Wastewater Treatment Plant Odor Fix Could Cost $2 Million

 03/17/2017 - 02:23

When Saline City Council last met, it learned that fixing the Rec Center roof would cost $2 million. When city council sits down Monday, it will hear a recommendation to spend nearly $2 million to solve the odor problems at the wastewater treatment plant.

Webster Environmental Associates, of Louisville, Ky., has completed its $100,000 study of the odors emanating from the wastewater treatment plant. WEA is recommending a second test in warm weather in order to validate or revise the preliminary findings. Based on the results of the first test, WEA recommends a plan that will cost the city $1.93 million plus an additional $92,000 a year in operations and maintenance. On the other hand, the new odor removal system would save the city about $40,000 a year on the chemicals and water the city uses now.

According to WEA, this option would treat odors from all the significant sources at the wastewater treatment plant and reduce odors by 99 percent.

Such a project would last seven to 12 months.

The study found that:

  • Relative to other plants tested by WEA, odors from the Saline plant were found to be in the low to moderate range. The increase in odors may be a result of aging odor control systems.
  • The nearest neighbors to the plant are adjacent to the plant’s fence line. Models predict neighbors might detect odors up to 2,000 events a year.
  • Odors of the residents who called to complain about the plant lived within a mile and on the east side (down wind) of the plant.
  • The Duall chemical scrubber was found to be the largest contributor to off-site odor emissions, contributing up to 60 percent of the total plant emissions. The scrubber is 20-years old and nearing the end of its useful life.
  • The 17-year-old ERA Tech scrubber leaks and could expose workers to corrosive chemicals. The manufacturer is no longer in business.
  • The septage receiving facility was not in operation during testing. However the facility does not employ any type of odor control. When in operation, it is predicted to generate significant odors.

WEA’s fix would be to demolish the existing chemical scrubbers and replace them with two dual media, radial flow carbon adsorption vessels, which would treat all significant odors at the plant. WEA also recommends more efficient covers on equipment, new ductwork to route foul air to the new system, and a new carbon adsorption odor system at the south side pumping station to treat foul air from the wet well.

According to models provided by WEA, the new system would drastically decrease the level and frequency of odor emissions.

The models are based on cold weather testing and have been altered to factor in warm weather conditions, which generally increase odor problems.

City council’s work session begins at 6 p.m.

Tran Longmoore
Tran Longmoore is owner of The Saline Post. Email him at tran@thesalinepost.com or call him at 734-272-6294

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