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. 


27 oktober 2014 16.20

Big data on tap

Big data on tap Patterns in data on drinking water consumption can be used to save energy and to detect leakages, says Dr. Martijn Bakker in his PhD thesis.
27 oktober 2014 13.45

Masters of expressions

Masters of expressions Painters of the Golden Age knew like no other how to convey human emotions convincingly. Hamdi Dibeklioğlu demonstrates this with software that recognizes expressions. His set-up is part of an exhibition in the Frans Hals Museum in ...

22 oktober 2014 21.08

Desgevraagd

Desgevraagd De overheid heeft de besturing en beheersing van ICT-projecten niet op orde. Dat kost de belastingbetaler miljarden euro’s. Het ergste is: niemand leert van zijn fouten. De parlementaire onderzoekscommissie ICT publiceerde vorige week ...
20 oktober 2014 16.46

Mathematics of wounds

The workshop on the mathematics of wound prevention and healing last Friday was the kick-off of an international effort to model wound generation and recovery.

17 oktober 2014 10.09

Framing for freedom

Framing for freedom Industrial designer Hakim Sugito MSc. developed a frame to stabilize cameras while filming. He hopes that the system called Waltz will give independent filmmakers more freedom.
16 oktober 2014 15.27

Crossing Majorana's

Crossing Majorana's Micron-sized semiconductor crosses set the stage for Majorana manipulations, which may be used as basics for quantum computing.

  Meer