New Chemicals v/s Old Standby - Alabama Department of

New Chemicals v/s Old Standby

Jeff Pendergrass, WTPs Superintendent

New Chemicals v/s Old Standby Presentation Outline Coagulation/Clarification Definitions Process Descriptions Commodity Chemicals Specialty Chemicals Case Study Data Plant Trials


Definitions: Valence: The actual number of electrons that an

atom gains, loses, or shares in bonding with one or more atoms is the valence of the atom. If an atom gives away three electrons in a

reaction, then it has a valence of +3 Similarly, if an atom must gain three

electrons to complete a reaction, then it has a valence of -3


Definitions: Isoelectric Point: The pH point of electric neutrality

where the zeta potential has been neutralized and maximum floc formation occurs in the coagulation of water.


Definitions: Colloidal Particles: Finely divided solids that will not

settle-out in water for very long periods of time unless the coagulation-flocculation process is used.


Water Treatment Processes Rapid Mix Coagulation The destabilization and initial

aggregation of colloidal and finely divided and suspended matter by the addition of a floc-forming chemical.

Accomplished primarily through charge neutralization


Coagulation Tiny, negatively charged colloidal

particles repel each other in solution and never collide to form larger, heaver particles

Addition of positively charged Polyaluminun Chloride molecules electrically neutralizes negative charges on colloidal particles

Electrically neutral particles collide with other particles to form larger, heavier particles that will settle from solution


Water Treatment Processes Stability Forces Zeta-Potential The magnitude of the electrical charge

surrounding colloidal particles Hydration The union or chemical combination of

water with other substances


Water Treatment Processes Instability Forces London Vander Waals Force The natural and molecular attraction of

microscopic particles to each other Brownian Movement The random movement of microscopic

particles in a fluid medium such as water


Water Treatment Processes Chemical Coagulants Aluminum Sulfate Ferric Sulfate Ferric Chloride Poly-Iron Chloride (PICl) Poly-Aluminum Chloride (PACl)

1. ACH 2. PACl


Types of Coagulants Aluminum Chlorine (ACS) Polyaluminum Chlorides (PACl) Aluminum Chlorhydrates (ACH) Ferric Sulfate (FES) Ferrous Chloride Ferric Chloride (FEC) Calcium Chloride (CA2CL) Solution Polymers (EPI, Dadmac)


Water Treatment Processes Commodity Chemicals: Aluminum Sulfate Charge Neutralization +3 Valence Relatively Low Molecular Weight pH & Alkalinity Depression

Ferric Sulfate Ferric Chloride


Water Treatment Processes Speciality Chemicals: Poly-Aluminum Chlorides (PACLs)

• PACl • Aluminum Chlorhydrate (ACH) Charge Neutralization +5 to +7 Valence Relatively High Molecular Weight


Water Treatment Processes Chemical Coagulants – Cost Ranking

1. Poly-Aluminum Chlorides 2. Ferric Chloride 3. Ferric Sulfate 4. Aluminum Sulfate



pH Depression

Ferric Chloride Most pH Depression

Ferric Sulfate

Aluminum Sulfate (Alum)

Low Basicity PACl

High Basicity PACl Least pH Depression


What is Poly-Aluminum Chloride (PACl) PACl is a pre-polymerized aluminum coagulant. It lowers the overall pH, like traditional coagulants such as alum or ferric chloride.


Water Treatment Processes Traditional coagulants like Alum or

Ferric Chloride all have a charge of +3; Al3 or Fe3+ (iron). The aluminum in Poly-Aluminum

Chlorides has a higher charge, averaging 5+ to 7+. This means that less aluminum is required

to coagulate a given amount of suspended solids.


