Parameters used:
- An excess of 10% NaOH and NaOCl is assumed for sudden peaks in concentration, upsets or fluctuations in order to stay within the required reductions of H2S and/or odor units.
- The presence of CO2 in atmospheric air (0,03 vol% or 300 ppmv) is NOT taken into account.
- The Na2S that is discharged from Step 1 has to be treated. This is NOT taken into account.
- The program assumes continuous operation, being 8,760 hours per year.
- The hourly costs are multiplied by 8,760 resulting in the annual costs of the chemicals.
How does this work?
The program calculates the annual cost of chemicals required for the removal of H2S and odors from stale air coming from sewers, pump and lift stations, digesters, sludge processing in wastewater treatment plants, etc.
The calculator is based on removal of H2S and odors through caustic (NaOH) and sodium hypochlorite (NaOCl) in a two-step scrubber system:
Step 1:
70% of the H2S is reacts with NaOH to Na2S: 2 NaOH + H2S -> Na2S + 2 H2O;
Step 2:
The remaining 30% of H2S, plus all odorous compounds, reacts with a mixture of NaOH + NaOCl: H2S + 2 NaOH + 4 NaOCl -> Na 2SO4 + 4 NaCl + 2 H2O.
Example 1 - imperial system: (click to show)
The program calculates the annual cost of chemicals required for the removal of H2S and odors from stale air coming from sewers, pump and lift stations, digesters, sludge processing in wastewater treatment plants, etc.
The calculator is based on removal of H2S and odors through caustic (NaOH) and sodium hypochlorite (NaOCl) in a two-step scrubber system:
Step 1:
70% of the H2S is reacts with NaOH to Na2S: 2 NaOH + H2S -> Na2S + 2 H2O;
Step 2:
The remaining 30% of H2S, plus all odorous compounds, reacts with a mixture of NaOH + NaOCl: H2S + 2 NaOH + 4 NaOCl -> Na 2SO4 + 4 NaCl + 2 H2O.
Example 1 - imperial system: (click to show)
From 20,000 cfm of stale air containing 100 ppmv H2S, 99% of the
H2S has to be removed.
Enter this data in the form on the left.
The next information required is the cost of the chemicals. Assume the cost for 100 lbs of a 33% solution of NaOH to be US$ 16 and the cost for 100 lbs of a 12.5% solution NaOCl to be US$ 15. Use these numbers to continue with the program or insert the amount you paid. The program then calculates the annual costs of NaOH plus NaOCl for the required H2S removal.
Example 2 - metric system: (click to show)Enter this data in the form on the left.
The next information required is the cost of the chemicals. Assume the cost for 100 lbs of a 33% solution of NaOH to be US$ 16 and the cost for 100 lbs of a 12.5% solution NaOCl to be US$ 15. Use these numbers to continue with the program or insert the amount you paid. The program then calculates the annual costs of NaOH plus NaOCl for the required H2S removal.
From 30,000 m3/h of stale air containing 150 mg H2S/m3, 99% of
the H2S has to be removed.
Enter this data in the form on the left.
The next information required is the cost of the chemicals. As of July 1st, 2005, the cost for 100 kg of a 33% solution of NaOH was €27,80 and the cost for 100 kg of a 12.5% solution NaOCl was €26,23. Use these numbers to continue with the program or insert the amount you paid. The program then calculates the annual costs of NaOH plus NaOCl for the required H2S removal.
Enter this data in the form on the left.
The next information required is the cost of the chemicals. As of July 1st, 2005, the cost for 100 kg of a 33% solution of NaOH was €27,80 and the cost for 100 kg of a 12.5% solution NaOCl was €26,23. Use these numbers to continue with the program or insert the amount you paid. The program then calculates the annual costs of NaOH plus NaOCl for the required H2S removal.
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