Pee and poo power plant

TU researchers are testing ammonia from urine as a feed for fuel cells. The DHV-led project aims to make plants for wastewater treatment self-sufficient in energy.

Sander Tensen: ‘getting there slowly but surely’. (Photo: Jos Wassink)
Sander Tensen: ‘getting there slowly but surely’. (Photo: Jos Wassink)

A number of technologies have been developed to remove nitrogen and phosphates from sewage water as energy-efficiently as possible. The recently distinguished Anammox method developed by Professor Mark van Loosdrecht (AS) is one such technological application. DHV consultancy chose another tack: in an experimental plant near Groningen, they removed the nutrients chemically in order to optimise energy production. This DHV water innovation project was awarded the 2010 ‘Vernufteling’ award, as it saves energy and recycles phosphates at the same time.

The process involves adding magnesium hydroxide to the wastewater. The magnesium binds the phosphate and nitrate into an insoluble salt, which then precipitates. It is this salt, called ‘struvite’, which is transported from Groningen to Delft and stored in tanks for fuel tests.

“When you heat the salt, ammonia escapes,” explains Sander Tensen, who graduated on the overall system engineering. In fact, it’s a mixture of ammonia and water vapour that enters the system. When heated to over 750 ºC, ammonia will split up into its constituents: nitrogen and hydrogen. The high temperature fuel cell (solid oxide fuel cell) burns hydrogen with oxygen (from the air) while producing electrical power with an efficiency of about 50 to 60 percent. “And no nitrogen oxides or NOx’s are formed,” says project manager Dr P.V. Aravind, from the 3mE faculty’s process and energy department.

“Practice often proves to be a little more challenging,” says Tensen, as he explains that besides the ammonia, water vapour also enters the fuel cell. This not only dilutes the process but may reduce the performance of the fuel cell as well.
“The main thing is to get waste water plants self-sufficient in energy,” says Aravind. Especially in developing countries, sewage treatment is often interrupted by power cuts. Fuel cells fed with biogas from the sewage water treatment, as well as ammonia from urine, should be able to keep the plant going. 


03 maart 2015 09.47

​ 3D hotspots for cancer genes

​ 3D hotspots for cancer genes Genes that didn’t seem important in the development of cancer happen to play a role after all. Delft researchers have discovered new areas in the genome where malicious mutations can occur.
25 februari 2015 10.13

Making technology your business

Making technology your business “Genius is one percent inspiration and ninety-nine percent transpiration”. A quote by Edison in 1903 is still proven to be valid in the course Turning Technology into Business. The final presentations of this course took place on the ...

23 februari 2015 00.53

Twee euro voor je privacy

Twee euro voor je privacy Grote betaling doen? Toets alleen even een vijfcijferige pincode. Overzichten van je verzekeringen; allemaal met één tap bereikbaar. Handig, die digitalisering van je administratie, maar hoe zit het met je privacy? Sebastian Derikx ...
23 februari 2015 00.43

Desgevraagd

Desgevraagd Deze hele week rijdt er geen trein tussen Rotterdam en Den Haag. De omschakeling van bovengronds naar ondergronds spoor in Delft duurt van 22 tot en met 27 februari. Waarom eigenlijk zo lang?

23 februari 2015 00.32

Leuk bedacht: "zelfherstellend asfalt"

Leuk bedacht: "zelfherstellend asfalt" Delta bericht regelmatig over innovatieve ideeën. Maar wat is daar een paar jaar later van terechtgekomen? Hoe staat het bijvoorbeeld met het zelfherstellend asfalt?
19 februari 2015 21.27

An abundance of rare earth metals

An abundance of rare earth metals The large demand for a number of rare earth elements for use in high tech devices has led to an oversupply of others. TU researchers are looking for useful applications of these by-products.

  Meer