Page 345 - Water and wastewater engineering

8-14 WATER AND WASTEWATER ENGINEERING

TABLE 8-2
Typical ranges for design data and criteria for strong acid cation and strong base anion resins
Strong acid Strong base
Parameter cation resin anion resin Unit
Exchange capacity 3.6–5.5 1.8–2.0 meq/g as CaCO 3
1.6–2.2 0.8–1.4 meq/mL as CaCO 3
a
Operating capacity 50–70 40–60 % of exchange capacity
Moisture content 40–80 35–80 %
3
Shipping weight (moist) 640–930 670–720 kg/m
Screen size 16 50 16 50
3 3
Service flow rate 200–2000 200–2000 m /d · m of resin
8–40 8–40 BV/h
3 2
Surface loading rate 400–800 400–800 m /d · m or m/d
3 2
Backwash rate 12–20 5–7.5 m /h · m or m/h
Backwash duration 5–15 5–20 min
Bed expansion 50 50–75 %
Regenerant NaCl NaCl
Regenerant concentration 5–10 2–15 %
3
Regenerant dose 80–320 80–320 kg NaCl/m of resin
2
3
Regeneration flow rate 60–120 60–120 m /d · m or m/d
2–5 2–5 BV/h
Rinse volume 2–5 2–10 BV
pH range 0–14 0–14 units

Max. operating temp. 140 OH form 60; C

C form 100
Turbidity limit 5 5 NTU
Iron limit 5 0.1 mg/L as Fe
Total Fe Mn 0.3 0.3 mg/L
Chlorine limit 1.0 0.1 mg/L of Cl 2
a
Operating capacity depends on the method of regeneration and amount of regenerant applied.
Sources: Clifford, 1999; GLUMRB, 2003; MWH, 2005.

from the exchange capacity in that it is a measure of the actual performance of the resin under
a defined set of conditions such as the raw water composition, empty-bed contact time (EBCT)
or service flow rate (SFR), and degree of regeneration. The operating capacity is always less
than the advertised exchange capacity because of incomplete regeneration, early leakage (break-
through) that causes termination of the operational cycle to meet design limits, and efficiency of
regeneration (measured as eq NaCl/eq CaCO 3 ).
Small laboratory columns (1.0 to 5.0 cm inside diameter) have been effective in analyzing
alternative resins. These columns can be scaled directly to full scale design if the loading rate
and EBCT are the same. Because the resin beads are small compared to the column diameter,
the error due to channeling of the water down the walls is small. The hydraulics of full scale
operation cannot be modeled by these small scale columns (MWH, 2005).