How to turn your poo green!
I’ve often fancied a compost toilet as I feel a bit guilty flushing litres of perfectly decent water away when there are shortages across the world.
And then I’ve thought about what we actually flush away; well you don’t need me to tell you what THAT is, but isn’t there some kind of power to be harnessed from our waste products?
According to Yorkshire Water there is!
They’ve been busy with a £30 million project at the company’s Esholt sewage works in Bradford, installing the UK’s first BioThelys Sludge Treatment Plant.
It reminds me of Mr Green’s mother who used to follow the horses down the road with a shovel to collect you-know-what for her garden!
But this isn’t about making compost, this is about taking human waste and effluent and using it to create energy to run one of Yorkshire Water’s largest sewage facilities. Common industry practise dictates that this erm, liquid gold, is currently landfilled or incinerated but Yorkshire Water is pioneering a more sustainable route for sludge disposal -thermal hydrolysis system (Biothelys) combined with anaerobic digestion.
Thermal hydrolysis is a process that uses heat and pressure to break down sewage sludge prior to treatment by anaerobic digestion which creates methane-rich biogas that can then be burned to produce electricity which in turn will be used to power much of the plant. This results in a carbon efficient process and means the plant is no longer reliant on mains electricity.
All power to poo!
But that’s not all; this is the part where my mother in law will be sitting up and taking notice. The digested sludge generated after thermal hydrolysis is classified as ‘enhanced treated’ which means it can be legally applied as a fertiliser or soil conditioner for all crops including cereals, vegetables and salads as well as for horticultural purposes.
Ben Roche, Manager of Energy and Carbon at Yorkshire Water, explains the rationale: “Each year we receive an overall electricity bill for approximately £45 million with 70% of our carbon footprint coming from electricity – a footprint that currently stands at 453,000 tonnes of CO2e.
“At the moment we already generate a third of the energy we use on site at Esholt through renewable energy technologies, but our aim is for this huge facility to become fully energy self-sufficient by 2015.
Energy from waste
Not one to rest on their laurels the company is also currently trialling a process to recover energy from waste products found in its sewage works, such as sanitary wear, cotton wool buds and toilet paper. And if that’s not enough Yorkshire Water are currently creating carbon-neutral building bricks out of sludge. If the trial proves successful and the bricks are approved for building use, it has the potential to revolutionise both the construction and water industries.
I’ll never look at sitting on the throne in the same way again!
What about you – what amazing green story have you read in the news recently?
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