8 -Contact Water Filtration - Severn Trent - Steel...

Contact Water FiltrationContact Water FiltrationPresented to:

Steel Making Water ConferenceCLEARWATER, FLORIDA

Prepared by:

Mr. Charles J. GuzelliIndustrial Sales Manager

13 September 2012

ChemTreat’s Steel Industry Water Conference 9-12 to 9-14-2012 , Clearwater Beach FL* Confidential * Do Not Duplicate without Permission

1

CHARLES J. GUZELLIIndustrial Sales ManagerIndustrial Sales Manager

Career - With Dravo / Tetra / Severn Trent - 30 years Dravo Corporation Machine Shop Production Manager Dravo Corporation - Machine Shop Production Manager Blaw Knox Mill Machinery - Class A EstimatorWean United Engineering - Chief Estimator Dravo Corporation - Proposal Engineer Tetra Technologies - STS

1988 to 1993 - Chief Estimator 1993 to 1994 - Field Service Manager 1994 to 1997 - Senior Project Manager 1995 - Construction Managerg 1997 to 1999 - Proposal Manager 1999 to - Industrial Sales Manager


Education - RMC / Business: PITT / Mechanical Eng’r2

METHODS OF TREATMENTVarious treatment processes in US Steel market

- Once pass through systems with no treatmentOnce pass through systems with no treatment- Sedimentation Basins and Dragout Conveyors- Mixed bed and multi-media Filtration Systems

Horizontal Clarifiers and Settling Basins- Horizontal Clarifiers and Settling Basins- Ponds and Lagoons- 1959 DRAVO introduces Mono-media Filter to USA- 1962 DRAVO begins to install Filters in Refineries- 1965 DRAVO begins to install Filters in Steel Mills

1968 Cl AIR t d b US G t- 1968 Clean AIR act passed by US Government- 1972 Clean WATER act passed by US Government

Continuous Backwash Filters and EMF Filters


- Continuous Backwash Filters and EMF Filters- Future ?????

3

FILTRATION BENEFITSFILTRATION BENEFITSFilters help Steel Producers achieve:

Higher Steel Production through more usable water- Improving Mill Efficiency through even cooling

Impro ing Prod ct Q alit- Improving Product Quality- Reducing Maintenance

MORE WATER = MORE STEELMORE WATER = MORE STEEL- No strainer - spray nozzle plugging at Casting Machine- Fewer Roll turn downs at the Rolling MillFewer Roll turn downs at the Rolling Mill- Fewer Roll change outs at Mill Stands

These are all indirect benefits of


having clean water return to the process4

FILTRATION BENEFITSFILTRATION BENEFITS

Selection of Filters should achieve following:Selection of Filters should achieve following:- Full time operators should not be required- Low or no maintenance requiredq- Robust “bulletproof” reliability- Low energy consumption use

Low / no chemical usage- Low / no chemical usage- Low Backwash water- Filter Longevity

YOU MAKE STEEL - FILTERS MAKE WATERThese are the direct benefits of


selecting a Filter System for an application5

Steel Mill Recycle / Reuse Contact WaterDIRECT FROM SCALE PIT - No settlingDIRECT FROM SCALE PIT No settling

Hot Rolling Mill D l S l

Mill Scale, Solids and

O&G removal

G it Filt

Rolling Mill Contact WaterHot Rolling Millfor shaping final

Products

DescaleLaminar

Reheat furnaceScale

PitGravity Filteror Pressure

Filter SystemDirty

Backwash toVOD - Degas

Filtered Water Returns to Mill Cooling Tower

Mill Scale Solids and

De-watering

Casting MachineMakes scrap

90 tonl dl

Gravity Filteror Press reScale

Mill Scale, Solids andO&G removal

LMF

Caster Spray Water Return

Makes scrap into steel forms

ladle or PressureFilter System

ScalePit

Filtered Water Returns to CasterCooling Tower

DirtyBackwash to


Cooling Tower De-watering

NO WATER from Filter System is discharged to the Environment 6

DISCUSSION OVERVIEWMill Water Contact SystemsMill Water Contact Systems

FILTRATION Design Basics Applications Applications

INTERNALS Underdrain System Media

BACKWASHINGMAINTENANCE


MAINTENANCE7

DESIGN BASICS

• Flow Rate - Average and Max1. Determines # of Filters Required

- Hydraulics is sized on gpm / sq ftBased on Size of Particles- Based on Size of Particles

