Ferric Chloride negatives:
1. It is an acid adding to wastewater that holds more Hydrogen Sulfide when it is base.
2. It adds Chloride and Electrical Conductivity to any wastewater that is treated with it, meaning all wastewater has more salts in it. For municipalities that reuse water or inject it into groundwater, this means more saltiness to the water.
3. Ferric Chloride adds ten percent or more to the weight of sludges.
4. Large quantities must be added to accomplish the goal of Sulfide reduction.
5. Peroxide must be added as well, doubling the cost, or the wastewater turns to mud for the amount necessary.
6. Ferric ion reduction by Ferrous Sulfide and Sulfur contribute to poorer sludge flocs and therefore more sludge, less density and more water in the sludge.
7. More difficult to de-water sludges.
8. Adds color to water and sludge.
9. No capacity in case of higher loading factor. Any increase in Sulfide concentration cannot be adjusted by additions of more Ferric Chloride partly because you are already adding so much.
10. Hazardous Material –corrosive—classified as an acid.
11. Requires large tanks and specialized handling because it requires large volumes.
12. Limited points of addition of product, because of large volumes needed and limited acesses for materials.
13. Sludging of waste lines.
14. Large addition rates—40mg/l compared to 2-3mg/l Sulfree
15. Stains concrete, plastic and metal.
16. Cannot be sprayed or misted.
17. Causes Corrosion of pipes and equipment
By comparison with Sul-free™:
1. On the base side, instead of adding acid—better for Hydrogen Sulfide control.
2. Sul-free produces no Electrical Conductivity (EC) to downstream wastewater.
3. Sul-free contributes no sludge volume.
4. Low addition rates—5 gallons compared to 120 gallons.
5. Sul-free encourages denser flocks.
6. At use levels, adds no color to the wastewater and no turbidity.
7. Extra capacity in case of higher loading capacity. Can even work catalytically in aerobic systems, allowing removal rates at up to 40 molecules per molecule.
8. No Hazard class. Safe and not regulated.
9. Low addition rates mean small footprint for equipment.
10. Sul-free can be added at any point in the system.
11. Decreases Corrosion.
12. Can be safely sprayed at low concentration to control gaseous emission due to splash transfer and turbulent flow.