**Hydrogen sulfide concentrations exceeding 7 to 10 ppm can be removed by injecting an oxidizing chemical such as household bleach followed up by filtration. The oxidizing chemical should enter the water upstream from the storage or mixing tank to provide at least 30-45 minutes of contact time between the chemical and water. The length of length of the holding time is a function of the chemical dosage, tank configuration and water temperature. Sulfur particles can then be removed using a sediment filter and the excess chlorine can be removed by activated carbon filtration.
If test results indicate that bacterial contamination is occurring, shock chlorination or disinfection is the most widely suggested method for initial treatment. Shock chlorination (disinfection) is the one-time introduction of a strong solution into the entire water distribution system (well, pump, distribution pipeline, etc.)
When to Shock Disinfect the Well:
Shock chlorination (disinfection) is recommended when lab results indicate a presence of bacteria upon completion of a new well or after pump replacement or repair, when the distribution system is opened for repairs or maintenance, following contamination by flood water, to control iron and sulfur bacteria.
Shock chlorination (disinfection) is recommended in these circumstances to ensure that bacterial contamination is controlled.
This system should be used where low to moderate ferrous (dissolved) iron or hydrogen sulfide contamination is known. This filter is most effective where iron and hydrogen sulfide levels are less than 5 ppm. Best removal rates are achieved where pH is between 6.5 and 8.5 and where water contains some dissolved oxygen.