Something is in the air that’s leaving residents holding their breath.
Intermittently, the area along 4 Avenue SW has been plagued by a strong odour emanating from the sewage lines along it.
The Town of Drumheller is taking action to clear the air. Within the month, the Town hopes to meet with, what they believe to be the ultimate source of the smell, the Royal Tyrrell Museum.
“Working together we’ll pick a solution. It will never completely eliminate the problem, but we want to reduce it to a level that’s acceptable to the people living in the area,” said CAO Ray Romanetz at the January 7 meeting of the Committee of the Whole.
The Town of Drumheller believes that in times of low usage, the sewage from the museum is left to stagnate, at which time hydrogen sulfide, what residents are smelling, is produced. The gas then travels down the sewer line and is released into the air.
Last year in June, the Town replaced a section of the sewer line along 4 Avenue SW that was reverse graded. Prior to the replacement, sewage had to flow uphill, which resulted in times when it would cease to flow and therefore begin to release hydrogen sulfide.
“It’s certainly improved the flow of sewage along the line. There were also a number of steps taken along with that, such as improvements to the forced main and a relief valve. All of this has, to some degree, reduced the hydrogen sulfide problem,” said Romanetz.
The Town also embarked on a pilot project to add products to the sewage to help reduce the smell. Results indicated the desired effect, but the cost is thought to be too high.
“It worked, but, from our standpoint, was too costly. It might be something we approach from a seasonal basis,” said Al Kendrick, Director of Infrastructure Services.
The presence of hydrogen sulfide can be smelled at extremely low concentrations (0.00047 ppm) and smells like rotten eggs. As the concentration increases, so do the effects. Eye irritation can begin to occur between 10 to 20 ppm. Eye damage between 50 to 100 ppm.
Sense of smell can disappear starting at 100 ppm. A pulmonary edema, and possibly death, can occur above 320 ppm. Lethal concentration begins at 800 ppm. A single breath of concentrations over 1,000 ppm can cause an immediate collapse with loss of breathing.
Concentrations measured during the study in Nacmine on average saw concentrations of 2 ppm.
Aside from health, the Town is concerned constant exposure to hydrogen sulfide will erode steel and concrete.
“In very low concentrations, people will pick up the odour. Even at concentrations as low as that, there are all kinds of issues relating to erosion...it completely breaks down concrete,” said Romanetz.
As a temporary solution to combat the smell, the Town has sealed manholes along 4 Avenue SW.
The same concerns about erosion warrant prompt action according to Councillor Doug Stanford.
“I don’t know if we should leave them closed for too long. It’s attacking the vent lines in these houses. It will corrode,” said Stanford. “This should be a high priority.”
If all goes well, the Town hopes to meet with the museum and come up with a solution.
“Now is the time to do a detailed review and come up with a long term solution,” said Romanetz.
