Green Bay, Wisconsin:
In 2007 an AO3® ozone system was permanently installed on a force main, which is 8,000 feet in length, 12 inches in diameter, a daily flow rate of 1.0 to 1.5 million gallons, and a retention period of 1.5 hours. Prior to the test the amount of hydrogen sulfide gas at the end of the force main was in excess of 100 ppm.
The AO3® ozone system successfully reduced the amount of H2S to 0 ppm with occasional single digit peaks. The system performed so well that the ozone production was reduced to less than 10% of its capacity. During a few days of the peak summer heat was the ozone production increased. The sulfides in the water were usually 0 mg/liter, but with occasional readings up to 1.0 mg/liter. The dissolved oxygen levels averaged 3.5 ppm
Valley, Nebraska:
During the summer of 2008 a study was conducted in a force main, which is 21,700 feet in length, 16 inches in diameter, a daily flow rate of 333,000 gallons, and a retention period of 18 hours. Prior to the test the amount of hydrogen sulfide gas at the end of the force main peaked at 50 ppm.
Within a couple of days after the start-up of the AO3® system, the H2S levels were at zero. No sulfides were present in the water and the dissolved oxygen content averaged between 2.0 and 3.0 ppm.
Manhattan, Kansas:
During the fall of 2008 a study was conducted in Manhattan on a force main, which is 12,560 feet in length, 8 inches in diameter, a daily flow rate of 67,000 gallons, and a retention period of 12 hours. Prior to the test the amount of hydrogen sulfide gas (H2S) at the end of the force main was in excess of 200 ppm. The amount of sulfides in the water was 5.3 mg/liter, and the dissolved oxygen was 0.41 to 1.8 ppm.
The AO3® ozone system successfully reduced the amount of H2S gas to 0 ppm with an occasional peak of 2.0 ppm. The sulfides in the water were eliminated, and the dissolved oxygen content was above 25.0 ppm.