The most common odor ...

The most common odor associated with wastewater collection and treatment is caused by release of hydrogen sulfide gas (H2S). Hydrogen sulfide is produced by anaerobic bacteria that grows beneath the slime layer in wastewater collection systems with long residence time and are corrosive to concrete, steel and equipment such as pumps. Agitation of the wastewater liberates H2S and produces odors at very low ppm levels and deadly at levels above 2000 ppm. Foul odors may also be attributed to oxygen depleted aerobic wastewater processes. One of the least expensive methods to reduce H2S forming bacteria is to elevate the pH/Alkalinity by addition of Magnesium Hydroxide. Elevating the pH/alkalinity from 7 to 8 eliminates H2S and corrosion by 80% and provides alkalinity for nitrification within the treatment plant. Other chemistries such as calcium or sodium nitrate are effective, however they are more expensive.