Environmental Engineering Field Session Water Treatment Module May 22 – May 29, 2015

Module Objectives  Understand the basics of surface water and wastewater treatment employing: Coagulation/flocculation/media filtration Microfiltration (MF)/Ultrafiltration (UF) Nanofiltration (NF) Oxidation  Provide insight into removal strategies for a set of contaminants during conventional and advanced water treatment  Enhance your ability to apply math, science, and engineering concepts and skills to the analysis and design of drinking water treatment systems  Learn to effectively communicate the results of your technical work through a professional quality written report

Water Treatment Module Organization  Meeting days: Fri. (5/22), Tue.-Fri. (5/26-5/29)  Meeting time: 8 am through 5 pm (+)  Meeting locations: CO 131 or as instructed (labs)  Instructors: Tzahi Cath  TAs: Tori Billings, Stephanie Riley, Liz Bell, Dotti Ramey, Jason Coontz, Estefani Bustos  Deliverables: Final written engineering report (in groups) Stephanie Riley PhD Student Tori Billings MS Student Elizabeth Bell MS Student Dotti Ramey PhD Candidate Jason Coontz MS Student Estefani Bustos Res. Associate

Schedule for the Water Treatment Module DayMorningAfternoon Friday (May 22) Introduction to water treatment (conventional & advanced) Mass balance Introduction to treatment processes and Mini-Pilot Jar-testing Water quality analysis (Mn, TOC, and turbidity) Intro to report writing MondayMemorial Day – No Class Tuesday (May 26) Experiments Lab report preparation Experiments Lab report preparation Wednesday (May 27) Experiments Lab report preparation Experiments Lab report preparation Thursday (May 28) Experiments Lab report preparation Experiments Lab report preparation Friday (May 29) Summary and evaluations Report prep

Module Grading  Laboratory summaries 20%  Participation10%  Presentation of laboratory results 20%  Engineering report 50%

Sources of water that require treatment?

What are the challenges associated with water treatment?

Typical concentrations of common water constituents in different water sources

Typical Characteristics of Untreated Municipal WW in the US

Industrial Wastewater

Treatment Dictated by Characteristics of Water Contaminants or Treatment Objectives (regulations developed to protect human health) Particles:  Coagulation/Flocculation  Sedimentation  Filtration  Flotation  Membranes Dissolved constituents  Oxidation/reduction  Precipitation  Ion Exchange  Membranes  Biological Treatment  Softening  Adsorption  Aeration Gases:  Aeration  Stripping

Conventional Water Treatment Plant

Conventional Wastewater Treatment Plant

Advanced Water/Wastewater Treatment Plant  Are there any differences between advanced water and advanced wastewater treatment?  What are the treatment objectives?  What processes?  What are the implications of using advanced treatment processes?

Target Constituents for this Field Session  Turbidity  Manganese  Hardness  Organic matter (DOC and COD)  Total dissolved solids (TDS)

Basic Process Engineering

Reactor Design Selecting Chemical Conversion Systems:  Type of reactor  Rate of reaction  Size of reactor Basis for Selection:  Stoichiometric and kinetic descriptions of chemical reactions  Flow patterns

Reactor Design Types of Chemical Reactors:  Batch reactors  Flow reactors

Reactor Design Types of Chemical Reactors:  Batch reactors: no flow and non-steady-state operation  Flow reactors: operate on continuous flow basis

Batch Reactor

 The materials balance for component i becomes  As the volume stays constant for most reactions, the expression simplifies to  For a first-order disappearance of reactant A, r = -kC A, this equation becomes C A1 V Which integrates to Batch Reactor

ProcessReactor TypePurpose OxidationStirred tanks Tanks in series Bubble tanks Venturi Oxidation of iron Oxidation of manganese Dechlorination with SO 2 Ozone reactions DisinfectionStirred tanks Tanks in series Venturi Ozone Chlorine Chloramination Coagulation/FlocculationStirred tanks tanks in series recycle reactors Removal of particulates with alum Removal of humic compounds with ferric chloride Lime softeningStirred tanks recycle reactor Removal of calcium with lime Air strippingPacked column Bubble tanks CO 2 removal NH 3 removal Flow Reactor: Examples of flow reactors

 Conservation of Mass… [Accumulation] = Q, C o Q, C 1 V System boundary Flow Reactor: Materials Balances

Material Balances (cont.)  If the reaction is first-order, r = -kC 1, the balance becomes  Steady-state – no accumulation within the system  Transient state – rate of accumulation is changing with time

Material Balances (cont.)  Assuming steady-state (Q = V/Q):

C A0 C A1 Q Q dV Plug-Flow Reactor (PFR)  Water flows uniformly without mixing  The performance of PFR is the same as CMBR operated for the same period of time

 The materials balance around the volume element dV… QC A = Q(C A - dC A ) + r A dV Q dC A = r A dV  Consider a plug-flow reactor with first-order reaction: r A = -kC A  which can be integrated for a first-order kinetic as follows C A0 C A1 Q Q dV Plug-Flow Reactor (PFR)

PFR Batch PFR provides a hydraulic residence time equal to the time required to accomplish the conversion in a batch reactor C A0 C A1 Q Q dV C A1 V Comparison between PFR and CMBR

MASS BALANCE -Addition Q o, C o Q 2, C 2 Q 1, C 1

MASS BALANCE - Separation  Mass balance for water flow Q f = Q c + Q p  Mass balance for solute flux Q f C f = Q c C c + Q p C p  Product recovery r = (Q p /Q f )·100%  Constituent rejection R= ((C f - C p )/C f )·100% = (1 - C p /C f )·100%