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H2O2 |
Sodium Chlorite |
| 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 chlorite (NaClO2) is supplied as a 25% solution in either 55-gallon drums, 300-gallon totes, or 4,000 gallon tank trucks.
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| Control Mechanism(s) |
Oxidizes H2S Retards septicity (adds dissolved oxygen) Promotes bio-oxidation of organic odors |
Oxidizes H2S and organic odors
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| Chemical Reaction(s) |
Neutral - Acid pH: H2S + H2O2 --> S + 2 H2O
Alkali: S2- + 2 O2 ----> SO42-
Prevention: 2 H2O2 ----> O2 + 2 H2O
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Neutral - Acid pH:
2 H2S + NaClO2 ----> 2 S + HCl + NaOH + H2O
Alkali: S2- + 2 NaClO2 ----> SO42- + 2 NaCl |
| Dose Ratios (lbs NO3 per lb-H2S) |
|
Neutral - Acid |
Alkali |
Prevention |
| Theoretical |
1.0 |
4.0 |
4.0 |
| Practical |
1.2 - 1.5 |
4.5 - 5.0 |
2 - 8 |
|
|
Neutral - Acid pH |
Alkali |
| Theoretical |
3.0 |
3.0 |
| Practical |
3 - 10 |
3 - 5 |
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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 |
Terminus of collection lines
Septage and leachate
Solids processing units
Ponds and lagoons
Recycle streams
Precursor for chlorine dioxide generation
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|
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) |
Simple feed systems
Relatively quick reaction
No harmful by-products are formed
Efficient reaction with H2S
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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
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Limited industry experience
Moderate to high cost
Best applied as a curative (to destroy odors already present)
Oxidizer rating may restrict dose 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. |
Sodium chlorite use has greater utility for solids processing where its quick reaction with organic odors is valued.
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