Business & Industry

Nov 1, 2017

PURE ENERGY, NOT WASTE

Spent coffee grounds are a popular garden fertilizer, because of their high nitrogen content. Recycled in this manner, they already contribute to an environmentally friendly waste management. But there is a lot more about spent coffee grounds we didn't even suspect.

By NAHAN SULEIMAN

As part of its food production processes, the Swiss food industry produces about half a million tons of organic waste a year. And that's why the food industry is very interested in reducing the amount of waste as well as usefully recycle unavoidable waste whenever it's possible. At the moment, about three quarters of such waste is already re-used for the production of animal feeds. A little more than nine percent is composted and just under 11.5 percent is used in energy production.

A new procedure developed at the Paul Scherrer Institute (PSI), in Switzerland, allows high quality methane to be formed from spent coffee grounds. PSI researchers involved in a pilot project carried out in cooperation with the Swiss food producer Nestlé were able to show that spent coffee grounds left over during the production of instant coffee can be efficiently re-used for other purposes.

In order to carry out the necessary experiments, moist spent coffee grounds left over from the production of instant coffee were made available by Nestlé. The spent coffee grounds were then heated in an experimental PSI facility to a temperature of about 450°C and subjected to a pressure of about 300 bar.

During this procedure, the water contained in the spent coffee grounds transitioned into a state in which it is neither liquid nor gas, known as a supercritical state. This has the advantage that the mineral nutrients contained in spent coffee grounds do not dissolve, as they would in water, but can be easily separated off. The next process step is to turn the residual coffee grounds into methane with the help of a catalyst. 

The first results are very promising: about sixty per cent of the energy contained in spent coffee grounds was converted into methane during the pilot project. "This enabled us to show that it's technically possible to form methane from spent coffee grounds", said Frédéric Vogel, Group Head of Catalytic Process Engineering at the PSI and Professor for Renewable Energies at the University of Applied Sciences and Arts Northwestern Switzerland.

The converted methane can be used in a number of ways. It can be fed into the gas grid or used to produce electricity. The great advantage of this process is that the waste products used in the procedure are often moist but do not need to be subjected to elaborate drying processes in order to be converted into energy.

This means that the energy can be saved, reducing the costs incurred by other procedures such as waste incineration. "The challenge we face with this procedure lies in the different constituent elements that make up organic waste, for which the procedure has to be optimized on a case-by-case basis", explains Frédéric Vogel.

This is where the catalyst used in the procedure plays an important role, which is why the PSI continues to focus on catalyst research. 

However, a more efficient facility is necessary in order to carry out a more reliable field test. "Only then will we be able to extrapolate industrially relevant data from these research results", says Vogel. Such a facility is currently being set up at the PSI. A further important step is establishing the procedure's economic viability.

In the meantime, PSI researchers are already thinking about further uses for spent coffee grounds. Their research is focused on its tried-and-tested application as fertilizer.

The pilot project also showed that the mineral salts separated off during the experiment—in particular the nitrogen bonded in the salts—could provide high quality fertilizer. Researchers are now interested in also following up on these experiment results. 

Contacts * www.psi.ch * Paul Scherrer Institute, 5232 Villigen PSI, Switzerland * Tel: +41 56 310 21 11 *

Fax: +41 56 310 21 99

More Articles

FeaturedArticles

  • Cogumelos01

    Food & Beverage

    May 1, 2017

    From Waste to Gourmet

    Alex Villeneuve, only 21 years old and near his graduation as master beer brewer on the Olds College, realizing the amount of waste (what's left of barley after the fermentation required for beer brewing) whose only faith was the...

  • _MSS8814

    Business & Industry

    Jun 20, 2018

    NEW CYCLE OF INVESTMENT IN ANGOLA

    The economy of Angola is starting a new cycle of recovery, taking into account the steady increase of the price of crude oil and the technical assistance of the International Monetary Fund

  • transferir (1)

    Science & Nature

    May 1, 2017

    Other Side of Aquaculture

    In 2016 the global seaweed trade grossed more than the world's production of lemons and limes, for example. Seaweed gathering doubled on the last decade and nowadays we even have real underwater farms that try to invigorate and capitalize...


  • Chipre1

    Lifestyle & Travel

    Apr 30, 2018

    DREAM ABOUT THE SUMMER

    What if, in 2018, you'd travel for the five corners of the world? It is hard to choose the most beautiful places, but we prepared a list with five destinations rich in history, culture and unique landscapes you will not want to lose!

    ...

  • 1. Technology-Remarkable-Your Paper, Digital

    Technology

    Feb 1, 2018

    YOUR PAPER, DIGITAL

    We all got used to, since school and university age, take notes on paper. Whether in conferences, business meetings or workshops, it was almost ubiquitous the use of notes books in several shapes and formats, since the pocket ones...

  • the7virtues1

    Science & Nature

    Sep 24, 2018

    THE 7 VIRTUES

    Exotic and humanitarian fragrances

    The words "sustainability" and "fair trade" are often discussed in recent times, mainly in the area of food and agriculture. But what they mean to the perfumery? The Canadian company,...


  • 1

    Business & Industry

    Jun 1, 2015

    Where the best office paper is made

    The Portucel Soporcel group is focused on its own brands. This means its sales strategy is to offer a portfolio of brands with distinctive value propositions, reaching out to different consumer segments. 

    Pride of place goes...

  • 1. Ocean-Cleanup-Delete-the-Plastic-Islands-for-Good

    Science & Nature

    Nov 1, 2017

    DELETE THE PLASTIC ISLANDS FOR GOOD

    In 2014, with only 19 years, Dutch Boyan Slat found a possible solution to clean half of the Pacific Ocean within ten years. Slat's plan consists in a floating barrier which takes advantage of the oceanic tides producing a kind of...

  • Culture & Art

    Mar 1, 2015

    Free knowledge for everyone

    Presently, Wikipedia is a normal internet companion, your go-to source when you need questions answered quickly, technical data on any subject or random trivia about virtually any celebrity in the world.