Todays Hours
Materials Recovery Center
Open Today: 8:00 am - 4:30 pm
View All Hours

All Hours:

  • Monday: Closed
  • Tuesday: Closed
  • Wednesday: 8:00 am - 4:30 pm
  • Thursday: 8:00 am - 4:30 pm
  • Friday: 8:00 am - 4:30 pm
  • Saturday: 8:00 am - 4:30 pm
  • Sunday: Closed

Holidays Closed:

  • New Years Day
  • Martin Luther King Day
  • Presidents Day
  • Memorial Day
  • Juneteenth
  • Independence Day
  • Labor Day
  • Indigenous Peoples Day
  • Veterans Day
  • Thanksgiving and Day After
  • Christmas Eve and Christmas Day

Visit Us:

4587 Ridgeview Rd.
Duluth, MN 55803

Questions?

218-722-3336
Email Us
What We Take
Household Hazardous Waste
Open Today: 8:00 am - 4:30 pm
View All Hours

All Hours:

  • Monday: Closed
  • Tuesday: Closed
  • Wednesday: Closed
  • Thursday: 8:00 am - 4:30 pm
  • Friday: 8:00 am - 4:30 pm
  • Saturday: 8:00 am - 4:30 pm
  • Sunday: Closed

Holidays Closed:

  • New Years Day
  • Martin Luther King Day
  • Presidents Day
  • Memorial Day
  • Juneteenth
  • Independence Day
  • Labor Day
  • Indigenous Peoples Day
  • Veterans Day
  • Thanksgiving and Day After
  • Christmas Eve and Christmas Day

Visit Us:

27th Avenue West & the Waterfront
Duluth, MN 55806

Questions?

218-722-3336
Email Us
What We Take
Yard Waste Compost Site
Closed for the Season
View All Hours

All Hours:

  • Monday: Closed
  • Tuesday: Closed
  • Wednesday: 8:00 am - 4:30 pm
  • Thursday: 8:00 am - 4:30 pm
  • Friday: 8:00 am - 4:30 pm
  • Saturday: 8:00 am - 4:30 pm
  • Sunday: Closed

Holidays Closed:

  • Memorial Day
  • Juneteenth
  • Independence Day
  • Labor Day
  • Indigenous Peoples Day

Visit Us:

27th Av. West & The Waterfront
Duluth, MN 55806

Questions?

218-722-3336
Email Us
What We Take
WLSSD Administration Offices
Open Today: 8:00 am - 4:30 pm
View All Hours

All Hours:

  • Monday: 8:00 am - 4:30 pm
  • Tuesday: 8:00 am - 4:30 pm
  • Wednesday: 8:00 am - 4:30 pm
  • Thursday: 8:00 am - 4:30 pm
  • Friday: 8:00 am - 4:30 pm
  • Saturday: Closed
  • Sunday: Closed

Holidays Closed:

  • New Years Day
  • Martin Luther King Day
  • Presidents Day
  • Memorial Day
  • Juneteenth
  • Independence Day
  • Labor Day
  • Indigenous Peoples Day
  • Veterans Day
  • Thanksgiving and Day After
  • Christmas Day

Visit Us:

2626 Courtland Street
Duluth, MN 55806

Questions?

218-722-3336
Email Us
What We Take

We’re Sniffing Out Wastewater Odors

Al Parrella, who manages our entire wastewater system, starts each work day walking outside to the center of our operation and sniffing the air.

Our employees do the same at pump stations, as well as at our yard- and food-waste site and garbage transfer station.  In fact, all of our office staff also check the air in our parking lots and buildings.

What’s all this sniffing for? We’re trying to smell odors!

All these odor observations are entered into a database, along with any comments from the public.

We clean the region’s wastewater, and we also work constantly to keep our operations as unnoticeable (odor-wise) as possible. We use our observations to be aware of our impact, and also to use the science of odor generation to tweak our operations to reduce our “odor impact” in the surrounding community.

Would you be surprised to hear there’s a science behind odors? Yup, there’s a lot of it, actually.

In our case, the science has to do with the good work done by the bacteria and microbes that break down pollutants and settle out of our wastewater to be turned into fertilizer.

It’s kind of a case of good bacteria doing bad things. When they break down the pollutants, odorants (the name for odor molecules) are released into the air. This is nature’s way of recycling nutrients.

We certainly agree that these odors aren’t what you’d choose to smell. They may sometimes be unpleasant, but they aren’t like odors from some sources that cause long-term physical illness or a direct physical reaction.

WLSSD has done a lot of work over the years to reduce its odors. We’ve tried venting odors in stacks as high as possible and mixing scents to mask odors. Nothing worked all that well until we went back to nature and found a solution.

That solution is called a biofilter. You’ll see them at our plant and our pump stations.

The odorous air from our operations is collected in pipes and then pumped underground to a bed of wood chips. Fungi and other microorganisms that live in those wood chips literally eat the odor out of the air – those odor molecules are like food to these microorganisms.

WLSSD has made a lot of progress through odor monitoring and operational changes. Parrella and a number of us meet regularly to review our observations and comments from the public and our employees.

We know we don’t succeed in preventing odors 100 percent of the time, but we’d like to get there.

So we take our database, look at when we detect odor, and start backtracking our operational data to see if we can tweak the system to find ways to reduce odors, or even predict it.

We may never hit 100 percent odor-free, but we’re doing our best to keep it to a bare minimum.

(Image Credit) We grabbed this off the ‘net to illustrate one of our official sniffing tools, the Nasal Ranger.  This “olfactometer” measures the strength of odors! No kidding, it’s a thing and we are fans. 

Back