Ceen 572 environmental engineering pilot plant laboratory introduction
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CEEN 572 Environmental Engineering Pilot Plant Laboratory Introduction. Instructor: Prof. Tzahi Cath ( tcath@ mines.edu ) TA: Liz Bell ( [email protected] ). Course objectives. Apply knowledge and understanding of water treatment processes to a real-world problem

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CEEN 572 Environmental Engineering Pilot Plant Laboratory Introduction

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Ceen 572 environmental engineering pilot plant laboratory introduction

CEEN 572Environmental Engineering Pilot Plant Laboratory Introduction

Instructor: Prof. Tzahi Cath ([email protected])

TA: Liz Bell ([email protected])


Course objectives

Course objectives

  • Apply knowledge and understanding of water treatment processes to a real-world problem

  • Enhance students ability to apply math, science, and engineering concepts and skills to the analysis, design, and optimization of drinking water treatment systems

  • Teach students to effectively communicate the results of their technical work through professional quality written reports and oral presentations

  • Enhance teamwork skills through team project assignments


Course organization

Course organization

  • Meeting time Wed 2-5 pm and Fri 1-3 pm in CO 210 and IETL (CO 166 or Golden Water Treatment Plant)

  • Course webpage:

    http://inside.mines.edu/~tcath/courses/CEEN572_pilot/

  • Office hours: CH 128 by appointment

  • Textbook: No specific textbook recommended. Course webpage is resource


References for ceen 572

References for CEEN 572

  • HDR Engineering Inc. (2001). Handbook of Public Water Systems. 2nd Edition. John Wiley & Sons, Inc.

  • American Water Works Association (1999). Water Quality and Treatment. Fifth Edition. McGraw-Hill.

  • American Water Works Association (1998). Water Treatment Plant Design. Third Edition. McGraw-Hill.

  • Faust. S. and Aly, O. (1999). Chemistry of Water Treatment. 2ndEdition. Lewis Publishers.

  • Qasim, S. R., Motley, E. M., Zhu, G. (2000). Water Works Engineering. Planning, Design & Operation. Published by Prentice Hall PTR

  • MWH (2005). Water Treatment: Principles and Design. 2nd Edition. John Wiley & Sons, Inc.

  • Howe, K. and Clark, M. (2002). Coagulation Pretreatment for Membrane Filtration. AwwaRF Report

  • AWWA (2005). Microfiltration and Ultrafiltration Membranes for Drinking Water. Manual of Water Supply Practices M 53.


Grading ceen 572

Grading CEEN 572

  • Laboratory reports and presentations25%

  • Participation and peer evaluation30%

  • Project Presentation15%

  • Final Report 30%


What do i need to know

What do I need to know?

  • Fluid Mechanics: Bulk fluid properties, mass conservation equations, laminar/turbulent flow regimes, reactor flow models

  • General knowledge in conventional water treatment (also prerequisites): CEEN 470 (ESGN 453); CEEN 471 (ESGN 453); CEEN 570 (ESGN 504); CEEN 571 (ESGN 506)

  • or consent of the instructor


Golden water treatment plant

Golden Water Treatment Plant


Conventional water treatment

Conventional Water Treatment


Golden water treatment plant1

Golden Water Treatment Plant

SPLIT TRAIN (RAPID MIX, FLOCCULATION, SEDIMENTATION)

RAW WATER FROM CLEAR CREEK

KMnO4(PRE-OXIDATION)

FLOC AID

NaOH

Cl2

FERRIC SULFATE

PRESEDIMENTATION & STORAGE PONDS

RAW WATER PUMP STATION

RAPID

MIX

SODA ASH

FLOCCULATION

SETTLER

MULTIMEDIA FILTRATION

Cl2

DISTRIBUTION SYSTEM

CLEARWELL

HIGH SERVICE

PUMPS


Golden water treatment plant2

Golden Water Treatment Plant


Golden water treatment plant3

Golden Water Treatment Plant

  • The Golden water treatment plant has just upgraded the multimedia filters:

    • New underdrain (leopold® vs. gravel/rocks) http://www.xylemwatersolutions.com/scs/usa/Documents/LB003-1326_Leopold_TypeS_Underdrain_Brochure_sm.pdf

    • Dual media vs. mixed media

      • New sand

    • Conventional filtration vs. greensand filtration

  • To satisfy Level 3 Partnership for Safe Water, the settled turbidity should be <1 NTU and filtered turbidity < 0.1 NTU


Understanding the problem

Understanding the Problem

  • In recent years, and especially during the last rain/flood event, the Golden water treatment plant has overwhelmed with high TOC (DBP precursor…) and taste & odor compounds in the source water

  • In the past, the Golden water treatment plant had the infrastructure to dose powdered activated carbon (PAC) in the flocculation basing to adsorb these compounds. This capability was lost years ago.


