Odor/Corrosion Control With Nitra-Nox For Hydrogen Sulfide Prevention

In the case of this project in Indiana, sulfur compounds were the predominant odor constituent and are characterized by a strong, pungent odor that can be identified from great distances. The concentration of sulfur compounds are dependent upon several factors such as temperature, weather, wind flow, microorganism count and residence time in treatment process. Some odorous compounds are considered offensive even at low concentrations. For example, ammonia at 2-5 ppm and mercaptans as low as 1 ppm.

Aulick looked at the following lift station data points to determine Nitra-Nox feed rate:

• Lift Station A: Average daily flow = 145,920 GPD. Lift Station A pumps 7,284’ through an 8” force main and 5,263’ through a 16” force main. Based on the average daily flow and size/length of the force main, the average retention time for Lift Station A force main is 3 hours in the 8” line and 9 hours in the 16” line. The total average retention time before discharging is 12 hours. Based on these insights, the estimated Nitra-Nox feed rate at Lift Station A was 34 gallons per day.
• Lift Station B: average daily flow = 300,000 GPD. Lift Station B pumps 0.25 miles through a 12” force main and 5 miles through an 18” force main. Based on the average daily flow and size/length of the force main, the average retention time for Lift Station B force main is 0.62 hours in the 12” line and 28 hours in the 18” line. The total average retention time before discharging to the wastewater treatment plant is 28.6 hours. Based on this data, the estimated Nitra-Nox feed rate at Lift Station B was 112 gallons per day.