Humboldt residents: Pray for dry weather.
The City of Humboldt has contracted Saskatoon-based Dairyland Agro Supply Ltd. to clean out the lagoon's sludge build-up.
The process is expected to begin within the next couple of weeks and Peter Bergquist, director of planning and engineering for the City, said that rainy weather would delay the process.
Why the hurry?
Well, in addition to the foul-smelling odour from the lagoon that everyone would like remedied, the material removed from the lagoon will be spread onto farmland to be used as fertilizer.
Which means they have to get this done before the farmers start seeding, typically by the end of May.
"It'll be a tight squeeze but if this dry weather keeps up, then it won't be a problem," Bergquist said. If the project does end up getting delayed for some reason, the City said it will look at its option to clean the lagoon in the fall.
The lagoon began emitting an odour last summer, with residents all over town complaining of the putrid stench.
Bergquist said lagoon sludge takes about 10 years to build up before it needs to be pumped out and heat, which breaks down the material faster, only hastens the odour issue.
Humboldt's lagoon is made up of two primary cells (ponds), the first one being an anaerobic cell. Raw sewage is pumped into the first cell, where the bacteria begin breaking down the matter.
"The first cell, the anaerobic one, is smelly just by its nature because it creates sulfuric sulfate. So the odour residents are smelling is not just from the sludge but from the cell itself," Bergquist said.
Normally this wouldn't be happening but when sludge builds up over time, the treatment isn't as effective as it could be.
Anything left over moves onto the second cell, where the remaining water is released into smaller storage cells. It's then flushed twice a year into Stoney Lake.
"When we release it, we add a chemical additive to it that pulls out any remaining heavy materials, and of course we have to test it to comply with quality control," Bergquist explained.
For the sludge build- up, the company hired will set up pumps that stir all the material up and then suck it out, injecting it onto nearby fields.
"The farmers love this because it acts like fertilizer," Bergquist said.
The sludge then has to dry before the farmers can start seeding.
The whole cleaning process will take about a week or two and Bergquist said the City is in constant contact with Dairyland Agro, who are currently on another job site in Saskatoon, as to when they're arriving.
The City said it did review chemical options to combat the lagoon's odour in the meantime but the size of the lagoon means any chemicals used in it would require a "crazy amount" of money Bergquist said.
As Bergquist mentioned, sludge is mostly decomposed human waste and paper, although it's really anything thrown down the drain, "Which can be a scary thought," laughed Bergquist.
Some chemicals, like gasoline and motor oil, get flushed down as well. Where this may pose a problem for other city's lagoon systems, the types of cells Humboldt have are best for commercial development, so oils and hydraulic material don't cause an issue. However, it's never recommended to dispose of chemicals that way.
Bergquist said the last time Humboldt's lagoon was cleaned out was 12 years ago.
