ORGANICSHow do we catch and kill
them ?
Organics 2
Where do organics come from ? What are they ? How to measure them ? What do they do to a demin water plant ? How is resin fouling affecting plant operation ? What resins to use ? How to prevent resin fouling ? How to restore fouled resins ?
ORGANICS AND ION EXCHANGE RESINS
Organics 3
ORIGIN OF ORGANIC MATTER
Organics are mainly found in surface water (rivers, lakes)
Vegetals Animals
Domestic waste Industrial waste
Organics 4
Principle• Oxidise with potassium permanganate• Boil in acidic conditions• Titrate excess KMnO4
Procedure• See notes
TOC vs COD• TOC measured as mg of Carbon• COD measured as Potassium
Permanganate consumptionVery rough thumb rule:
• 1 mg/L TOC ~ 5.5 mg/L as KMnO4
MEASUREMENT (KMnO4 method)
There is no direct relation between KMnO4 and TOC measurement
Organics 5
We don’t guarantee a given degree of removalResins are there to exchange ions, not organics
• (in industrial water treatment)
Usual degree of organic reductionWBA 50 to 90 %SBA polystyrenic 40 to 90 %SBA polyacrylic 50 to 90 %
REMOVAL FROM WATER
Organics 6
ELUTION OF ORGANICS (from resin)
WBA 90 to 100 % SBA type 1 50 to 90 % SBA type 2 60 to 95 % SBA Acryl 90 to 100 %
When elution (during regeneration) is less than 100 %, organics accumulate on resin
This is Resin Fouling
When elution (during regeneration) is less than 100 %, organics accumulate on resin
This is Resin Fouling
Organics 7
Example of fouling
Water with 5 mg/L as KMnO4
SBA resin type 2 Run length 100 Bed volumes
(e.g. 1000 m3, 100 m3/h)Organic load 100 x 5
= 500 mg KMnO4 per L resin Organic removal 50 %
5 mg/L in ——> 2.5 mg/L out250 mg organics are picked up by resin in each run
Elution 80 %Only 0.8 x 250 = 200 mg are removed from resin50 mg/L accumulate on resin in each run
After 200 cycles, resin contains 10 g/L of organics
5 mg/L
2.5 mg/L
Organics 8
Humic acid
Humic acid structure proposed by Dragunov
CO O H
CH 2 CH 2 CH 2
CH 2
NHC
CH 2 CH 2 CH 2
C H O6 11 3
C H O N8 18 3
CH CH
O O
O O O
O
O O H
O H
N NCH CH
O CH 3
O H
O
O O H
O
O
C H O N = 118064 68 24 4
A typical decay product or building block is gallic acid:
C O O H
O H
O H
H O
Organics 9
NATURAL ORGANIC ACID (partial structure)
Molecular mass500 - 30 000
OOO
O
CH 2
CH 2
C H 2
N H 2
CH 2
CH 2
CH 3
O -
O C
O -OC
O -
O C
Organics 10
STRONGLY BASIC RESINS (partial structure)
Polystyrenic Polyacrylic
CH 2
C H 2
C H 2
C H 3
N + N +
N +
C H 2 C H 2
CH 2
C H 3 C H 3
C H 3
C H 3 C H 3
C H 3
C H 3 C H 3
C H 2 C H 2
CH 2
C H 2
N+
C H 2
C H 2
C H 2
C H
N HC =O
CH 3
C H 3C H 3
C C
H H
N +
C H 2
C H 2
C H 2
N HC =O
C H 3
CH 3C H 3
N +
C H 2
CH 2
C H 2
N HC =O
C H 3
C H 3C H 3
Organics 11
CH 2
CH 2
CH 2
CH 3
N + N +
N+
CH 2 CH 2
C H 2
CH 3 CH 3
CH 3
CH 3 CH 3
CH 3
CH 3 CH 3
OOO
O
CH 2
CH 2
CH 2
NH 2
CH 2
C H 2
C H 3
O -
O C
O -OC
O -OC
ELECTROVALENT BONDING
Attraction between
cation & anionAnion resin
Organic acid
Organics 12
VAN DER WAALS BONDING
Attraction betweenaromatic rings
OOO
O
C H 2
C H 2
C H 2
N H 2
C H 2
C H 2
C H 3
O -O -
O
OC
C
O -OC
C H 2
C H 2 C H 2C H 3
N +
N+N + CH 2
C H 2
C H 2
C H 3C H 3
C H 3
C H 3C H 3
C H 3
C H 3
C H 3
Anion resin
Organic acid
Organics 13
OOO
O
C H 2
C H 2
C H 2
N H 2
C H 2
C H 2
C H 3
O -O -
O
OC
C
O -OC
C H 2
C H 2 C H 2C H 3
N +
N +N + C H 2
C H 2
C H 2
C H 3C H 3
C H 3
C H 3
C H 3
C H 3
C H 3
C H 3
C H 2
C H 2 C H 2C H 3
N +
N +N + C H 2
C H 2
C H 2
C H 3C H 3
C H 3
C H 3
C H 3
C H 3
C H 3
C H 3
ADSORPTION OF THE ORGANIC ACID
Combination of ionic and Van der Waals attraction
Polystyreneanion resin
Organicacid
Polystyreneanion resin
Organics 14
FOULING OF RESINS
Regeneration breaks the ionic bondsIt doesn't break the Van der Waals bonds
Acrylic resins are not aromatic !Van der Waals forces are therefore weak
Acrylic resins don't get fouledUse Amberlite IRA458 or IRA478
Organics 15
HOW DOES FOULING GET NOTICED ?
