Odour Monitoring in Calne

This week we have continued to have officers out monitoring for odour in the community, including over the bank holiday weekend. We have also attended during the early hours of the morning between 2:30am-:4:00am to ensure we in the area when odour is being noticed.

During some of our recent odour rounds we have been able to detect landfill gas odour in some residential areas, however this has been generally transient and at low levels of intensity.Environment Agency staff odour monitoring during the early hours However, we appreciate that odour can enter homes and buildings causing it to remain for longer. The UKHSA advises closing your windows when outdoor odour levels are high or if you are downwind and opening them when the air clears.

While our ambient air monitoring station continues to monitor and record data 24/7, we are scaling back our proactive odour monitoring in the community over the next couple of weeks.

We are doing this because:

• We have seen a recent reduction in odour reports
• When detected, our officers have rated recent odour from Lower Compton landfill as low intensity and transient in residential areas
• Weather forecasts for the next week indicate a return to prevailing winds, meaning any emissions from Lower Compton are likely to disperse over less populated areas. We maintain the ability to attend reactively and will review the requirement for further proactive monitoring in June, as work continues to cap the main source of odour on site.

Once the engineering works are complete, we will carry out a period of daily odour monitoring to confirm that the works have minimised odour from Lower Compton landfill.

Hills capping and site update

We are closely monitoring the capping works at Hills. We routinely attend site to ensure works are progressing to time and standard. This week, contractors on site have completed the placement of the 300mm deep subsoil “regulating layer” over the area to be capped. This layer has been tested for shear strength and trial pits dug to confirm it is a minimum of 300mm deep. Work is now underway placing the first of four 250mm layers of clay to form the cap, with most of the permanent and temporary capping areas now covered.

We expect odour levels to reduce once capping works are complete and will carry out further proactive odour monitoring to verify this.

UKHSA data monitoring

As previously reported, we have provided UKHSA with an initial set of data for health analysis. We are now in the process of providing further data to UKHSA that contains more detailed data to enable a public health risk assessment to be made. We will share information on when the UKHSA public health risk assessment is available as soon as we are able to.