A type of bacteria accidentally discovered during research supported by the Engineering and Physical Sciences Research Council (EPSRC) could fundamentally re-shape efforts to cut the huge amount of electricity consumed during wastewater clean-up.
The discovery has upended a century of conventional thinking. The microorganisms – ‘comammox’ (complete ammonia oxidising) bacteria – can completely turn ammonia into nitrates. Traditionally, this vital step in removing nitrogen from wastewater has involved using two different microorganisms in a two-step approach: ammonia is oxidised into nitrites that are then oxidised into nitrates, which are turned into nitrogen gas and flared off harmlessly.
The outcome could be a big rethink regarding the energy-saving innovations developed over the last two to three decades in the field of nitrogen removal. Wastewater treatment is a huge consumer of electricity, accounting for 2-3 per cent of all power usage in western countries, and no less than 30 per cent of its energy bill results from the need to remove nitrogen. Most of the sector’s efforts to reduce its energy use have focused on the two-microorganism approach.
Read more at Engineering and Physical Sciences Research Council.