Research questions

Research Questions

  • How and where can we introduce PAC on demand to optimize TOC and T&O removal?

  • What PAC should we use and at what dose and intervals?

  • How can we achieve the above without compromising oxidation (KMnO4) for Mn removal and disinfection (Cl2) for pathogen removal?

  • How PAC addition will affect sludge production and characteristics and filter performance?


Batch testing

Batch Testing

  • Develop isotherms

  • Test different adsorbents

  • Test different adsorbates

  • Temperature effects

  • Time


Csm golden pilot plant

CSM-Golden Pilot Plant


Mini pilot treatment system

Mini-Pilot Treatment System


Mini pilot flow diagram

pH adjustment

Backwash

Waste

Chlorine

V-2

V-3

V-2

V-13

V-14

Coag.

V-1

KMnO4

V-11

V-4

V-5

V-12

V-10

Backwash

Lines

V-7

V-9

pH

Mini-Pilot Flow Diagram

Flocculation Basin

Overflow

Feed

Tank

turbidimeter

V-6

V-8


Team assignments

Team Assignments

  • Compile information on relevant federal and state regulations for TOC, DBPs, T&O, turbidity, manganese removal, and filtration conditions related to surface water treatment plants. Prepare presentation for January 22 (21?)

  • Compile data from Golden water treatment plant and prepare a presentation and discussion for our meeting on January 22 (21?)

  • Conduct review on conventional treatment processes for TOC and T&O form surface water, including PAC and GAC and compare the two

  • Develop draft experimental plan for pilot scale study using the IETL filtration pilot systems


Lab safety for ceen 572 general laboratory rules

Lab Safety for CEEN 572:General Laboratory Rules

  • Use safety glasses at all times in the laboratory

    • You must use safety glasses during transport of chemicals between labs

  • Use laboratory coats when working in the laboratory

    • Don’t use them outside of a laboratory (except when moving between labs)

  • Use gloves when handling chemicals (see label and MSDS)

    • Remove gloves when leaving the laboratory

  • Biological and chemical materials must be transported between laboratories:

    • with secondary containment (e.g., bucket or cart with raised sides)

    • with lab coat and gloves

    • with safety glasses worn


Lab safety for ceen 572 general laboratory rules1

Lab Safety for CEEN 572:General Laboratory Rules

  • Closed-toed shoes must be worn at all times

  • Hands must be washed with soap before leaving the laboratory

  • No food, beverages, or cosmetics are allowed at any place within the laboratory

  • Hair that is long enough to reach the shoulders must be tied back

  • All containers of samples or chemicals must be labeled

  • All benches and hoods must be kept free of clutter, dust, and residue from any spills

  • All benches must be wiped clean after use

  • All sinks must be kept free of glassware and instrumentation

  • All instrumentation, particularly balances, must be thoroughly cleaned after use


Lab safety for ceen 572 cont

Lab Safety for CEEN 572 (cont.)

Waste Disposal

  • All chemical waste must be disposed of in designated waste containers

  • All containers must be labeled with contents and date

  • Contact wastes: collect in designated yellow buckets

    Individual Responsibilities

  • Notify the supervising faculty of any medical conditions that could be affected by carrying out laboratory activities

  • Notify the supervising faculty of any safety concerns

  • Observe the above laboratory rules

  • Assist other laboratory users in observing general rules

  • Immediately clean routine spills

  • Immediately report non-routine spills to the supervising faculty and to EHS

  • Memorize locations and uses of all exits, eye-wash stations, showers, fire alarms, and emergency phones


Lab safety for ceen 572 golden water treatment plant

Lab Safety for CEEN 572:Golden Water Treatment Plant

  • Over the years we have established VERY GOOD relationships with the city of Golden (!!!)

  • You will receive access to the water treatment plant.

