Perchlorate Ion Exchange Process using Weak Base ... - Purolite
Perchlorate Ion Exchange Process using Weak Base ... - Purolite
Perchlorate Ion Exchange Process using Weak Base ... - Purolite
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Objective<br />
Demonstrate a novel, regenerable, perchlorate-selective ion exchange process that:<br />
Greatly minimizes waste volume<br />
Permits efficient waste reuse or disposal<br />
Reduces treatment costs compared to state-of-the-art<br />
regenerable & non-regenerable processes<br />
Approach<br />
Screened ion exchange resins and technologies<br />
Selected weak base anion (WBA) technology<br />
Developed an efficient, economical WBA treatment process<br />
Demonstrated WBA treatment process at Redstone Arsenal<br />
WBA <strong>Ion</strong> <strong>Exchange</strong><br />
<strong>Ion</strong> exchange and regeneration processes are accomplished by controlling pH<br />
At high pH, WBA resin functional groups are in the non-ionized, free-base form<br />
At low pH, functional groups are ionized enabling anion exchange<br />
WBA resin in free-base form (R-NH 2 ) is ionized (R-NH 3 + ) by protonating with acid (H + ):<br />
R-NH 2 + H + ➞ R-NH 3<br />
+<br />
Protonated resin removes anions (A - ) from aqueous streams:<br />
R-NH 3<br />
+<br />
+ A - ➞ R-NH 3 -A<br />
Spent resin (R-NH 3 -A) is regenerated by neutralizing with caustic (NaOH),<br />
which liberates anions and returns resin to the free-base form:<br />
R-NH 3 -A + Na + OH - ➞ R-NH 2 + HOH + Na + A -<br />
WBA <strong>Ion</strong> <strong>Exchange</strong> <strong>Process</strong> (Patent Pending)<br />
Pretreatment<br />
Reduce pH<br />
Acid<br />
Treated<br />
Water<br />
Contaminated<br />
Water<br />
<strong>Ion</strong> <strong>Exchange</strong><br />
Conventional<br />
Lead-Lag Equipment<br />
Lead <strong>Ion</strong><br />
<strong>Exchange</strong><br />
Vessel<br />
Post Treatment<br />
Restore pH<br />
and Alkalinity<br />
Lag <strong>Ion</strong><br />
<strong>Exchange</strong><br />
Vessel<br />
Bypass<br />
Caustic<br />
Degassing<br />
CO2 Removal<br />
Key Features:<br />
Conventional lead-lag<br />
configuration<br />
System pressure<br />
keeps dissolved<br />
CO 2 in solution<br />
Single pumping operation<br />
Stripping excess CO 2<br />
before neutralization<br />
minimizes post<br />
treatment cost<br />
Demonstration Site: Redstone Arsenal, AL<br />
Selected Well RS498<br />
6-inch Extraction well<br />
<strong>Perchlorate</strong>: 1500 to 2000 ppb<br />
Bicarbonate: 150 ppm<br />
Nitrate: 4 ppm<br />
Sulfate: 3 ppm<br />
Chloride: 4 ppm<br />
TCE: 3100 ppb<br />
Isotherm Results<br />
ClO 4 <strong>Exchange</strong>d on Resin (meq/L)<br />
110<br />
100<br />
90<br />
80<br />
70<br />
60<br />
<strong>Perchlorate</strong> concentration:<br />
600 to 1500 ppb<br />
WBA resin demonstrated:<br />
<strong>Perchlorate</strong> selectivity<br />
High exchange capacity<br />
y = 45.7x + 30.4<br />
50<br />
0.50 0.70 0.90 1.10 1.30 1.50<br />
ClO4 in Solution (mg/L)<br />
Pilot System Design & Operation<br />
Conventional lead-lag configuration<br />
Integrated pre- and post-treatment<br />
24 hr/day – 7 day/week operation<br />