Quantifying Active Ingredients Alumina content is expressed as %Al2O3 Typically ranges from 10 to 23.5%

Iron content is expressed as %Fe2O3 Iron Oxide typically ranges up to 20%

Fe2O3 %Me2O3 This specification measures how much Al +

Fe


Basicity The percent substitution of hydroxide (OH)

base for chloride into the aluminum chloride molecule Practical Terms Defines which PACl is present Defines if ACH is present

PACl’s range in basicity from 10 to 83.5% PACl and ACH are very similar products Specific Gravity (SG) goes up as basicity

goes up


Basicity Ranges ACS – 0 to 40% PACl – 10 to 75% ACH – 75 to 83.5%


Poly-Aluminum Chloride advantages over traditional coagulants: Reduces Sludge Production Lower Dosages Lower Alkalinity Consumption Wider working pH range Improved cold-water performance Improved filter operation Faster Floc-Formation Improved Settled & Filtered Turbidities


Sweep Coagulation AKA: Floc lattice Definition: An Overdose/Mechanical removal Traps colloids in precipitated Aluminum Floc. Soluble Aluminum reacts with the natural

alklalinity to aluminum hydroxide Add enough Al/Fe to cause sweep coagulation A normal state of operation, especially for small

colloids CN: PACl/ACH floc remains positively charged


Double Layer Compression The compression of repulsive layers on colloids Allows Van Der Waals Forces to aid in

coagulation Calcium Chloride (CaCl2) Long, but indefinite shelf-life Typically a 10:1 ratio with ACH & CaCl2 CACl2 is relatively in expensive & has a

cationic charge + CaCl2 reduces the amount of primary

coagulant needed and the cost


PAC/ACH ACS: pH: > 1, clear to yellow with iron PACl: pH: 1, < 2.5 is low to high basicity PACl ACH: pH: > 3 Specific Gravity related to Al2O3 and Basicity Specific Gravity rises above 1.3 as basicity

crosses 55%


Jar Test Procedure ALUM Measure Baume Measure Temperature Add Temp Correction factor Prepare a stock solution

PACl Divide desired dosage by the specfic

gravity. Neat dosage on Septums




New Chemicals v/s Old Standby ARAB Water Works (1)

Date: 01/21/2010

Contact: Mike Kirkland

225 rpm for 2 min.

26 rpms for 60 min.

Let settle for 14 min.

Product PPM Sp. Gvy. µL (x2) NTU Winner/Loser

CC-900 20 1.334 30.0 0.612

GC-850 20 1.34 29.9 0.883

GC-650 25 1.18 42.4 2.03

CC-9700 22 1.31 33.6 0.871

CC-9700 A 22 1.3246 32.8 0.757

CC-9700 B 22 1.3475 32.7 0.443

New Chemicals v/s Old Standby ARAB Water Works (2)

Date: 01/21/2010

Contact: Mike Kirkland

225 rpm for 2 min.

26 rpms for 60 min.



CC-901 20 1.33 30.1 0.183

GC-902 20 1.347 29.7 0.481

GC-903 20 1.348 29.7 0.478

CC-904 20 1.335 30.0 0.231

GC-850 20 1.34 29.9 0.174

CC-9700 B 20 1.3475 29.7 0.253

New Chemicals v/s Old Standby Guntersville Date:

01/12/2010 Contact: James Kaan

100 rpm for 1 min.

10 rpms for 10 min.



CC-600 15 1.372 21.9 0.802

GC-700 15 1.195 25.1 1.50

GC-800 15 1.323 22.7 0.524

CC-900 15 1.334 22.5 0.396 CC-451 + Polymer

58 1.31 88.5 1.56

CC-900 + Polymer

20 1.334 30 0.324

New Chemicals v/s Old Standby Piedmont 10/09/09

172 rpm for 1 Min. & 30 Sec.

74 rpms for 13 min. & 4 Sec.



Let settle for 13 min. & 30 Dec.


Alum 13 1.33 9.8 0.778

CC-450 & Additive

12.35 & 0.65 1.33 9.3 1.02

CC-704 10 1.341 7.5 1.25

CC-705 10 1.341 7.5 0.206

CC-9700 10 1.32 7.6 0.147

CC 901 8 1 33 6 0 4 19

New Chemicals v/s Old Standby SCOTTSBORO NSCWTP (79) 01/27/10

100 rpms for 1 min.

15 rpms for 20 min.

Settle for 20 min.


