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!