Ex: Think total hardness is 200ppm. Total treated water requirement is 5000L/day.
Then how calculated the
a) Softener vessel size?
b) Required resin volume?
c) Salt regeneration time?
d) Dosage of salt?
Assuming you are referring to permanent hardness as CaCO3. Ion exchange resins have a capacity of approximately 1 equivalent per liter of resin.
Your requirement is small, you may want to consider a cartridge type system. If you do a regular column, you can buy in the market a 6" X 48" column. Fill it to about 30" height. This gives you about 14 liters of resin. You will exhaust about 4-5 liters per day. Therefore the column will last you 3 days before regeneration. Best if you contact a water softener dealer and get a self regeneration valve made by companies like Fleck, Autotrol. Minimum service flow rate will have to be 200-250 liters per hour. Most of the softener valves will be configured to automatically backwash, draw a saturated salt solution from a tank in which the water level is below the solid salt level, and rinse. If you wish to do this manually, you will need to make 30 liters of 10% NaCl (or KCl if you want the hardness to be replaced by K ions) and pump it through the column at 50 or so liters per hour. Before the brine pumping, you will need to reverse flow for 10 mins or so at 230 LPH. After the brine, you will need to rinse at same flow rate with water, then a fast flow rate of 560 LPH. If possible, use soft water for rinsing. Hope this helps......
Ideally, a water softener should be sized so that it does not regenerate any more often that every three days (wastes water and salt), nor go longer than 14 days before regenerating (can cause compacting of resin, and fouling with sediment or iron). 7 days between regenerations is probably best - especially if iron is present. For the majority of homes, our 1 cubic foot unit is more than enough capacity. There are conditions that would create a need for a larger unit: larger family (6 or more) and/or very hard water (over 15 grains). Use the following formula to calculate the proper size: 1. Multiply the number of people in your family times 70 (gallons of water used per day, national average). 2. Multiply the answer by your water hardness in grains per gallon (to convert mg/l or ppm to grains, divide by 17.1). If iron is present, add 5 grains for every ppm (mg/l) of iron (iron MUST be dissolved iron - it appears clear from the tap but leaves reddish-brown stains). 3. This is your "grains per day" number. Divide this number into each of the softener capacities until you find the best size.
You can find additional data on:
http://www.pure-earth.com/softcalc.html
Hello,
check this website: http://www.water-chemistry.in/2011/04/how-to-calculate-resin-capacity-for-softener-softening-plant/
And you can also use purolite calculator: https://www.purolite.com/calculators/index
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