2-inch diameter ion exchange columns<br />
Macroporus polystyrene divinylbenzene WBA resin<br />
36-inch bed depth<br />
12 to 24 bed volumes/hr treatment rate<br />
1.5 to 3 gpm/ft 3 of resin<br />
6 to 12 gallons/hour<br />
Demonstration<br />
began 6/23/05<br />
Demonstration<br />
completed 10/7/05<br />
15 week test<br />
5 test scenarios<br />
Pilot Breakthrough Curves<br />
Consistent with isotherm prediction<br />
<strong>Perchlorate</strong> removal to < MDL<br />
Effective over range of<br />
treatment rates<br />
Performance unaffected by<br />
regeneration<br />
<strong>Perchlorate</strong> (ug/L)<br />
500<br />
400<br />
300<br />
200<br />
100<br />
24 BV/Hour<br />
18 BV/Hour<br />
12 BV/Hour<br />
Lag Columns<br />
0<br />
0 1000 2000 3000 4000 5000 6000 7000 8000<br />
Water Treated (Bed Volumes)<br />
WBA Regeneration<br />
Successfully demonstrated three approaches<br />
Single-pass regeneration & protonation<br />
Batch regeneration & protonation<br />
Batch, “zero-discharge” regeneration<br />
& protonation<br />
Near 100% perchlorate removal<br />
Resin performance not affected by regeneration<br />
No perchlorate "leakage"<br />
No loss of treatment capacity<br />
Zero-Discharge Regeneration<br />
Scavenge spent regenerating and rinse<br />
solutions with strong base anion resin<br />
Reuse or discharge treated<br />
regenerating and rinse solutions<br />
O&M Cost: $5/acre-foot<br />
for drinking water (50 ppb)<br />
Biodegradation of<br />
Regenerating Solution<br />
Use existing CSTR technology<br />
Neutralize & dilute by ~50%<br />
Discharge treated regenerating<br />
solution to sewer<br />
O&M Cost: $2/kg of perchlorate<br />
Conclusion & Comparative Cost<br />
WBA IX process is:<br />
<strong>Perchlorate</strong>-selective<br />
High capacity<br />
Regenerable<br />
50 times more efficient<br />
than Cl - regeneration<br />
Zero discharge for<br />
drinking water<br />
Treatment Cost<br />
per Acre-Foot<br />
$400<br />
$300<br />
$200<br />
$100<br />
Low O&M cost: $50 to $100 per acre-foot<br />
Single-Pass Regeneration<br />
Clean<br />
Water<br />
Regen<br />
Tank<br />
Clean<br />
Water<br />
Caustic<br />
<strong>Perchlorate</strong><br />
Biodegradation<br />
System<br />
Herington, Kansas<br />
Caustic<br />
Clean<br />
Water<br />
Caustic<br />
Regen Rinse<br />
Tank<br />
Regen<br />
Tank<br />
Batch Regeneration<br />
Regen<br />
Tank<br />
Regenerant Scavenging<br />
Feed<br />
Pump<br />
Conventional<br />
NaCl Brine<br />
Regenerable<br />
<strong>Ion</strong><br />
<strong>Exchange</strong><br />
Vessel<br />
Clean<br />
Regen<br />
Water<br />
Rinse Scavenging<br />
Feed<br />
Pump<br />
Feed<br />
Pump<br />
Feed<br />
Pump<br />
<strong>Ion</strong><br />
<strong>Exchange</strong><br />
Vessel<br />
Clean<br />
Rinse<br />
Water<br />
<strong>Perchlorate</strong> Removal from Drinking Water<br />
Single-Use<br />
Disposable<br />
<strong>Ion</strong><br />
<strong>Exchange</strong><br />
Vessel<br />
<strong>Ion</strong><br />
<strong>Exchange</strong><br />
Vessel<br />
WBA Resin<br />
Regenerable<br />
Scavenger<br />
Resin<br />
Vessels<br />
Scavenger<br />
Resin<br />
Vessels
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