2. Pounds of Solids (type and size) Removed- Calculated on loadings - surface areag

• Water Characteristics1 TSS (Total Suspended Solids) - Average & Max1. TSS (Total Suspended Solids) Average & Max

- Mill Scale - Particle Size Distribution2. O&G (Oil and Grease) - Average & Max


- Open or closed lube system - synthetic?8

DESIGN BASICS• What is upstream of Filter System?1. Scale Pit

D i d T f Pit Pit R t ti Ti- Design and Type of Pit; Pit Retention Time- Pit Maintenance; frequency and how is it cleaned

2. Oil and Grease Removal Systems2. Oil and Grease Removal Systems- Skimmers, Ropes, Mops, Beaches

• Where does effluent & dirty backwash go?& y g1. Effluent

- Returns to Mill for Reuse - discharged to surface2. Dirty Backwash Water

- Return to Scale Pit- De-watering Circuit


- De-watering Circuit- mudwell - thickener - filter press

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APPLICATIONS• Casting Machines1 Water that is pumped from scale pit through a1. Water that is pumped from scale pit through a

filter system and returned to spray nozzles • Contact Water1. Water used to cool in steel in Rolling Process

Can be on HM - Laminar, Descale, DegasRi d W ll W M k S• River and Well Water Make up Systems

• Cooling Tower Side-stream Systems• Non Contact - Not Suitable for Sand Filters1. Machine Water and Mold Water2 Process Water


2. Process Water

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FILTRATION BASICSFILTRATION BASICS

TWO (2) OPERATING PHASES( )1. Filtration

- Removing Particles from a Water Source2. Backwashing

- Removing Captured Particles from Filter Media

TWO (2) TYPES f FILTER OPERATIONTWO (2) TYPES of FILTER OPERATION1. Continuous

Traveling Bridge Continuous Backwash Filters-Traveling Bridge, Continuous Backwash Filters2. Semi-Continuous

- Most Gravity and Pressure Filter Systems


y y

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FILTRATION

….. is a Physical Process….. is a Physical Process

Captured Solids

Wastewater withWastewater withSuspended Solids and Oils / Grease

Clear Filtrate


Filter Medium ( IN THIS CASE SAND) - but can be any medium that captures solids to release

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FILTRATION SPECTRUM


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DESIGN BASICSIndustrial Filters

Filter Bed Solids Loadingg Pressure Filters Range Between 4 and 8 lbs./ft2 Gravity Filters Range Between 1 and 4 lbs./ft2 Filter Bed Solids Loading Varies Based on: Filter Bed Solids Loading Varies Based on:

Type of Solid Being Filtered Size of Solid Being Filtered Available Head Available Head

When Does Backwash Occur When Maximum Headloss is ReachedWhen Maximum Headloss is Reached

Pressure System Designed for 15 psi P Effluent Quality Deteriorates

B k h F C l l t d B d L di


Backwash Frequency Calculated Based on Loading Need to Know TSS & Flow 14

DESIGN BASICSDESIGN BASICSHOW THE PROCESS WORKS

Forward Flow• Down-flow or Up-flow Filtration

Filt ti R t i /ft2• Filtration Rate in gpm/ft2

Flow Control (Constant Rate vs. Variable Declining Rate)Constant RateConstant Rate

• Weir Levels (Gravity Filters)• Influent / Effluent Flow Control (Gravity or Pressure)

Variable Declining RateVariable Declining RateHeadloss in Each Filter Determines Flow• Better Effluent Quality

L W ki H d d O ti P R i d


• Less Working Head and Operating Power Required• Longer Filter Runs

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CONSTANT verses VDRCONSTANT verses VDR

