Ground & Water Engineers and Engineering Technicians visited the site. Bulk gas analysis did not identify any carbon monoxide, hydrogen sulphide, or methane during the visits. Oxygen was recorded between 23.10 – 23.60%, nitrogen was recorded between 75.8-76.3% with trace amounts of carbon dioxide (<0.05%). The results of the bulk gas analysis were generally consistent with atmospheric gas concentrations. The results did not indicate the presence of landfill gases within any of the rooms tested. When the indoor levels of CO2 were compared against typical outdoor atmospheric conditions small increases in carbon dioxide levels were noted. This was expected and consistent with carbon dioxide levels within occupied buildings.

 

Gas Canister Analysis from the kitchen cupboard of both properties revealed a wide range of determinants, likely to have a relatively innocuous source related to the recent construction and commissioning of the buildings. It is thought that the various solvents, adhesives, fillers, plasters and paints associated with the construction of a new build development account for most of the VOC, SVOC and TIC compounds encountered within the kitchen areas on-site. Further to this there were also some compounds related to cleaning chemicals.

So far there was still no clear indication of the source of the smell.

The residents insisted they noted the eggy smells intermittently and had detected methane as LEL on analysers. During Ground & Water’s visits no smells were noted nor was methane detected within the canisters. Given methane is odourless it was concluded that this smell was likely to be related to hydrogen sulphide. This indicated sewer gas to be the potential source opposed to gas from the old landfill beneath the site.

Following Ground & Water’s advice to the client, the foul drainage network around the properties was investigated, and failures were found. The foul drainage pipes were fixed or upgraded, and the smells have not occurred since.

Thanks to the tenacity and diligence of the Ground & Water team, which despite its own findings trusted and followed up on the property owners’ experiences, an escalating smelly crisis was averted.