General Chat

We have a separate small bin in the kitchen for all food waste; The following is what happens to it after it is collected. I thought it might be interesting for people to see.

What happens to your food waste?

Food waste in Gloucestershire gets taken to Andigestion in Bishops Cleeve to be processes. This is what happens at Andigestion:

After leaving your kitchen caddy, food waste embarks on a remarkable transformation process that enables it to generate clean, green and eco-friendly energy for local homes!

Something rather special happens to your food waste once it arrives at our recycling plant just outside Bishops Cleeve near Cheltenham. After leaving your kitchen caddy, it embarks on a remarkable transformation process that enables it to generate clean, green and eco-friendly energy for local homes AND helps farmers grow bigger and healthier crops.

It’s been estimated that just one caddy of food waste generates enough electricity to watch a football match on TV, and for every eight banana peels we recycle enough energy can be produced to boil a kettle, but what happens to transform it into renewable energy once it leaves your home?

The 34,000 tonnes of food waste a year which comes from homes and businesses all over Gloucestershire is the ‘fuel’ for our anaerobic digestion process. Starting at the plant the food waste is separated from any packaging which is recycled where possible. The food waste then enters a tank and mixed into a pumpable ‘soup’ while a macerator reduces food particles to below 12mm to ensure all particles can be fully heated in the next stage of the process.

This ‘soup’ is then heated to 70°C using the waste heat from the electricity generator, for one hour, to kill all unwanted pathogens.

Following pasteurisation, the food waste is pumped as a liquid into large tanks called digesters which contain cultures of anaerobic bacteria to digest the waste. During this process, the bacteria give off methane which we collect in large bags above the tanks. The methane (or Biogas), is then fed either to a generator to produce electricity which powers the site, or to the Biomethane plant to produce biomethane (similar to natural gas) which is pumped into the local Bishops Cleeve gas main. 

The biogas that we produce can be stored on site enabling us to deliver energy when people need it - a huge advantage over other renewable systems that can’t efficiently store power or only produce it when the elements allow. The remaining digested liquid is then screened and pumped into a storage tank ready to be used as liquid fertiliser which with its high values of nitrogen, phosphate and potassium, provides a very eco-friendly and sustainable resource producing bigger, stronger crops and a better yield per acre for farmers. 

At our Bishops Cleeve plant, we are very proud to have recently injected a record 11 million cubic metres of biomethane gas into the national grid - enough energy to power 10,000 homes for a year!

So next time you squeeze out a teabag or scrape your plates into your food waste caddy, remember you are playing a vital part in shaping Gloucestershire’s sustainable future!

Ann, Thank you for posting this.
It is very interesting. Presumably something similar happens wherever food waste is collected. I will have to check our local council website.

I put banana skins in our garden compost bin. Am I depriving the 'grid' of a power source ?

I thought that Gwyn as well. Sometimes I put them in the compost and sometimes in the food bin. (depends how enthusiastic I am about walking down the garden to the compost bin in bad weather. But you are feeding the plants so it is swings and roundabouts really. :-D

That is exactly what happens at our recycling plant here. When I worked in the local school, the children went on a trip to see what happens to all the waste and food. Was very interesting except for one thing....the smell!!! It was pretty awful and glad we didn't stay there too long!

Thank you for posting Ann.

We keep 2 small bins for food waste. One goes to the council and one is for the wormery / garden compost.

This way I can generate compost to grow vegetables but still contribute to the electricity supply.
I can’t understand why all councils are not providing food waste bins.

I can't either Von. I hate it at my daughters because all food waste goes into the general waste bin. I had forgotten how that can smell.

I think ours goes into making compost.

I’m sure I read once that banana skins were good for the roses.

That was interesting and shows what an efficient process can do. Like Von and Ann I can't understand why all councils aren't doing it either. Ours don't and we have to put it in with the other rubbish. We bag it up in old cereal and other bags to save having to wash the bin out. Our council used to be very good about recycling too and in the 70s if we tied our newspapers up and left them at the side of the bin for recycling they gave us a discount on our rates.

Ours goes for recycling as described above. My two sons live in different counties and one has no food waste collection, while the other has had one for a long time. His council doesn't supply compostible liners, whereas ours does, so every so often I used to send him a roll.

We were down visiting a couple of weeks ago and I was apologising for not having the usual roll of liners, but he said it was OK as the council had banned them!! I seem to remember an earlier thread when someone else said the same thing about their council. Son is allowed to use a single sheet of newspaper if he wants.

Strangely we used to be only allowed to use special biodegradeable bags but the last year or so we have been told we can use any bags so I have often used bread bags. From the write up it looks as though they have the facility to take the bags out.

We are not allowed to use plastic bags.
I usually use newspaper for example if wrapping a chicken carcass, but smaller items, - very few in this household, get placed in a recycled paper bag... I use the ones which have held dispensed medications.

From our council website.............

You can also compost your food waste for your own use, eg in your garden or allotment.
How to store your food waste
Each property gets a 5 litre caddy to use indoors and a 23 litre caddy to store outside. If you live in a flat you'll have a small caddy and a large communal bin.

Keep your food waste in the small caddy somewhere inside your home, eg in your kitchen
When your caddy's full, move your waste out to the bigger food waste bin for collection
The council doesn't collect from small caddies.

Compostable liners
You can use compostable liners or paper (eg newspaper or kitchen roll) to line your caddy if you want to. Don't use plastic bags.

You can buy food caddy liners made from corn starch or paper from most supermarkets and hardware shops. You can also buy them online from various sources.

I put out so little for food waste that I don't need a large bin. They always collect my small bin and empty it.

Here in the Highland Region, they only collect food waste in Inverness and suburbs - nowhere else in the very large region.

The Inverness residents are only allowed to use compostable bags for their food waste. No plastic bags, paper bags, or newspaper.