Constant Requires Individual Flow on each filter Requires Individual dP on each filter Requires Individual dP on each filter• Additional Instruments to calibrate• Additional Instrument Wiring Additional I/O required Additional I/O required

Variable Declining RateS dP i fl d ffl h d System dP across influent and effluent header

No individual Flow measurement required Less instruments = less maintenance


• Longer run time between Backwash

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Media Depth Definitions andFilt ti P tFiltration Parameters

HOW THE PROCESS WORKS Media Depth and Solids Capture

Shallow Bed Filtration Media Depth: 24 - 36 inches Media Depth: 24 - 36 inches

DeepBed Filtration Media Depth: 48 - 72 inches

Media Size and Solids Capture Too Large Media

Fi P ti l P Th h B d Finer Particles Pass Through Bed Too Small Media Driving force must overcome media too much -

Hi h H d l R l l


High Head-loss can occur Regularly*Capture Rate is defined by Hydraulics and size of particle 17

BACKWASHING METHODS Backwash

MethodBackwashWater Rate

BackwashAir Rate

(gpm/ft2) (cfm/ft2) CommentsHigh BW RatesWater Only

12 - 25 High Rates for Fluidization25 - 50% Bed ExpansionWater Only 25 - 50% Bed Expansion

Commonly Used with Fine Media and Mixed Beds

High BW Rates 12 - 25 2 – 5 High Rates for FluidizationAir Scour OnlyWater Only

25 - 50% Bed ExpansionCommonly Used with Fine Media

and Mixed BedsL BW R t 4 6 3 6 N Fl idi ti Low BW RatesAir/Water Scour is concurrently run

4 - 6 3 - 6 No Fluidization < 5% Bed Expansion

Can only be used with Coarse Mono-Media Beds


Uses Less Backwash Water Than Other Designs 18

PUMPED verses STANDPIPEPUMPED verses STANDPIPE

Pumped Backwashp Requires Additional Set of Pumps Backwash Water Flow Control Loop• Additional Manual and Check Valves• Additional Manual and Check Valves• Additional Power and Instrument Wiring May Require Holding Tank for Backwash Water

Stand-Pipe Backwash Backwash Water Taken Directly from Effluent Pipe No Pumps Required - Uses Height of Stand-Pipe for

Backpressure Valve Design Allows Correct Amount of Backwash


gWater into Filter

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BACHWASHING FLOW SHEETDirty BW Water

Influent DeepBed Cooling

FiltrationCircuit w

BW Pumps

Effluent

DeepBedGravity or Pressure

FilterClean

BackwashTank

P1

Wastewater

Tower

Filtered WaterScalePit

From Mill P2

Clean BW Water

To Mill

P3

Dirty BW Water

InfluentP1

CoolingTower

FiltrationCircuit with Standpipe

DeepBedPressure

Effluent

1 Standpipe

ScalePit

To Mill

PressureFilterWastewater

From Mill Filtered Water


Clean BW WaterNOTE:Each Mill might have a preference on Pumped verses standpipe backwash design. Many circuits draw clean water by placing a BW pump in the Cooling Tower cold-well. 20

Underdrain System

N l /S i

Nozzle-Bottom Filter

Nozzles/Strainers

FLOORFLOOR

NOZZLES

FALSE-BOTTOM


21

Underdrain System

Typical Nozzles/Strainers

yNozzle-Bottom Filter

Typical Nozzles/StrainersUsed in False-Bottom Underdrains


22

Underdrain System

N l T Fil

yNozzle-Bottom Filter

Nozzle Type Filter

DeadSpaceSpace


23

Underdrain SystemN l B tt FiltNozzle-Bottom Filter

Nozzles

Coal

SandNozzles

GravelAir scour pipe


Air Distribution HolesConcrete Piers 24

TETRA Underdrain ConstructionU de d a Co st uct o“Effluent Sump”


25

TETRA Underdrain Construction“Sump Cover Plates”


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Underdrain SystemyBackwash Air System

