|
H2O2 |
Chlorine Gas |
| Description |
Hydrogen peroxide (H2O2) is a liquid product supplied as a 35% or 50% solution. It is available in containers of 50 or 300 gallons, or in bulk shipments of 500 - 20,000 gallons. Solid peroxide products (sodium percarbonate and calcium peroxide) are also available. |
Gas chlorine is supplied in pressurized cylinders of 100-lb and one-ton cylinders, and railcars of 10,000 - 20,000 lbs. |
| Control Mechanism(s) |
Oxidizes H2S Retards septicity (adds dissolved oxygen) Promotes bio-oxidation of organic odors |
Oxidizes H2S and organic odors
Inhibits biofilm growth (if overdosed)
|
| Chemical Reaction(s) |
Neutral - Acid pH: H2S + H2O2 --> S + 2 H2O
Alkali: S2- + 2 O2 ----> SO42-
Prevention: 2 H2O2 ----> O2 + 2 H2O
|
H2S + 4 Cl2 + 4 H2O ----> H2SO4 + 8 HCl |
| Dose Ratios (lbs / lb-H2S) |
|
Neutral - Acid |
Alkali |
Prevention |
| Theoretical |
1.0 |
4.0 |
4.0 |
| Practical |
1.2 - 1.5 |
4.5 - 5.0 |
2 - 8 |
|
Theoretical: 8.8
Practical: 8 - 15 |
|
Applications |
Gravity mains (< 3-4 hours retention)Force mains (< 1-2 hours retention)
Terminus of long retention force mainsTreatment plant headworksSolids processingSeptage and leachate
Odor scrubbersPonds and lagoons |
Collection lines (preventative)
Terminus of force mains (curative)
Treatment plant headworks
Recycle streams
Septage and leachate |
|
Advantages |
High selectivity toward H2SAdds dissolved oxygen to retard downstream septicity
Produces no harmful by-productsExtensive history of useIn-line nitrification and BOD reduction possible
Simple feed systemsRelative low feed rates (small storage tanks) |
Fast reaction
Destroys organic odors
Bacteriocidal properties
Reacts with ammonia to retard downstream sulfide generation
Extensive history |
|
Disadvantages |
High dosages are needed for control > 2 hoursOrganic odors require bio-mediated oxidation
Reaction may take several minutes (without catalysis)Oxidizer classification may restrict dosing sites
|
Consumed by ammonia
Major safety and handling issues
Forms chlorinated by-products (VOC emissions)
Chlorine odors if overdosed
High dosages needed to suppress downstream odor generation
Potential for biotreatment inhibition
Corrosive to infrastructure equipment
|
|
Special Notes |
Hydrogen peroxide is one of the more rapidly growing alternatives due to its cost-effectiveness and environmental compatibility. |
Chlorine has rapidly fallen into disfavor for odor control given the safety and handling issues surrounding its transportation and storage (i.e., requires an extensive risk management plan for aggregate quantities > 2000 lbs). |
