Two Harbors to conduct smoke test on sewer
The city of Two Harbors will be performing a smoke test on the sanitary sewer system throughout the entire town July 19-21.
The work will occur between the hours of 8 a.m. and 4 p.m., and the crews will go block by block starting with the downtown area. The harmless smoke will be blown into the sanitary sewer system and city crews will be in the area to look for spots where the smoke is coming out of the ground, building foundations, manholes, catch basins, downspouts or entering homes. Smoke will not enter a home or business if it is properly plumbed, vented and water traps contain water.
"We are going to purposely send smoke, forced in with a fan, and we're going to drive around and look for these areas," said Luke Heikkila, water and wastewater plant supervisor. "If homeowners have dry traps or have improper connections in their basements, they'll see smoke in their house."
In preparation for this test the city recommends that residents who have bathroom or plumbing fixtures that are not used or are seldom used should fill the traps by running water in the fixtures the day before the scheduled smoke test. Water can evaporate from unused plumbing fixtures and sewer gases can enter the home. Water should be added on a monthly basis thereafter in order to prevent sewer gas from entering the home or office.
The smoke used is a non-toxic substance that is harmless to humans, pets, food and material items. If smoke does enter the building, it will clear in a few minutes with proper ventilation. As a precaution, open the bathroom windows for ventilation and close the door, in case smoke does enter the bathroom.
If smoke does enter a home or business, the occupants should contact a representative of the smoke testing crew by walking outside and locating one. Crews will be in marked city trucks as well as on four-wheelers with vests on. Though, Paul Johnson, city gas, water and sewer superintendent, said if someone isn't sure if the smoke is from the test or a fire, they should leave the building and call 911.
This test will allow city crews to figure out where clean rain or groundwater is entering the sanitary sewer system. Heikkila said they conservatively estimate that about 150 million gallons of water leaves the wastewater treatment plant, is used by homeowners in Two Harbors and comes back into the treatment plant, but the Two Harbors wastewater treatment plant saw approximately 302 million gallons of wastewater last year.
"So if we are pumping 150 million out and treating 302 million, we are seeing double due to I&I. And that's a conservative number," he said.
The hope, Johnson said, is by identifying these areas where inflow and infiltration, or I&I, are entering the sanitary sewer system, the city can reduce the I&I by 10 to 20 percent.
"It's important to do this test to find areas where stormwater is leaching into the city sanitary sewer system," Johnson said. "If we don't, costs could go up for utility customers."
Anyone with questions about the test, or any other concerns, should feel free to ask a crew member, visit twoharborsmn.gov or contact the Sewer Distribution Department at (218) 834-8812. If it rains during the three day period, the crews plan on continuing the testing starting on July 24.