    • THIS IS NOT OBVIOUS AND REQUIRE CAREFUL AND OUTMOST PROPER BEHAVIOR

  • Announce visiting plans

  • Report in and out

  • Don’t take things without permission

  • Return things to their place

  • Use of lab

  • Hygiene


Semester schedule

Semester Schedule


Overview of conventional water treatment

Overview of Conventional Water Treatment


Coagulation flocculation

Coagulation/Flocculation

Rapid mix

Flocculator


Turbidity in water colloid surface phenomena

Turbidity in Water:Colloid Surface Phenomena

  • Electrostatic force

    • principal force contributing to stability of suspension

    • electrically charged particles

  • Van der Waals force

    • attraction between any two masses

    • opposing force to electrostatic forces


Double layer model of colloidal particles

Double Layer Model of Colloidal Particles

Satisfy Electroneutrality


Forces acting on colloids

Forces Acting on Colloids


Destabilization mechanisms

Destabilization Mechanisms

  • Compression of the double layer (DLVO Theory)

    • increasing the ionic strength


Compression of double layer

Compression of Double Layer


Destabilization mechanisms1

Destabilization Mechanisms

  • Compression of the double layer (DLVO Theory)

    • increasing the ionic strength

  • Adsorption and charge neutralization

    • adding a coagulant (metal salt)


Charge neutralization

Charge Neutralization


Destabilization mechanisms2

Destabilization mechanisms

  • Compression of the double layer (DLVO Theory)

    • increasing the ionic strength

  • Adsorption and charge neutralization

    • adding a coagulant (metal salt)

  • Enmeshment in a precipitate (“sweep-floc coagulation”)

    • high coagulant dose (metal salt)

    • coagulant forms insoluble precipitates

    • dominant mechanism applied (pH 6-8)


Sweep floc coagulation

Sweep-Floc Coagulation

Al2(SO4) 3

+


Sweep floc coagulation1

Al2(SO4) 3

Sweep-Floc Coagulation

Al2(SO4) 3

+

+

colloids are enmeshed


Restabilization

Restabilization


Destabilization mechanisms3

Destabilization Mechanisms

  • Compression of the double layer (DLVO Theory)

    • increasing the ionic strength

  • Adsorption and charge neutralization

    • adding a coagulant (metal salt)

  • Enmeshment in a precipitate (“sweep-floc coagulation”)

    • high coagulant dose (metal salt)

    • coagulant forms insoluble precipitates

    • dominant mechanism applied (pH 6-8)

  • Interparticle bridging

    • synthetic organic polymer


Destabilization of colloidal particles

Destabilization of colloidal particles

Metals salts used for destabilization:

  • aluminum sulfate (alum)

  • aluminum chloride

  • ferric sulfate

  • ferric chloride

  • ferrous sulfate

Solubility of metals salts:

Operating range


Stoichiometry of metal ion coagulants

Stoichiometry of Metal Ion Coagulants

Overall stoichiometric reaction

Al3+ + 3H2O <-> Al(OH)3(am) + 3H+

Fe3+ + 3H2O <-> Fe(OH)3(am) + 3H+

H+ will react with alkalinity

FeCl36H2O + 3HCO3-<-> Fe(OH)3(am)+ 3Cl- + 3CO2+ 6H2O

Fe(SO)49H2O + 6HCO3-<-> 2Fe(OH)3(am) + 3SO42- + 6CO2+ 9H2O

Al2(SO4)314 H2O + 6HCO3- <-> 2Al(OH)3)(am)+ 3SO42-+ 6CO2+ 14H2O


Coagulation using different coagulants

Coagulation Using Different Coagulants


Design of coagulation processes

Design of coagulation processes

  • The design of coagulation process involves:

    • Selection of proper coagulant chemicals and their dosing

    • Design of rapid mixing and flocculation basins

  • Coagulation (chemical conditioning)

  • Flocculation (physical conditioning)


Sedimentation

Sedimentation


Sedimentation1

Sedimentation

  • Removal of largest particles for increased filtration run times

  • Achieves about 1-log removal (90%) of particles

  • Extra buffering for raw water upset

  • Required in treatment of many surface waters


Mechanism and types of sedimentation

Mechanism and Types of Sedimentation

  • Physical treatment process that utilizes gravity to separate solids from liquids

