EVERETT – John Berg thinks Everett’s Smith Island sewer plant has never smelled so good.

The E. Grand Avenue resident’s nose knows that hasn’t always been the case, especially on hot, windless summer days.

That’s when the rotten-egg smell of hydrogen sulfide and other odors would waft across the Snohomish River into his neighborhood.

“It was bad,” he said, standing on the front porch of his house overlooking the river and Cascade Mountains on a chilly evening last week. “If we left windows open, the stuff would get trapped inside.”

During the warm months of August and September this year, he didn’t notice any bad smells from the plant.

That’s likely because a change in the way the city feeds oxygen into lagoon water, where bacteria break down organic matter.

New aerators are adding more oxygen to the water to prevent the growth of bugs that produce the stench at the plant.

Now, other steps designed to reduce odor are about to go online.

“That’s our everyday working goal,” said Robert Waddle, operations superintendent for the treatment plant. “We’re taking all the right steps to make it smell better.”

A nearly-completed $41 million project by Portland’s Hoffman Construction Co. includes placing aluminum lids atop giant tanks that process tens of millions of gallons of waste per day.

City spokeswoman Kate Reardon said having a bad-smelling sewer plant on the city’s northern end doesn’t do much to bolster Everett’s image.

Drivers on I-5 have sometimes called the city to complain.

“Oftentimes the only exposure is driving through on I-5,” Reardon said.

The city hired a San Francisco-based firm last week for $250,000 to work on a new identity strategy. City officials say they are trying to find ways to combat lingering stereotypes of Everett as a smelly industrial town.

The new lids are designed to trap stinky air. Before it is released, it is blown through fiberglass pipes into “bio filters,” which are basically a few large areas with bark and wood chips.

At that point, the odor-creating compounds are supposed to be absorbed into the chips.

The city is also adding a covered tank that will shift the first stage of treatment for most of the sewage from outdoor open-air lagoons.

Existing tanks also have been expanded and capped.

Last month, Hoffman contractors hoisted two 11-ton geodesic domes over “trickling filters” which will soon process a combined 21 million gallons of sewage a day. The domes are now visible from nearby I-5.

“The trickling filters have a very distinct smell to them,” said Waddle. He said the odor may remind some of a “musty dog.”

“It’s not something you’ll want to smell everyday.”

Now the filters are capped, the odor should be eliminated.

Still, “I’ll never be able to say we’ll eliminate odors 100 percent,” Waddle said.

In addition to reducing odor, the project also includes expanding the mechanical plant’s capacity to process waste from 16.5 million gallons to 21 million gallons per day.

Overall, including the outdoor lagoon system, which is used for treating overflow, the plant will be able to process an average of 36.5 million gallons per day.

Other improvements include disinfecting effluent with liquid chlorine, rather that chlorine gas.

The city has tried to flush foul odor from the sewer plant for years with little success.

One attempt saw public works employees dump $235,000 worth of Byo-Gon PX-109, an elixir made of kelp and other organic material, into sewer lines.

In the mid-1990s Everett spent $1.43 million on a project that included collecting gases and treating them with a filter.

It also covered four giant screw pumps that move water from underground pipes to treatment ponds.

In 1998 the city received 150 complaints about odor from the plant. That number has dwindled to just a few a year, Reardon said.

Reporter David Chircop: 425-339-3429 or dchircop@heraldnet.com.