Corporate Responsibility

Managing our odour.

Last reviewed:
Our sewage treatment works and pumping stations can sometimes produce odours, and we want to reduce the chance of these unwelcome smells disrupting the communities where we operate. We’ve made a commitment to our regulator, Ofwat, that we’ll reduce the number of people’s homes and workplaces affected by odour by 6,593 by 2020.

An odour control unit at Deephams sewage treatment works.

What’s the problem?

When many of our operational sites were built, they were normally located well away from residential areas. But with continued population growth in the south east, housing developments are now getting closer to our sewage treatment works.

Many of our sites are over 40 years old, and they weren’t designed and built to minimise odour. Unfortunately this means that no matter how well we manage and operate our sites, some people’s homes can still be affected by unwelcome smells.

We’re continuing to upgrade our sites to reduce odour for local communities, with current projects at sites like Deephams. Our targeted approach of focusing improvements on particular parts of our sewage treatment works (for instance, by installing better odour control units for covered wastewater and sludge processes, as shown in the image above) helps make sure we’re installing tailored solutions as efficiently as possible. Click on the case study below to find out more on our upgrades at our storm tanks in Acton:

How are we doing?

After our investments to upgrade our sewage treatment works, we’ve exceeded our target for odour reduction by 12 per cent. Our success in cutting unwanted smells is improving, thanks to introducing odour management plans, installing new odour abatement equipment, and carefully tracking our results. Completing a number of major odour mitigation projects means we’re on target to meet our performance commitment to Ofwat. Here’s how we’ve achieved this:

  1. Carefully maintaining equipment that affects how much odour our sites produce, and ensuring that our day to day operations minimise unwanted smells. This includes undertaking maintenance and improvements at treatment works and pumping stations as part of how we meet all the current practices for controlling odour.
  2. Investing in reducing emissions at Deephams, and other sewage treatment works close to people’s homes and workplaces.
  3. Making sure that any new development on our sites won’t have a detrimental effect on the community.
  4. Adding odour reducing compounds to sewage in our drains to help reduce the odour of waste arriving at our works.
  5. Trialling real time odour monitoring technologies to provide improved proactive control.
  6. Investigating innovative, low energy and low carbon ways of treating unwelcome smells.

Sewage works upgrades.

We’re continuing to improve our sewage treatment work performance. In 2017/18, we made more improvements to reduce unwanted smells at Farnham sewage treatment works, by installing and replacing odour control units, and improving our storm tank cleaning systems. According to our odour management models, this means that 682 fewer homes and businesses will be affected by odours.