New infrastructure project will mitigate sewer gas.

Sewer odor that has occasionally plagued a Sterling Heights neighborhood for many years will be greatly reduced, if not eliminated, by a new underground infrastructure project announced Thursday by the Macomb County Public Works Office.

The project plan involves the construction of an odor control facility along the south side of 15 Mile Road, west of Schoenherr Road, in the ITC Corridor. It is the fifth and final piece of a puzzle involving a series of construction projects in the last six years to mitigate odorous hydrogen sulfide gas that also is highly corrosive to the concrete pipes that carry the raw sewage from hundreds of thousands of residents and businesses.

"The odor has been a periodic problem for years, before I got into office," Public Works Commissioner Candice S. Miller said. "Through a series of infrastructure projects, our team has been able to greatly reduce the sewer gas while lining the interior of the large interceptor pipes to protect them from further severe corrosion that can lead to sewer collapse and sinkholes."

The engineering design and construction of the odor control structure will be funded without an increase in rates to residents. The project is made possible through a $2.5 million supplemental appropriation in the state budget, requested by state Rep. Ron Robinson.

"When I got to Lansing, infrastructure was obviously top of mind," Robinson said. "I have been in conversation with dozens of constituents who have been directly affected by these odors. That is why I fought for this appropriation, and I am proud to deliver the relief they have been asking for."

In recent years, odors have spiked occasionally when the large interceptors up to 11 feet in diameter dozens of feet below the surface have been opened or when flow is stored upstream in the pipes to allow contractors to work inside those pipes. The odor was more noticeable during summer months, when residents were more likely to be outside.

"We were very aware of all the complaints, and we've been working to solve this problem. We sincerely appreciate the patience of residents, businesses and passersby who have put up with the nuisance odor during our critical underground infrastructure projects that take years and millions of dollars to complete," said Miller. "Not tackling these projects eventually would lead to collapses that would be much more disruptive and costly to all ratepayers. We simply cannot afford to have another major sinkhole."

The design of the odor control facility is in the preliminary stage and will continue through the end of 2026 as engineers evaluate the levels of hydrogen sulfide, or H2S, in the upstream areas of the Macomb Interceptor Drain Drainage District (MIDDD) composed of 11 of Macomb County's communities. Final design and construction bids are expected in 2027, with construction tentatively planned to start later that year. It will be built at the confluence of two major sanitary sewer interceptors on the south side of 15 Mile in the ITC Corridor: one that serves the 11 communities in the MIDDD; and one that carries the flow from 12 communities in southeast Oakland County. The combined flows are then carried south through the ITC Corridor to the Great Lakes Water Authority's wastewater treatment facility in Detroit.

"Residents have dealt with these conditions for far too long. It was high time for a change and that is what we delivered," Robinson said.

For now, odors have been temporarily reduced by a mobile odor control unit.