BW Air Injection Location Under Main Floor Directly Above Main Floor In Between Gravel and Media

Distribution Process Inject Air and Water to Same Area and Use

Floor Orifices to Distribute BothFloor Orifices to Distribute Both Backwash Air has its own Separate Piping

System for Distribution Across the Filter Area f C


Before Combining with Backwash Water

27

TETRA Underdrain Construction“Air Laterals”


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BW WATER ANDAIR DISTRIBUTION

SYSTEM• 304 SS Box HeaderW ll Thi k i 3/16”

SYSTEM

Wall Thickness is 3/16”

• Air Laterals - Schedule 40 304 SS and Other AlloysSS and Other Alloys

• Air Laterals Protected from Gravel and MediaGravel and Media Located Under T Block™ Arch


29

Underdrain SystemUnderdrain SystemUnderdrain Distribution Block

None Clay Tile BlockClay Tile Block

Plastic Nozzles

Wedge-wire Screens

Metal Fabricated Underdrain Metal Fabricated Underdrain

Snap-T; T-Block and “M” Block


30

TETRA Underdrain Construction“Concrete M Blocks”


31

TETRA Underdrain ConstructionU de d a Co st uct o“Concrete M Blocks”


32

TETRA Underdrain Construction“Plastic T and Snap-T Blocks”

Purpose1. Support structure for gravel & media2 P t l f t ti d d i2. Prevents gravel from penetrating underdrain3. Minimizes damage to filter internals from hydraulic shock4. Allows filtered water to pass through to the effluent5. Starts backwash air & water distribution across filter area


33

TETRA DeepBed® Filter Operation


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GRAVEL - Tetra ConfigurationGRAVEL - Tetra Configuration

Depth SizeLayer (inches) (inches)

No. 1 4 1-1/2 x 3/4No. 2 2 3/4 x 1/2No. 2 2 3/4 x 1/2No. 3 4 1/2 x 1/4No. 4 4 1/4 x 1/8No. 5 4 1/2 x 1/4

Rule of Thumb: Each Upper Layer is ~50% of the Size Below it


Rule of Thumb: Each Upper Layer is ~50% of the Size Below it.

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Filt M di C fi tiFilter Media Configurations

Configuration Media Type Media Size(mm)

Normal Depth(inches)

Dual Media Anthracite (Top)Sand (Bottom)

1 - 1.50.5 - 1

12 - 2412 - 24

Multi-Media Anthracite (Top) 1 - 1.5 12 - 24SandGarnet (Bottom)

0.5 - 10.4 - 0.6

12 - 243 - 6

Mono-Media Sand or Anthracite 0 5 - 2 0 36 - 72Mono Media Sand or AnthraciteSand TETRA #7 or #8Sand TETRA #5

0.5 2.0 36 7248 - 7248 - 72


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TETRA TAMPA TESTING LAB AND WAREHOUSE


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MEDIA CHARACTERISTICSSHAPE

Sphericity of > 0.8 (Perfect Sphere is 1.0) Advantage:

R d d i t d t t t d i BW• Rounded grains tend to rotate during BW• Uniform void spaces - Tetra Media has a 40% void space

which leads to greater capture and bed penetrationwhich leads to greater capture and bed penetration Non-Round Media

• Sharp angular grains interlock and increasep g gheadloss for filtration and BW.

• Angular grains stick together on large flat


surfaces preventing total bed cleaning38

MEDIA CHARACTERISTICSHARDNESS

MOH S l (1 i t l d 10 i di d) MOH Scale (1 is talc and 10 is diamond)Sand (Quartz = 7 or Silica = 8)A th it 3 5Anthracite 3.5

• Hard media minimizes attrition (wearing of media) during backwashingbackwashing

• Attrition leads to reduced media size (smaller Effective Size), therefore, higher head losses and shorter filter runs, g

• Tetra Municipal filters longevity is 20 to 35 years before filter needs rebuilt and media needs replacedTetra Industrial filters have operated 5 to 30 years before


• Tetra Industrial filters have operated 5 to 30 years before filter needs rebuilt and media needs replaced 39

