By Violet Li
Surrounding communities of Stevensons Brothers Industries (SBI) landfill have been disgusted by the latest surge of a reportedly ‘rotten egg’ odour, but the cause is yet to be identified.
On the first weekend of February, the Environment Protection Authority Victoria (EPA) received 73 odour incident reports in the vicinity and started the investigation.
When inquired, a spokesperson from EPA said it received a notifiable incident report from SBI on Saturday 3 February that there had been a potential failure of odour management infrastructure at the site and that several actions had been taken to fix the problem.
“However, those actions did not immediately rectify the problem and we received community reports complaining of a rotten egg smell,” they said.
“Our landfill experts are conducting odour surveillance around the facility and in the community. That is continuing until we are satisfied that SBI has the problem under control.”
A different story seems to have been presented at an SBI Community Consultative Committee (CCC) meeting held on Tuesday 6 February, where representatives from SBI reportedly stated that the hydrogen sulphide (H2S) monitors on site did not show any sign of detection, according to an update from the CCC on the meeting.
After conducting odour surveys onsite and offsite, SBI believed the odour could not be attributed to the landfill and suggested the origin was the sheep from the property directly next door to them, according to the CCC’s update.
SBI stated on its website that five full-time SBI employees had had their noses calibrated in accordance with EPA guidelines.
CCC member and Brookland Greens resident Nick Ter-kuile, present at the meeting, said it was the first time the community had ever heard about sheep.
“This [the landfill odour incident] has been going on for 18 months. So I don’t think anybody could believe the sheep was true,” he said.
“Residents have smelled the odour constantly for the last two years. We know what it is better than any others.
“Most people and I will take what EPA says, not the SBI because it’ll be like believing the person had broken into your house saying that they didn’t do it.”
While the mention of sheep seemed quite ‘laughable’ to the community, Mr Ter-kuile pointed out that no authority had been able to identify what the issue was.
Representatives from SBI told the meeting that they reported to the EPA – on the day of the most odour complaints – they changed a carbon filter in their leachate storage tank headspace as a precautionary action.
An update from SBI on its website on Saturday 10 February noted that ‘identifying alternate odour sources to that of SBI was not done to shift blame’.
“These are qualitative observations by suitably qualified and trained personnel,” the update wrote.
A week following the untraceable odour, EPA attended the landfill site on Saturday 10 February after a new wave of community odour reports.
EPA officers detected landfill odour at an offsite location approximately 500 metres from the closest edge of the landfill, an onsite location approximately 100 metres west of the site entrance along Ballarto Road, and onsite leachate storage tanks, which were approximately 180 meters from the site entrance.
A H2S parts per billion (ppb) monitor located in the northern boundaries of the site recorded an average of 0.3 ppb during 9-10 February with a maximum of 9 ppb at around 4am on Friday 9 February.
According to EPA NSW, about half of people can smell H2S at a concentration of around 8 ppb. However, the odour sensitivity varies among individuals as some people can smell it at 0.5 ppb.
“Exposure to these low concentrations of H2S may cause irritation to the eyes, nose or throat, and difficulties in breathing in people with asthma,” the EPA website writes.
“Repeated exposures at these levels can also understandably cause anxiety and distress and result in indirect symptoms such as headaches and nausea.”
The source of the odour has also not been identified, but SBI noted in a February website update that a treatment system for the leachate storage tank was ‘now being investigated for points of weakness in the treatment train’ and ‘a long meteorological is being sought to eliminate interference by meteorological fluctuations’.
SBI identified the leachate storage tank as a potential offsite odour source in April 2023 and accordingly upgraded the extraction system on its headspace.
The odour continued to upset the community, with 69 new air pollution reports coming up from 12 to 16 February.
SBI believed that about 45 per cent of the reports could not be attributed to the landfill based on the wind direction.
“Statistically, given the high percentage of reports that cannot be attributed to SBI based on wind direction alone, rationalises that the percentage of false reporting within the remaining reports, to be reasonably high as well,” its update wrote.
A maximum H2S of 21 ppb was detected on the morning of Tuesday 13 February at the northern boundary of the site at around 5.30am.
The same monitor showed 9 ppb at 4.55am, 5 ppb at 6:32am, and 3 ppb at 7.42am on the morning of Friday 16 February.
No trace of H2S was detected at other times in the week.
A new H2S scrubber is due to go online on 1 March and a new flare on 15 March subject to the approvals being granted by Energy Safe Victoria.
