane is cleaned and injected into the grid. Gasification was historically used to make gas for heating from coal but this process can be adapted for biomass and integrated with carbon capture.

Hydrogen - our next meeting topic
This got us talking about hydrogen. Is it really practical to generate this in a low carbon way and burn it in our homes for heat and power? Bill thinks so, but many of us don't know much about it so we chose this for our next meeting topic.

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