Withyhedge Landfill Site

Withyhedge Landfill Site – Air Quality Monitoring

The Withyhedge Landfill Site, situated roughly five miles north of Haverfordwest (just east of the A40 and north of Haverfordwest Airport), is one of the main waste disposal facilities serving Pembrokeshire. It is operated by Resources Management UK Ltd (RML), now part of the Dauson Environmental Group.

Withyhedge is a fully permitted landfill, authorised by Natural Resources Wales (NRW) under Environmental Permit EPR/MP3330WP and is permitted to accept non-hazardous, unrecyclable waste. The site has a current permit to accept up to 250,000 tonnes of waste per year, although this is subject to review by Natural Resources Wales.

Withyhedge must operate under strict environmental permit conditions imposed by its regulator, Natural Resources Wales (NRW).

That includes:

A robust gas-management system to safely collect landfill gas (such as methane/CO₂), prevent its uncontrolled escape, and either flare or treat/utilise it.
A leachate collection and drainage system, to prevent potential contamination of groundwater or surface water.
Monitoring through boreholes (for gas and leachate), with regular sampling to ensure compliance with environmental standards.

Once disposal operations cease and landfill cells are capped, RML will remain legally responsible for aftercare, including long-term monitoring of gas emissions and leachate, as well as environmental management around the site.

Odour complaints

In October 2023, Natural Resources Wales, and to a lesser extent Pembrokeshire County Council (PCC), began receiving a sustained volume of complaints from residents regarding offensive odours associated with the landfill.

In response, Pembrokeshire County Council, Natural Resources Wales, and a multi-agency partnership, including Public Health Wales, initiated a coordinated assessment of ambient air quality.

The aims were to:

Monitor emissions from the landfill potentially affecting local air quality.
Assess the potential public health risks against established health standards and guidelines.
Work collaboratively with the site operators to ensure compliance with environmental objectives.

In May 2024 the site was closed to all waste inputs (except engineering materials) in response to widespread odour complaints from residents and regulatory pressure.

During the closure, RML, with oversite from NRW and the strategic partnership, carried out significant engineering, geotechnical and environmental works, including improved waste-acceptance procedures, stricter testing protocols, and major upgrades to the gas-management infrastructure.

On the 6^th January 2025, Withyhedge reopened. Initially accepting only 'pre-qualifying materials' (i.e., waste streams that have been pre-tested and meet enhanced acceptance criteria).

Monitoring Focus and Methodology

Early in the investigation, hydrogen sulphide (H₂S) was identified as a key pollutant of concern, given its odorous nature and presence as a component of landfill gas. While landfill gas is typically dominated by methane and carbon dioxide, numerous odorous sulphur-based compounds may also be present. H₂S has therefore been used as a surrogate indicator for the presence of landfill gas affecting residential areas.

Monitoring commenced in February 2024, initially conducted by Geotechnology Ltd using static diffusion tubes for H₂S, both on and off-site. Additional methods were later introduced, including Jerome monitors, to allow short-term surveys and reactive monitoring at locations representative of residential exposure.

To provide continuous and independent background monitoring, Ricardo, A global consultancy, who deliver international expertise in air quality modelling, impact assessment, strategies and solutionswas initially jointly commissioned by Pembrokeshire County Council and Natural Resources Wales to install a static H₂S monitoring station, which includes weather monitoring technology, at Spittal School.

This system has enabled consistent, continuous monitoring of ambient air quality in the area, together with data on the influence of meteorological conditions.

RML has committed to ongoing air-quality monitoring both on-site and at the Spittal School location, in order to promote greater transparency with the local community.

Pembrokeshire County Council receives regular reports on air quality from both the Landfill and the Spittal School site, which can be made available upon request.

Registering a complaint for odour nuisance from Withyhedge Landfill Site

Pembrokeshire County Council has established a dedicated email address for complaints relating to odours believed to be from Withyhedge Landfill Site.

Should you wish to submit a complaint please email: complaints.withyhedgelandfill@pembrokeshire.gov.uk

This email address is monitored Monday to Friday, from 9:00am to 4:00pm (excluding bank holidays), Officers from the Pollution Control Team will make every effort to investigate any issues as they are reported.

To ensure that your complaint is dealt with promptly and effectively, we kindly request that you provide the following details, without this information, a thorough investigation may not be possible.

Please ensure your complaint includes:

Your name, address, and contact details (email and telephone number)
A detailed description of your complaint (including accurate dates and times)
The climatic conditions at the time problems were encountered:

Wind strength – still, moderate or strong
Wind direction - from N/E/S/W, etc,
Dry or raining
Warm/cold

The location where the problem was experienced (e.g., outside, inside the house, or in a specific room)
A description of the odour (e.g., sweet, sour, rancid, putrid, etc.)
The impact or effect of the odour (e.g., inability to hang out washing, having to close windows, feeling nauseous, etc.)
Whether the odour is ongoing at the time of your complaint

You may also use log sheets: Record of odour nuisance, which you can record incidents when you are affected by odours from Withyhedge Landfill.

Additionally, please report your complaint to Natural Resources Wales (NRW) by calling their 24-hour telephone number at 0300 065 3000, or by submitting a report online at Natural Resources Wales - Report an incident (opens in new tab). Natural Resources Wales requests that your report includes a description of the odour, the time it was noticed, and how long it lasted.

If you would like further information on Withyhedge Landfill Site please contact:

Pollution Control

Tel: 01437 764551

Email: ContactCentre@pembrokeshire.gov.uk