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 april 2015 00.41

Blikmans is gratis

Blikmans is gratis Een robot met emoties, het moet niet gekker worden. Het afstudeeronderzoek van werktuigbouwkundig ingenieur Suzanne Weller leverde geen écht voelende robot op, maar wel een manier om hem emoties te laten uitdrukken door middel van ...
27 april 2015 00.36

Desgevraagd

Desgevraagd Heb je een knagende vraag, dan kun je die tot 1 mei indienen op wetenschapsagenda.nl. Delftse onderzoekers laten deze kans niet aan zich voorbij gaan.

27 april 2015 00.21

Leuk bedacht

Delta bericht regelmatig over innovatieve ideeën. Maar wat is daar een paar jaar later van terechtgekomen? Hoe staat het bijvoorbeeld met het plan om de kleuren te bepalen van een verborgen schilderij van Van Gogh?
21 april 2015 13.39

Sailing for plastic

Sailing for plastic Ocean Cleanup, founded by former TU Delft student Boyan Slat, announced an expedition to search for plastic in the Pacific Ocean in August this year.

17 april 2015 07.41

Ice-propelled nanosatellites

Ice-propelled nanosatellites Hydrazine, one of the most widely used rocket propellants, is toxic and severely carcinogen. Why not use water instead? Delft researchers are working at a new propulsion concept for ice-propelled nanosatellites.
16 april 2015 15.36

Phones leading the way in Senegal

Phones leading the way in Senegal A Delft team won the Transport Prize in the Data for Development (D4D) Challenge. They showed how to use mobile phone data to optimise road planning.

  Meer