Yong Kim, Ph.D.UGSI Chemical Feed, Inc.

Impact of Upgraded Polymer Activation on Sludge Treatment at Water Treatment Plant

Presentation Overview – Polymer Activation

2

Effect of Dilution Water Chemistry

Effect of Mixing Profile/Strategy

Two-stage mixing: high energy, then low energy mixing

Two-step dilution: primary mixing, then post-dilution

Case 1 - Dry Polymer Mixing System

Fairfield-Suisun Sewer District, CA

Case 2 - Emulsion Polymer System

Water Treatment Plant, PA

Effect of Dilution Water Quality

Ionic strength (Hardness): multi-valent ion hinders polymer activation

- Soft water helps polymer molecules fully-extend faster

- Hardness over 400 ppm may need softener

Oxidizer (chlorine): chlorine attacks/breaks polymer chains

- Should be less than 3 ppm

- Caution in using recycled water for polymer mixing

Temperature*: higher temperature, better polymer activation

- Water below 40 oF may need water heater

- Water over 100 oF may damage polymer chains

pH: negligible effect within pH 3 - 10

3

*David Oerke, 20% less polymer with warm water, 40% more polymer with 140F sludge, Residuals and Biosolids (2014)

Effect of Dilution Water Hardness

0

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600

800

1000

1200

1400

0 50 100 200 400

Hardness, mg/L

Soft water helps polymer chains to be fully extended

emulsion polymer, 0.5%

Kim, Y.H., Coagulants and Flocculants: Theory and Practice, 43, Tall Oak Pub. Co. (1995)

Effect of Chlorine (Oxidizing Chemical)

When effluent is used for polymer mixing, chlorine should be < 3 mg/L

0

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400

600

800

1000

1200

0 1 2 3 4 5 6 7 8 9 10

Vis

co

sit

y

Cl2mg/L

cP

Polymer Activation (Mixing, Dissolution)

(I) Initial Wetting (Inversion)Sticky layer formed

High-energy mixing -> No fisheyes

Most Critical Stage

(II) Dissolution

Reptation* or Uncoiling

Low-energy mixing -> No damage to polymer

Sticky Layer

WaterPolymer (gel)

* de Gennes, P.G., J. Chem. Phys., 55, 572 (1971)

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time

(I) (II)

Oil

Two-Stage Mixing (in mix chamber) higher energy mixing low energy mixing

“Discrete” Two-Stage Mixing(discrete means “separation of highand low energy mixing zones”)

One-stage vs. Two-stage Mixer – Emulsion Polymer

G-value, mean shear rate (sec-1)

1,700

4,000

1,100

1- stage mixer 2- stage mixer

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Dividing Baffle

Mixing Effect on Polymer Activation

Two-stage mixing significant increase of polymer solution efficiency

226

427

310

523

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100

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300

400

500

600

Anionic Polymer Cationic Polymer

Viscosity of 0.5% Emulsion Polymer Solution, cP

1-stage mixer 2-stage mixer

37% increase

22% increase

PolyBlend® Technology

Two-Step Dilution - primary mixing (in mix chamber) at high conc. (%) and post-dilution

“Discrete” Two-Stage Mixing(discrete means “separated”)

High Concentration at Initial Wetting, Optimum 0.5% wt. (1.0 - 1.5% vol.)

Two-Step Dilution: Why Primary Mixing at High Conc? Inverting Surfactant helps to “invert (or break)” stable emulsion state

Polymer Gel: Polymer 40%

Water 30%

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Hydrocarbon Oil: 30%

d

d = 0.1 - 2 µm

Inverting (breaker) surfactantTo enable inverting surfactant to work properly,

make polymer solution at high concentration** 1.0% - 1.25% primary mixing in mix chamber *** 0.25% - 0.5% secondary mixing (dilution)

* AWWA Standard for Polyacrylamide (ANSI-AWWA B453-06), 11, 2006** Polyacrylamide Emulsions Handbook, SNF Polydyne, 9, 2011

Stabilizing surfactant

Two-Step Dilution: How to Expedite Polymer Activation?

Primary MixingPost-Dilution

Primary mixing at “high %” Post-dilution to feed %

Polymer 1.0 gph

Polymer 1.0 gph

Water 400 gph

Water 300 gph

Water 100 gph

0.25% solution

0.25% solution1.0%

0.25%

Ideal Design

4 x higher content of inverting surfactant to expedite polymer activation

Primary Mixing

Example of Ideal Liquid Polymer SystemTwo-stage Mix Chamber + Two-step Dilution

high-shear mixing

low-shear mixingbaffle plate

Secondary dilution water

Primary dilution water

Two-stage Mix chamberTwo-stage

Mix chamber

Open-frame M-seriesCompact PB-series Open-Frame Magnum-series

Two-stage Dilution

High Energy Mixing

(3,450 rpm, < 0.5 sec)

Low Energy Mixing

(60 rpm, 20 min)

DD4 Disperser Mix and Hold Tanks

PolyBlend® Dry Polymer System

Two-Stage Mixing

Polymer Solution

Storage/Holding

(no mixing)

First-Stage of Dry Polymer Mixing:

High Energy Initial Wetting

Very High-Energy Mixing for Short Time

G = 15,000 sec-1

3,450 rpm for < 0.5 sec

Disperses Individual Polymer Particles

* No Fisheye Formation

* Shorter Mixing Time in Next Stage

Water in

Solution Out

Why Initial High-Energy Mixing is So Critical?