NaOH is absorbed inside resin(on – COOH groups)
Rinse is long Na leakage increases SiO2 leakage increases
Capacity decreases Moisture content decreases
Problems in plant operation
SBA resin rinse
Bedvolumes
µS/c
m0
102030405060
0 2 4 6 8 10 12 14 16 18 20
Long rinse
Organics 16
FOULING INDEX
Example 1Degassed water, 6 meq/L Tot Anions
12 mg/L KMnO4
• N = 12/6 = 2 Moderate
Example 2Undegassed, thin water, 1.5 meq/L
12 mg/L KMnO4
• N= 12/1.5 = 8 Highly fouling
Example 3High TDS water, 15 meq/L, 3 mg/L KMnO4
• N= 3/15 = 0.2 Not fouling
N = OM (mg/L as KMnO4)
Total Anions (meq/L)
Organics 17
ORGANIC LOAD
Example 16 meq/L Tot Anions, 12 mg/L KMnO4
• Assume a capacity of 0.6 eq/L for SBA alone• BV treated = 1000 x 0.6/6 = 100• Organic load = 100 x 12 mg = 1.2 g/LR as KMnO4
Example 2Thin water, 1.5 meq/L, 12 mg/L KMnO4
• Assume a capacity of 0.6 eq/L for SBA alone• BV treated = 1000 x 0.6/1.5 = 400• Organic load = 400 x 12 mg = 4.8 g/LR as KMnO4
The definition of
Organic Load:
Quantity of organics going
through the resinNot
quantity removed by
the resin
The definition of
Organic Load:
Quantity of organics going
through the resinNot
quantity removed by
the resin
Organics 18
New ExampleHigh TDS water, 15 meq/L, 30 mg/L KMnO4
Combination WBA / SBAWBA cap 1.0 eq/L, ionic load 10 meq/L
——> 100 BV treated
SBA cap 0.5 eq/L, ionic load 5 meq/L——> 100 BV treated
Each litre of WBA gets 24 mg x 100 BV = 2.4 g as KMnO4
WBA picks up about 60% of organicslets through 40%
SBA gets 0.4 x 30 = 12 mg/LH2O
Each litre of SBA gets 12 mg x 100 BV = 1.2 g as KMnO4
ORGANIC LOAD (cont.)
2.5 mg/L
Org 12 mg/LIons 5 meq/L
WBA SBA
Org 30 mg/LIons 15 meq/L
Cap 1.0 eq/L Cap 0.5 eq/L
Organics 19
RESISTANCE TO FOULING
Resin N max max load g/LR as KMnO4
Amberjet 4200 Cl 3 2Amberjet 4400 Cl 2 1Amberjet 4600 Cl 6 4Amberlite IRA402 Cl 3 2Amberlite IRA405 Cl 10 5Amberlite IRA410 Cl 6 4Amberlite IRA458 Cl 15 8Amberlite IRA478RF Cl 15 12Amberlite IRA900 Cl 6 3Amberlite IRA910 Cl 10 4Amberlite IRA96 12 12Amberlite IRA67 20 25Amberlite IRA70RF 18 20
Resin N max max load g/LR as KMnO4
Amberjet 4200 Cl 3 2Amberjet 4400 Cl 2 1Amberjet 4600 Cl 6 4Amberlite IRA402 Cl 3 2Amberlite IRA405 Cl 10 5Amberlite IRA410 Cl 6 4Amberlite IRA458 Cl 15 8Amberlite IRA478RF Cl 15 12Amberlite IRA900 Cl 6 3Amberlite IRA910 Cl 10 4Amberlite IRA96 12 12Amberlite IRA67 20 25Amberlite IRA70RF 18 20
Organics 20
Organic SCAVENGER (organic trap)
Is used to protect demin plantReduction of organic load on WBA and SBA
Today, not much usedAcrylic resins used instead in the demin line
SCAV SAC SBADEG
Organics 21
SCAVENGER RESINS
Resin choicePolystyrenic macroporous
• Amberlite IRA900 Cl
Polyacrylic macroporous• Amberlite IRA958 Cl
Regeneration2 BV of a 10% NaCl + 2% NaOH solutionSizing :
• So that organic load is about 10 g/L as KMnO4
10 to 30 BV/h Efficiency
Organic removal 50 to 90%
Composition of feed water to demin plant is
changed (more Cl, less HCO3 and
SO4)
Composition of feed water to demin plant is
changed (more Cl, less HCO3 and
SO4)
Organics 22
WBA resins help !
Combine WBA macroporous resin with SBA
WBA protects SBA
Combine styrenic and acrylic matrixe.g. IRA96 + IRA458
3-compartment Amberpack® anion column
Compartment 1 designed as “integrated organic trap”.Use reverse flow regeneration for WBA
WBA 1
WBA 2
SBA
IRA96RF
IRA96RF
IRA458RF
Amberlite
Organics 23
DETERGENTS
Detergents are particularly harmful to anion resinsThey cause irreversible fouling
(they can practically not be removed)
Example : ABS (Alkylbenzene sulphonates)
Best bet : Acrylics (again !)
Organics 24
HOW TO LIMIT FOULING
Good pre-treatmentFlocculationChlorinationScavenger resins
Membrane filtrationUltrafiltrationReverse osmosis
Good resin selectionAcrylic SBAUse a WBA to protect SBA
Limit loadingShort runsUse more resin (“dilution”)
Regenerate more efficientlyIncrease NaOH levelHot NaOH (type 1 only!)
Regular de-fouling treatment
(see next slide)
Organics 25
RESTORING RESIN QUALITY
Best cure : alkaline brine treatmentSolution of 10 % NaCl + 2 % NaOHSee details in the notes
Acid treatment(useful when iron is complexed with organics)
Treatment with 10% HClSee details in the notes
After treatment,
check resin rinse
After treatment,
check resin rinse
Organics 26
Thank you!
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