Bug discovery could slash costs and cut carbon footprint of water treatment

The team, led by Ameet Pinto, is working on an EPSRC-funded project in collaboration with the University of Michigan. Analysing bacteria found in drinking water system in the US, they detected a previously-unknown strain that is capable of transforming ammonia into nitrates in a single step.

In existing water treatment systems, ammonia removal is a two-stage process involving two different strains of bacteria. First, the ammonia is converted to nitrites, and then in the second step these are oxidised to nitrates that can then be converted into nitrogen gas and evaporated safely from the water. One drawback of this is that the process requires large amounts of electricity. According to the EPSRC, two to three per cent of all electricity usage in Europe and the US is used for wastewater treatment, and some 30 per cent of this can be attributed to ammonia removal processes.

The newly discovered bacterial strain has been given the name commammox (complete ammonia oxidising) bacteria. Other research groups have now also detected it in wastewater plants, groundwater and aquaculture systems.