Polymer dissolution time, ts ~ (diameter)2 Tanaka (1979)*

d

10*d

Assume ts 1 min

ts 100 min

Initial high-energy mixing No fisheyes Significantly shorter mixing time

* Tanaka, T., Fillmore, D.J., J. Chem. Phys., 70 (3), 1214 (1979)

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Large Impeller, 70% of tank diameter

Uniform Mixing Energy

Low RPM, < 60 rpm

Low-intensity Mixing

Minimize Damage to Polymer Chain

Shorter Mixing Time with high-energy initial wetting

20 Minutes for Cationic Polymer

30 Minutes for Anionic Polymer

Minimize Damage to Polymer Chain

Second-Stage of Dry Polymer Mixing:

Low Energy Uniform Mixing

• Solano County, CA, 40 miles North San Francisco• Design capacity: 24 MGD tertiary treatment/ UV• Population served: 135,000• Polymer use for dewatering (screw press) and

thickening (GBT)

Problems with existing polymer system• Struggled to make proper polymer solution• Non-homogeneous polymer solution• Frequent maintenance issues

FKC screw press runs at average 70 gpm of sludge

(2% solids content)

Case Study: Fairfield-Suisun Sewer District, CA

Pilot Testing with Two Polymer Mix Equipment

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Existing Polymer System• Initial wetting: air blower –> wetting head• Mixing: two (2) 4,600 gal mix/age tanks• 1 hour mixing and 2 - 4 hour aging time

UGSI PolyBlend Dry Polymer Demo System• Initial wetting: high-energy mechanical mixing • Mixing: two (2) 360 gal mix tanks • 20 minute mixing, 10+ minute transfer time

Polymer Feeder/Blower Downstairs Water Jet Wetting Head

New Polymer System (PolyBlend® DP2000) Installation

Replaced:Two 4,600 Gallon Mixing/Aging Tanks

* 6 - 12 Hour Aging Time* Corrosion Issues

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With:Two 1,000 Gallon Mixing/Feed Tanks

* 0 - 25 Minute Aging (holding) Time

New System (PolyBlend® DP2000) Performance

38.3 38.4

35.2 34.5

19.6

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2500

3000

0

5

10

15

20

25

30

35

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45

2012 2013 2014 2015 2016

FSSD saved 42% on Screw Press Polymer in 2016

despite an increase in solids throughput of 18%

Slu

dge

Pro

cess

ed, D

T/ye

ar

How to Achieve this Result?initial high-energy mixing is critical

Polymer dissolution time, ts ~ (diameter)2 Tanaka (1979)*

d

10*d

Assume ts 1 min

ts 100 min

Initial high-energy mixing (DD4) No fisheye formation Significantly shorter mixing time Less damage to polymer structure Better quality polymer solution Less Polymer Used

* Tanaka, T., Fillmore, D.J., J. Chem. Phys., 70 (3), 1214 (1979)

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Three Forms of Polymer Solutions

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Broken polymer chains by excessive mixing

Neat polymer

Fisheyes due to poorinitial wetting

Ideal polymer chains by two-stage mixing

• Located 35 miles Northeast Philadelphia• Operating capacity: 16 MGD• Population served: 40,000• Emulsion polymer use for dewatering alum-carbon

sludge with two belt filter presses (K-S)

Case Study: Water Treatment Plant, PA(Liquid/Emulsion Polymer System)

Existing Polymer SystemSiemens M1200-D10AA (2011)

New Polymer SystemUGSI MM1200-D10AA (2016)

Performance Comparison of Two Mix Chambers

PolyBlend® MM-series Mix Chamber

Residence time in low energy zone (VL ) tripled

Upgrades: Quick Disconnect Polymer Injection Check Valve

(3,450 rpm brass impeller, G value 14,000 sec-1)VHVL baffle

[VL.new= 3 x VL.old] [VH.new= VH.old ]

Polymer In

Solution Out

Water In

Quick-Disconnect PinPolymer Check Valve

• Side-by-Side Trial, Feb - May, 2016

• Polymer savings: 30% - 35%

Results of Three month Trial (1/2)

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

2/9/16 2/16/16 2/23/16 3/1/16 3/8/16 3/15/16 3/22/16 3/29/16 4/5/16 4/12/16 4/19/16 4/26/16 5/3/16 5/10/16 5/17/16

Poly

mer

Usa

ge, l

b/t

on

Test Date

Polymer Usage of Two PolyBlend Systems

M2400

MM2400

15.0

17.0

19.0

21.0

23.0

25.0

27.0

29.0

5 10 15 20 25 30 35

% C

ake

Solid

s

Polymer Usage (lb/ton)

Existing M2400-D10AA M2400-D10AA with Extended Mix Chamber

Existing M2400-D10AA M2400-D10AA with Extended Mix Chamber

Drier cake solids, 22% 23% with new polymer system

Results of Three month Trial (2/2)

Emulsion Polymer Configuration

Polymer Gel: Polymer 40%

Water 30%

Hydrocarbon Oil: 30%

d

d = 0.1 to 2 µm

Stabilizing Surfactant

Inverting (Breaker) Surfactant

Storage of Emulsion Polymer

* Drum (Tote) Mixer

* Recirculation Pump

Separated Oil

Concentrated Polymer Gels

* Drum (Tank) Dryer

Moisture Intrusion Separation (stratification)

M

Summary – Polymer Activation

31

Dilution water

Hardness < 300 mg/l), Cl2 < 3 mg/l, Temperature > 60 oF

Effect of Mixing

Two-stage mixing in primary mix chamber

Two-step Dilution: Primary mixing @ > 1%, then post-dilution

(AWWA Std. B453-06)

Case 1: Fairfield-Suisun WWTP (Dry)

Case 2: PA WTP (Emulsion, new Magnum)

Thank YouAny Questions?