Alum 50 1.33 75.2 0.566 CC-901 25 1.33 37.6 0.153

CC-4864 (95%) & Polydadmac (5%)

20 1.31 30.7 0.268

Alum & EC-409 43 1.31 65.6 0.433

Initial Filtered (NTU) Filter #1 0.093

Filter #2 0.089

Filter #3 0.090

Filter #4 0.078

Initial Settled (NTU) Basin #1 0 67

Basin #2 0 67

New Chemicals v/s Old Standby SCOTTSBORO JWFP (35) 12/10/09

100 rpms for 1 min.

15 rpms for 20 min.

Settle for 20 min.


Alum 40 1.33 60.1 2.50 Alum 45 1.33 67.7 2.70

Alum 50 1.33 75.2 3.13

CC-4864 30 1.31 45.8 1.75 CC-4864 20 1.31 30.5 2.07

CC-4864 15 1.31 22.9 2.22

New Chemicals v/s Old Standby SCOTTSBORO JWFP (35) 02/05/10

211rpms for 1 min.

29 rpms for 23 min.

14 rpms fro 14 min.

Settle for 11 min.


CC-4864 23 1.31 35.1 0.961 CC-9700 23 1.32 34.8 1.68

CC-9700 30 1.32 45.5 1.51

Alum 80 1.33 120.3 2.86 ACTUAL CONTROL CC-4864

23 1.31 N/A 1.05

ACTUAL SETTLED NTU

Basin #1 0.88

Basin #2 0.84

Basin #3 1.20

Basin #4 1.23

AVERAGE 1.05

New Chemicals v/s Old Standby Sheffield 01/27/10

100 rpms for 1 min. ; 90 rpms 1 min.

80 rpms for 2 min.; 70 rpms for 3 min.


25 rpms for 5 min.



CC-700 35 1.195 58.6 2.19

CC-800 26 1.323 39.3 2.16

CC-900 26 1.334 39.0 1.66

CC-300 30 1.343 44.7 0.574

CC-350 30 1.3475 44.5 0.570

CC 9700 30 1 31 45 8 0 494

New Chemicals v/s Old Standby Sheffield 02/18/10

100 rpms for 1 min. ; 90 rpms 1 min.


50 rpms for 5 min.

25 rpms for 5 min.



GC-850 16 1.34 23.9 0.345

CC-9700 B 24 1.3475 35.6 0.324

ALUM 64 1.33 96.2 1.75

CC-9700 24 1.31 36.6 0.280 CC-900 16 1.3 24.1 0.554


Steps to a “New Chemical” Trial Call a good chemical manufacturer or

distributor Establish a reliable calibrated jar test procedure Product selection from PACl, PICl, Ferric &

Alum Blends Petition ADEM for approval of the pilot Includes a Lead & Copper impact letter Obtain a copy of C-of-A and NSF 60 Cert.

Obtain enough product for a 1-week trial


Determine criteria for “successful” trial Settled Turbidity (< WTP’s settled turbidity) Should know the answer in ~6 hours

depending on WTP design Filtered Turbidity (< WTP’s filtered turbidity) Should know the results within 1 – 2 hours

following settling basin transient times (that same day!) If it is really better and going to work, you

will know it when it immediately reaches the filters


Determine criteria for “successful” trial Measure TOC and/or UV-254 content if

desired/ Removal of TOC and/or UV-254 should be

> what the plant is currently producing Measure the finished pH & alkalinity to

determine if pH adjustment or an alkali will be necessary


Common Reason for “failed” PACl trials: Not using a “Calibrated” Jar Test Procedure Inaccurate dosing of Jars (e.g. forgetting to

double the microliters for 2-liter volume jars Not using Wagner® Floc Jars (i.e. using round

cylindrical 1-liter jars) Inconsistent and variable dosing of product due

to low-quality feed pumps for the trial


Common Reason for “failed” PACl trials: Improper dosing of product during plant trial

(e.g. You say you treat 2-MGD (2,800 gpm instantaneously), but you run the plant @ 4-MGD (2,800 gpm instantaneously) for 12 hours to achieve 2-MGD; Results in under dosing the product by half as much as you should Unrealistic Expectations Your own perception of what constitutes

success


Jeff Pendergrass, WTPs Superintendent Questions???

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New Chemicals v/s Old Standby - Alabama Department of