Joint statement from the Hafod Landfill Stakeholder Group
A further positive meeting to discuss progress at Hafod landfill site took place Friday, November 7th.
Senior representatives of Enovert, Rhos Community Council, Ruabon Community Council, Wrexham Council and Natural Resources Wales (NRW) met to discuss the site in Johnstown, which has been at the centre of odour-concerns from local residents.
Enovert explained more recent mitigations to minimise odour from its operations including further permanent capping works undertaken, the installation of a new gas engine and the preparation of an area which will be temporarily capped in the next few weeks.
Capping is the process of sealing the surface of the landfill with 1m of engineered clay (permanent capping) or 1mm of plastic liner. Both types of capping reduce emissions of landfill gas, aids gas extraction and minimises water from entering the waste mass.
The gas engine uses landfill gas as a fuel to produce renewable electricity. The new engine is capable of running continuously collecting gas 24/7 preventing odours.
Data related to the most recent monitoring continues to show the recorded concentrations of hydrogen sulphide, the chemical compound recognised as the ‘rotten egg’ odour within landfill gas, are well below 1 parts per billion (ppb) at all locations including the community centre. 1ppb is recognised as the lowest health criteria value by Public Health Wales.
The AQ Mesh pods have now been calibrated by the manufacturer, the manufacturer has determined scaling factors to improve accuracy, these scaling factors have now been applied to all of the data set from April 2025 onwards.
The scaling factors were determined by calibrating the AQMesh pods against similar pods and other monitoring devices being used by another landfill site in Wales and was considered necessary by the manufacture of the pod.
AQ mesh pods are designed to log real-time measurements of Hydrogen sulphide that record average readings every 30 minutes based on readings taken every 10 seconds.
The results will be updated and presented within the next summary report, which will be placed on Natural Resources Wales Citizen Space. The scaled results indicate that around 90% of the data from all of the pods (on-site and off-site) is typically <5ppb with the average value <1ppb, which is in good agreement with other fixed monitoring data (such as from the diffusion tube monitoring).
The report also highlights that hydrogen sulphide is being detected from a range of compass directions, indicating that there are potentially multiple sources of hydrogen sulphide in the site’s locality.
As part of the ongoing collaboration Natural resources Wales (NRW) carried out investigations into a particular offsite odour source. A source was identified on the Vauxhall Industrial Estate, and action was taken which eliminated the odour.
It was noted that complaints from the public have dropped significantly in the past few months, and it is believed that this is due to improvements onsite as well as identifying other sources of odour not related to the Hafod landfill site.
Further scheduled works onsite in the New Year, specifically proposed drilling of new gas wells, may lead to a higher than usual risk of odour from these works. Enovert will provide notice of the works in advance and will use all appropriate measure to control the drilling activities.
Further information can be found on the Natural Resources Wales website.
Summary of actions since last meeting
- Further permanent onsite capping
- Installation of gas engine
- preparation of area to be temporarily capped
- Calibration of AQ mesh pods
- Source of offsite odour identified, and action taken
- Further onsite work identified for new year
- Ongoing site monitoring
- Ongoing offsite monitoring
- Further meeting between Hafod Landfill Stakeholder group with a commitment to maintain collaboration and keep public informed
Number of complaints from January 2025 to November 2025 are as follows:
| Jan | Feb | Mar | April | May | June | July | Aug | Sept | Oct | Nov |
| 262 | 84 | 50 | 31 | 12 | 9 | 40 | 35 | 25 | 13 | 15 |
