Odour Response in Westbury

Odour Update: Northacre MBT Facility; Westbury

We have been receiving an increase in odour reports over the last couple of weeks from some residents in Westbury, and we recognise the impact this can have on daily life and activities. Ensuring that local communities are protected from environmental impacts is a key priority for the Environment Agency.

We regulate the Northacre MBT facility and, following both community feedback and our own monitoring, we acted quickly to engage with the site operator to understand what was causing the increase in odour and to ensure action was taken.

What has happened and what is being done

We are aware that some residents have recently experienced stronger or more persistent odours linked to the facility. Whilst our monitoring has suggested that these have generally remained low-level and short-lived, we appreciate that an increase in odour levels is unacceptable.

The operator’s investigation identified a fault within the site’s biofilter system, which is used to control odours. With support from an independent specialist, it was confirmed that a sensor fault caused the system to become too wet. This reduced its ability to treat odorous air effectively.

To address this, the operator has:

• Replaced the faulty sensor
• Installed a backup system to help prevent this happening again
• Regenerated the biofilter this week to restore performance

These actions are expected to improve airflow and reduce odour over the next few days.

Environment Agency staff monitoring for odour in Westbury

We continue to visit the site regularly to ensure measures are being taken to minimise off-site odour and we are maintaining increased odour monitoring to make sure that odour levels return to an acceptable level as soon as possible. If needed, we will take further action to ensure the site operates in line with its permit conditions.

We continue to work with our partners, including Wiltshire Council and we will continue enhanced odour monitoring in the area and remain focused on reducing odour levels. We are committed to keeping residents updated and ensuring residents' concerns are heard and acted on. Please keep up to date with the latest information by checking back on this website and following our social media channels Environment Agency - South and South West | Bristol | Facebook and Environment AgencySW (@EnvAgencySW) / X