  • Types of sedimentation

    • Type I: discrete settling (i.e., settling of silt; pre-sedimentation)

    • Type II: flocculant settling (i.e., coagulated surface water)

    • Type III: hindered settling/zone settling (i.e., upper portion of sludge blanket in sludge thickener)

    • Type IV: compression settling (i.e., lower portion of a gravity sludge thickener)


Media filtration

Media Filtration

  • Gravity filters:

  • 2-3 m head

  • housed in open concrete or steel tanks

  • large and small systems

  • Pressure filters:

  • higher head

  • housed in closed steel vessels

  • costly; small systems


Granular media filtration theory

Granular Media Filtration Theory

  • Particles being captured can be 100-1,000 times smaller than the pores

    • Obviously not straining

  • Mechanisms of Filtration

    • Transport to the Media Surface

    • Attachment


Transport mechanisms during granular media filtration

Transport Mechanisms During Granular Media Filtration

  • Sedimentation

  • Interception

  • Brownian Diffusion

A

Collector

B

C


Disinfection chlorine clo 2

Disinfection – Chlorine/ClO2


Regulations and water quality standards

Regulations and Water Quality Standards

  • Federal Requirements

  • State regulations

  • Golden WTP: Level III Partnership for Safe Water Quality

    • The Partnership for Safe Water is a voluntary effort that encourages public water systems to survey their facilities, treatment processes, operating and maintenance procedures, and management oversight practices. It is geared toward filter plants that obtain source water from reservoirs, lakes, rivers and streams. The Partnership’s goal is to provide a new measure of safety. The program’s self-assessments identify areas that will enhance the water system’s ability to prevent entry of Cryptosporidium, Giardia and other microbial contaminants into the treated water. At the same time, system staff can voluntarily make corrections that are appropriate for the water system. In essence, the preventative measures are based on optimizing treatment plant performance and thus increasing protection against microbial contamination in the state’s drinking water supplies.


Regulations and water quality standards1

Regulations and Water Quality Standards

  • Federal Requirements

    • 0.3 NTU (95%) not to exceed 1

    • Fe: secondary maximum contaminant level: 0.3 mg/L

    • Mn: secondary maximum contaminant level: 0.050 mg/L

      • Complaints received when Mn is > 0.015 mg/L

  • Golden WTP: Level III Partnership for Safe Water Quality

    • 0.1 NTU (95%) (15 minute intervals)

    • Strict SOP’s for Operations

    • Stringent Reporting Guidelines

    • 2nd plant in State, 7th in the Nation


Clear creek watershed

Clear Creek Watershed


Mn in raw surface water in u s source waterstats

Mn in Raw Surface Water in U.S.(Source: WaterStats)

Golden’s Current

Avg. Mn = 0.15 - 0.20


Manganese chemistry

Manganese Chemistry

  • Potassium permanganate (KMnO4)

    • Oxidant, bactericide, algaecide, deodorizers, used to purify drinking water, treat wastewater

  • MnCl2

    • chemical intermediate, catalyst, feed supplement, batteries

  • MnSO4

    • fertilizer, varnishes, glazes, fungicide, nutritional supplement

  • MnO2

    • batteries, matches, fireworks, amethyst glass, chemical intermediate


Manganese chemistry1

Manganese Chemistry

  • Divalent manganese is a reducing agent

    • Can lose electrons - become oxidized

  • Tetravalent manganese is a good oxidising agent

  • Heptavalent manganese is a powerful oxidising agent

    • Can gain electrons - become reduced


Manganese chemistry reactions of manganese compounds

Manganese ChemistryReactions of Manganese Compounds

  • Metal

    • Oxidizes superficially in air, rusts in moist air

    • Dissolves readily in dilute mineral acids

      Mn(s) + 2H+ Mn2+ + H2

  • Oxides

    • Most stable MnO2 – Manganese dioxide

    • Lower oxides basic – MnIIO, MnIII2O3

    • Higher oxides acidic – MnIVO2, MnVII2O2


Manganese chemistry reactions of manganese compounds1

Manganese ChemistryReactions of Manganese Compounds


Manganese chemistry reactions of manganese compounds2

Although the mechanism of Mn reaction is not understood completely, the following general expression may be used to describe the oxidation in a Completely Mixed Batch Reactor:

