Sodium BiSulfite Pump Design

[madhusmile]

I am working on a Sodium BiSulfite Pump Skid design for dechlorination and as per my research, for every 1 mg/L of total chlroine, 1.63 mg/L of SBS is needed to reduce total chlorine residual to Zero.

Assuming I have 700 gpm of flow with 1 mg/L of total chlorine, what would be my pump rate for SBS which is available in aqueous solution.

Somewhere, I have seen an example and trying to figure out how they came up with this one.

At max designed flow rate of 5 MGD, 27.2 gal/day of SBS is required for every 1 mg/L of total chlorine. How did they cam up with this using above concentration levels?

Can anyone help me?

Thanks

 

[orenda1168]

Madhusmile:

700 GPM = 2,650 liters/min flow.

At 1 mg/l chlorine = 2,650 mg/min chlorine.

2,650 mg/min chlorine X 1.63 = 4,320 mg/min requirement for sodium bisulfite.

Based on your pump's capacity, choose a mid-range discharge volume and develop a sodium bisulfite-water solution that will deliver 4,320 mg/min to the 700 gpm water flow at that pump output.

Orenda

 

[kenvlach]

From "At max designed flow rate of 5 MGD, 27.2 gal/day of SBS is required for every 1 mg/L of total chlorine. How did they cam up with this using above concentration levels?"

From this info & knowing the 1.63 SBS/chlorine (by weight) ratio, calculate the concentration of the SBS treatment solution:

At a max 5 MGD, per 1 mg chlorine/Liter (3.7853 mg chlorine/gallon), need 27.2 gal/day of SBS solution.
So 18,926,500 mg chlorine requires x 1.63 (SBS/chlorine) = 30,850,195 mg SBS, or 30,850 grams SBS.
Since the SBS is dissolved in 27.2 gallons of water, its concentration is 30,850 grams/27.2 gallons

Concentration of SBS treatment solution
= 1134 grams/gallon
= 2.5 pounds SBS/gallon
= 300 grams/Liter.

Now, back to first part of question.
As 700 gpm @ 1 mg chlorine/L requires 4.319 grams SBS/min,
the required SBS treatment solution is
(4.319 grams SBS/min)/(300 grams SBS/L) = 0.0144 L/min (14.4 mls/min).

You could use a peristaltic pump of 25 mls/min capacity (1.5 L/hr).
Or, for more uniform dosing, dilute the SBS solution by a factor of 10, to 30 grams/Liter, giving a higher flow requirement of 144 mls/min. Then use an electric, diapragm-type metering pump of capacity 300 mls/min (18 Liters/hr (4.76 gallons/hr).

Ken

 

[quark]

At max designed flow rate of 5 MGD, 27.2 gal/day of SBS is required for every 1 mg/L of total chlorine. How did they cam up with this using above concentration levels?

It depends upon what concentration SMBS they are using. 27.2gpd is 102.96 lpd. As per your testing result(1.63ppm of SMBS for 1 ppm of chlorine), it comes to be 30.85 kgs/day.

If the SMBS concentration is 30%w/v then 102.96 lpd is 0.3*102.96 = 30.88 kgs/day. However, commercially available concentration, in India, is about 65%w/v. So, it is better to check at what concentration the solution is prepared.