TETRA DeepBed™ Filter“Silica Media”

MEDIA SPECIFICATIONMEDIA SPECIFICATION Effective Size 1.7 to 3.0 High Uniformity

Coefficient <1.40 High Sphericity >0.80 6 to 7 on MOH Scale Acid Solubility < 5%

Is coarse mono-media that allows greater solids capture and deeper bed penetrationLeading to longer run times

Carefully screened, washedand dried to the mill specific


and dried to the mill specificapplication and product mix

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BACKWASHINGBACKWASHINGTypical Mono-Media BW Sequence

• Take filter off linea e te o e• Scour Media with air-

only 2 minutes

y• Scrub media with air

and water 15 - 20 minutes

• Rinse• Put filter back on line

5 minutes

41

BACKWASH MODE

DeepBed™ Gravity FiltersAir/Water Scour


42

BACKWASHINGDirty Backwash Water

What To Do With Dirty Backwash Water

Transferred Directly to Upstream Scale Pit Must Have Ample Retention in Pit to Allow for

Increased Flow to Not Stir Up Settled Solids Must Keep Pit Cleaned of Solids to Allow Room forMust Keep Pit Cleaned of Solids to Allow Room for

Solids Settling

Transferred to Collection Tank for Transfer toSolids Handling System Mudwell, Thickener, Dewatering Equipment


43

SAND FILTRATIONSAND FILTRATION

CHEMICAL ADDITION

Influent Filter Aid May be Required to Remove Colloidal Particles Add Chemical Coagulants to Produce Pinflocs

Inorganic Coagulants are Not Recommended Inorganic Coagulants are Not Recommended Must be Careful Not to Overdose

Dirty Backwash Water for Improving Solids Settling Dirty Backwash Water for Improving Solids Settling May be Especially Important if Dirty BW Flows to

Scale Pit Upstream of Filter System


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FILTER OPERATION - Data Collection

HOW WELL IS THE SYSTEM OPERATING?

It Is Important to Monitor the Water Quality of the System

Collect Influent and Effluent Samples PeriodicallyMeasure TSS and O&G

TSS versus TurbidityC ll t l d b th TSS d T biditCollect samples and measure both TSS and Turbidity. Once a correlation is found, the turbidity can be used to monitor the operation.

Periodically, collect Dirty BW Water Samples at Beginning and End of BW and measure TSS to check the efficiency of BW


the efficiency of BW.

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FILTER OPERATIONSWHY DOES THE EFFLUENT QUALITY DETERORATE?1 Overloading Filters1. Overloading Filters

Check Influent TSS and Flow - Have They Increased? Is Scale Pit Being Cleaned on a Timely Basis? Check Backwash Frequency Check Backwash Frequency

2. Solids Are Colloidal (1-5 micron) in Nature Check All Waters Entering the System Have There Been Any Changes? Make-up Water?

Has Product Mix Changed? Are Colloids Due to Oils?

3. System Failures Hydraulic Fluid Release from Mill Occurred Backwash System or Valve Failure


Backwash System or Valve Failure Media Fouled

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FILTER OPERATIONCMaintenance Check

1. Check Media for Loss by Measuring from Top of Media to a Common Reference Point

2. Check Media for Abnormal Appearance

3. Check for Proper BW Air pattern

4 Check for Proper BW Water Rise Rate4. Check for Proper BW Water Rise RateNormal Design - 9.6 inches/minute


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FILTER OPERATIONEquipment Maintenance

Control valves• Check for Smooth Operation• Keep Limits Adjusted Properly Keep Limits Adjusted Properly• Ensure Clean Air Supply

Backwash Air Blowers Backwash Air Blowers• Check Grease & Oil Monthly• Change Oil Every 6 Months **• Grease Motor Bearings Once Per Year• Grease Motor Bearings Once Per Year• Change Air Filter Every 6 Months **• Check Belt Tension & Sheave Alignment

Every 6 Months


Every 6 Months

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Contact Water Filtration

Q ti ?Questions?


49

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