The malodorous marauder stalking downtown Columbus could be gone as early as November.

The malodorous marauder stalking downtown Columbus could be gone as early as November.

The city of Columbus soon will begin testing special air-cleansing systems next month to get rid of foul odor wafting from sewer grates in the central city and surrounding neighborhoods.

The longstanding problem is the Olentangy-Scioto Interceptor Sewer, also known as OSIS, which runs through downtown.

It is a combined sewer system, meaning both sanitary and stormwater are part in one system. There are many more openings in the line, which allows gas to escape.

The odor-mitigation plan is part of a much larger project known as OARS - Olentangy-Scioto Interceptor Sewer Augmentation Relief Sewer -- a $342 million wet-weather management agreement with the Ohio EPA that reduces sewer overflows.

To help alleviate the odor and overflow problems, the city is installing a 200-foot-deep, 23,300-foot-long trunk line to provide relief to the sewer line from the Arena District to the Jackson Pike wastewater treatment facility.

The total project should be completed by 2015.

Part of the project involves two underground odor-control facilities, resembling giant mulched beds.

One is at Neil Avenue and Vine Street in the Arena District and the other is on Short Street on the edge of the Whittier Peninsula.

Giant fans pull the smelly gas through a series of metal grates layered with lava rock, pine bark and bacteria, cleansing the air and leaving it virtually odor-free on the other side.

"It's tried-and-true biotechnology at its finest," said George Zonders, spokesman for the public utilities department. "We're using it in other areas. It does a really good job."

Zonders said the problem is more noticeable during hot weather when there has been little rain.

Complaints are common and the odor can make it uncomfortable for people drawn to new downtown attractions, such as Columbus Commons and the Scioto Mile, Zonders said.

"The fact that we're trying to draw and maintain businesses downtown, the fact that we're trying to draw citizens and maintain residences downtown, it's a significant problem," he said.

The fix can't come soon enough for Dave Patel, manager of C-Town Market at the corner of Town and Fourth streets.

At times, the smell is so overpowering, customers don't want to sit on the patio.

"I am very happy that the city is taking care of it," he said. "The smell is an issue. If they put the filters in everything will be nice."