|
H2O2 |
Sodium Hypochlorite |
| 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. |
Sodium hypochlorite (NaOCl) may be considered a liquid form of chlorine, kept in solution by the incorporation of caustic (NaOH). It is supplied as 12 - 15% solution in containers of 1 to 300 gallons, and in bulk quantities of 4,000 - 20,000 gallons.
Depending on ambient temperature, it has a half-life (in storage) of 2 - 6 months. |
| 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 NaOCl ----> H2SO4 + 4 NaCl |
| 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 lbs NaOCl per lb-Sulfide
Practical: 8 - 15 lbs NaOCl per lb-Sulfide |
|
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 (to prevent downstream odors)
Terminus of force mains (to destroy pre-existing odors)
Treatment plant headworks
Recycle streams
Septage and leachate
Small systems (HTH tablets) |
|
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
Inhibits biofilm growth
Reacts with ammonia to provide residual H2S control
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 in the water
Has a relatively short shelf-life
Forms chlorinated by-products (VOC emissions)
Chlorine odors are emitted if overdosed
High dosages are needed to suppress downstream odor generation
Potential exists for biotreatment inhibition (from overdosing)
Hazardous properties may restrict dosing sites
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Special Notes |
Hydrogen peroxide is one of the more rapidly growing alternatives due to its cost-effectiveness and environmental compatibility. |
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