Modeling and Mitigating Hydrogen Sulfide in Municipal Interceptors from a High Strength, High Temperature Industrial Wastewater

ABSTRACT

In 2008, the Green Bay (Wisconsin) Metropolitan Sewerage District acquired the De Pere Wastewater Treatment Facility and interceptors from the City of De Pere. Two of those interceptors received wastewater from paper mills exhibiting high biochemical oxygen demand and high temperatures. Mill wastewater contributed 80 percent of the total interceptor flows, making conditions highly conducive to sulfide generation. Control measures were necessary to prevent unacceptable hydrogen sulfide concentrations in the interceptors. A computer model was used, along with 7 months of collected field data, to assess the effectiveness of treatment alternatives. The calibrated sulfide generation factor in the model was lower but within a magnitude of the recommended value by Pomeroy-Parkhurst. To eliminate vapor phase hydrogen sulfide issues in one of the interceptors, a force main was installed to allow wastewater to be pumped from one of the mills directly to the treatment plant. A biological slime layer that formed in the force main appeared to inhibit sulfide generation or transfer of sulfide to the wastewater. The slime layer resulted in elevated force main pressures and lower flow rates. Hydrogen peroxide addition successfully reduced the slime layer. The two mills discharging to the second interceptor employed liquid phase chemical treatment using ferrous chloride and hydrogen peroxide to mitigate sulfide generation.

KEYWORDS: odor, hydrogen sulfide, paper mill, interceptor…

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