K1, k2 = rate constants of oxidative and autocatalytic pathways, respectively

[Mn2+] = aqueous-phase manganese ion concentration, mol/L

[MnO2(s)] = manganese oxide precipitate concentration, mol/L

Manganese ChemistryReactions of Manganese Compounds


Manganese chemistry reactions of manganese compounds3

An alternative rate expression has been presented for the oxidation of Mn2+ to MnO2 using potassium permanganate:

K1 = rate constants of oxidative pathway, 9.55x1012 s-1(mol/L)-2.1

[Mn2+] = aqueous-phase manganese ion concentration, mol/L

[KMnO4] = aqueous-phase KMnO4 concentration, mol/L

[OH-] = aqueous-phase hydroxide ion concentration, mol/L

k2 = rate constants of autocatalytic pathway, 8.7x103 s-1(mol/L)-1

[Mn2+]e = aqueous-phase Mn2+ ion concentration in finished water, mol/L

[MnO2(s)] = manganese oxide precipitate concentration, mol/L

Manganese ChemistryReactions of Manganese Compounds


Measures to improve manganese removal

Natural negative surface charge

-

-

Mn2+

-

Filter

Media

-

HOCl

Mn2+

-

HOCl

Mn2+

-

HOCl

Mn2+

Mn2+

Mn2+

Mn2+

HOCl

HOCl

Mn2+

HOCl

HOCl

Mn2+

Mn2+ + HOCl + H2O <-> MnO2(s) + Cl- +3H+

Measures to Improve Manganese Removal

  • Lower Mn levels can be achieved by adsorption/oxidation process (“Greensand” filtration) than through particle removal


Measures to improve manganese removal1

Measures to Improve Manganese Removal

  • Mn levels in Clear Creek too high during Spring run-off for adsorption/oxidation to be fully effective (need to be < 0.5 mg/L)

  • Multiple Barrier Approach

    • Pre-oxidation to create Mn precipitates

    • Coagulation, Floc/Sed and filtration to remove Mn precipitates

    • Pre-chlorination across filters to polish Mn removals via adsorption/oxidation process


Oxidation followed by adsorption filtration

Step 1: Add enough oxidant to oxidize a portion of the

Mn – allow some to stay in soluble form

FILTRATION

DISTRIBUTION SYSTEM

CONVENTIONAL TREATMENT: MIXING, FLOCCULATION, & SEDIMENTATION

SOURCE WATER RESERVOIR

FINISHED WATER RESERVOIR

Maintain free chlorine residual

Step 3: Soluble Mn removed via adsorption onto filter media.

Add chlorine onto filters, this “regenerates” media and allows for

continued adsorption

Oxidation followed by Adsorption & Filtration

Step 2: Particles removed

via standard conventional

treatment


Viable oxidants

Viable Oxidants

  • KMnO4 (1.44 mg per mg Mn)

  • ClO2(g) (0.49 mg per mg Mn)

  • Cl2(g), or HOCl (1.29 mg Cl2 per mg Mn)


Kmno 4 as oxidant of choice

KMnO4 as Oxidant of Choice

  • Fast reaction times at high pH (>8)

  • Overfeeding can cause colored water and higher Mn concentration

  • Liquid Concentrate

    • Continuous feeding pump that canbe flow paced

  • Solid Chemical Mixer


Kmno 4 and cl 2 dosing strategies

KMnO4 and Cl2 Dosing Strategies

  • Deliberately “Under Dose” KMnO4 to prevent pink water and leave final polishing to adsorption/ oxidation process

  • Set KMnO4 to 80-90% of stoichiometric dose

  • Target 0.10 mg/L KMnO4 to ensure no pink color in finished water

  • Feed enough Cl2 ahead of filters to assure >1.0 mg/L residual in finished water and maintain high Mn/Fe adsorption affinity of MnO2 coating


Kmno 4 and cl 2 dose requirements

KMnO4 and Cl2 Dose Requirements

  • 0.94 mg KMnO4 per mg of Fe+2

  • 1.92 mg of KMnO4 per mg of Mn+2

  • 0.62 mg Cl2 per mg of Fe+2

  • 1.27 mg Cl2 per mg of Mn+2

  • KMnO4 reacts fast (seconds/minutes)

  • Cl2 reacts more slowly (hours)


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