BOUNTIFUL—Ever wonder what happens after you flush a toilet? Most of us take it for granted that someone is making sure that is treated and safely disposed of. But who does that? At South Davis Sewer District, they take the job very seriously, using high-tech processes to clean wastewater in the five cities they serve.

“The district was formed in 1959,” said General Manager, Matt Myers. “The Clean Water Act was created by the federal government in 1972. There was a treatment plant push before that.”

There were two main objectives, he said. “The first was to collect waste without a disease-causing agent. In the 1800s they stopped seeing cholera infection that we don’t have to deal with now through hand washing and a sanitary sewer system. The second was the rest of the battle of it going to a safe place in a form that is safe.”

The South Davis Sewer District processing plant from above. Photo by Roger V. Tuttle.

The sewer main line is in the roadway to the curb and gutter and lateral service from the home to the road is the resident’s responsibility, he said. “The main branch in the road we maintain but we will come out and line it to your foundation for the cost of materials if you qualify. It’s usually older sections of town. It could cost the resident $20,000 to replace. The service lateral lining program has been successful.”

Myers said crews go into each manhole in the district’s service area with robot cameras to check the sewer lines. “Bountiful sewer was built in the 40s before the treatment plant. Some of those sewer lines are 80 plus years old. We’re going in to check the integrity of those and take a meaningful look for problems.”

It’s like tree trunk branches that go into larger lines, he said. “We get through those systems as much as possible. Crews are out every day cameraing and doing target cleaning. Right after it’s been cleaned you can see a crack pop out more visibly.”

There are a few things the public does that make their job difficult, said Myers. “We’re always fighting flushable wipes. They’re really not flushable. Toilet paper will dissolve. Wipes never dissolve. When people use a lot of those it can create a basement backup and the floor drain will bubble up sewage.”

Restaurants should clean and scrape everything into the trash, he said. “It’s a better spot for it. Most have a dedicated grease trap. Garbage disposals are fine, they are designed to break food up – just keep wipes out.”

Some district facts:

• 372.41 miles of sewer pipe

• 97,252 people served

• Two treatment plants (north and south plants)

• North Plant treats 8-10 million gallons per day (South treats 3-4 million gallons per day)

• Annual operating budget of around $8 million

There are nine steps in the South Davis Sewer treatment process:

• Headworks – screening, pumping

• Grit removal – remove sand

• Primary sedimentation – settle solids 

• Trickling filtration – turn dissolved and non-settling pollutants into settleable cell mass

• Secondary sedimentation – settle solids

• Disinfection – add/remove chlorine

• Solids thickening (sedimentation)

• Solids anaerobic digestion – reduce solids (like a stomach)

• Solids dewatering – sun-drying solids

“There’s a lot more technical stuff than you realize,” said Myers. “For public health we’re environmentally responsible to treat it.”

There are $60 million of improvements that have to be made, he said. “There are federal regulations we have to abide by. We’ll have to bond to make the improvements so rates will probably go up.”

It won’t just be the $60 million, said Myers. “Ongoing expenses will go up as well. Construction and inflation hit us hard. It’s hard because we’ve always prided ourselves on running economically.”