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CEEN 572 Environmental Engineering Pilot Plant Laboratory Introduction. Instructor: Prof. Tzahi Cath ( tcath@ mines.edu ) TA: Liz Bell ( ebell@mines.edu ). Course objectives. Apply knowledge and understanding of water treatment processes to a real-world problem
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CEEN 572Environmental Engineering Pilot Plant Laboratory Introduction Instructor: Prof. Tzahi Cath (tcath@mines.edu) TA: Liz Bell (ebell@mines.edu)
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 • 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 • 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 • Laboratory reports and presentations 25% • Participation and peer evaluation 30% • Project Presentation 15% • Final Report 30%
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 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 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 • 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 • 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 • Develop isotherms • Test different adsorbents • Test different adsorbates • Temperature effects • Time
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 • 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 • 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 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.) 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 • 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
Coagulation/Flocculation Rapid mix Flocculator
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 Satisfy Electroneutrality
Destabilization Mechanisms • Compression of the double layer (DLVO Theory) • increasing the ionic strength
Destabilization Mechanisms • Compression of the double layer (DLVO Theory) • increasing the ionic strength • Adsorption and charge neutralization • adding a coagulant (metal salt)
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 Al2(SO4) 3 +
Al2(SO4) 3 Sweep-Floc Coagulation Al2(SO4) 3 + + colloids are enmeshed
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 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 Overall stoichiometric reaction Al3+ + 3H2O <-> Al(OH)3(am) + 3H+ Fe3+ + 3H2O <-> Fe(OH)3(am) + 3H+ H+ will react with alkalinity FeCl36H2O + 3HCO3-<-> Fe(OH)3(am)+ 3Cl- + 3CO2+ 6H2O Fe(SO)49H2O + 6HCO3-<-> 2Fe(OH)3(am) + 3SO42- + 6CO2+ 9H2O Al2(SO4)314 H2O + 6HCO3- <-> 2Al(OH)3)(am)+ 3SO42-+ 6CO2+ 14H2O
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 • 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 • 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 • 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 • 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 • Sedimentation • Interception • Brownian Diffusion A Collector B C
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 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