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Rydall WO reduces BOD, FOG, COD, TDS & H2S in sewer system!






The city of Oconto, Wisconsin was looking to reduce corrosion from high levels of H2S at one of its sewer line lift stations, as well as odors that resulted in several complaints from residents. The system was also experiencing high and fluctuating levels of BOD, FOG, COD and TDS. Three sanitary districts feed into this sewer line through several miles of enclosed plastic sewer pipe with approximately 33,000 gallons of residential sewage flowing through this particular monitoring station.
In addition to monitoring daily H2S levels using an Oda-Log monitoring system, the city was using Bioxide to control odors and corrosion. Anywhere from 2 gallons to as much as 15 gallons of Bioxide were added to the system per day, but was not effectively solving the issues.

RYDALL WO Solution

After understanding the science and benefits behind RYDALL WO, the city agreed to use the non-active biocatalyst per our recommendation to reduce the odors, corrosion and contaminants. We recommended injecting RYDALL WO at 100 ppm (3.3 gallons per day) with a metering pump at a lift station approximately 7 miles upstream from the problematic area. This allowed approximately 2.5 days of retention time for the RYDALL WO  to work. 
Along with the city’s continuous monitoring of H2S levels, samples of the wastewater were also taken weekly from each location and tested by our team for BOD, FOG, COD and TDS levels (samples of the wastewater prior to treatment were also taken for control purposes).
Over the course of the next 90 days, our tests showed average levels of BOD, FOG, COD and TDS decreased significantly, as shown below:
  • BOD levels decreased by 28%!
  • FOG levels decreased by 67%!
  • COD levels decreased by 30%!
  • TDS  levels decreased by 23%!
Compared to the city’s data from a similar time frame in 2012 when Bioxide was used, the amount of H2S released during RYDALL WO  treatment decreased by more than 50%! Within the first couple weeks, odors from the problematic lift station were drastically reduced and there were no odor complaints from the surrounding community. Also, the city saw a significant reduction in corrosion at the site. Components that were normally replaced due to corrosion from H2S, did not have to be replaced during the trial. 
This RYDALL WO  trial recently concluded in September and is currently being evaluated by the city of Oconto.

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