Anaerobic wastewater treatment project

Currently, medium to large sewage works use activated sludge techniques to treat wastewater. This involves bubbling air through the sewage. It supports the growth of bacteria that clean the water so it’s safe to discharge to the environment. The technique has been used for over 100 years and has played a huge global role in improving public health.

There are challenges with this technique. It takes a lot of energy to pump air through the wastewater (c55% of our waste treatment energy). The process also emits nitrous oxide. 

Improving wastewater treatment process

To improve the technique, we'll be working with Anaerobic Wastewater Treatment (AWT). AWT will transform the energy balance of wastewater treatment. The technique will use different bacteria that doesn't need air to clean the water. It will also not produce nitrous oxide which is 273 times as potent as CO2.

The technique is already used in tropical regions. The warm temperatures help the bacteria perform at their best. For the UK climate, however, they will need some help. We've been following the research into this for over ten years. We're very excited to be now taking it to the next level. 

Our sewage treatment works currently use anaerobic bacteria in digesters. This produces and captures biogas. We use the biogas around our sites as a source of renewable energy. At some sites, we put this energy back into the National Grid.

The AWT process will still be able to produce biogas using this novel process. This is an important factor in helping the water industry achieve its Net Zero targets.