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INSTITUT CATALÀ DE RECERCA DE L’AIGUA (ICRA)

1

LEARNING OBJECTIVES

1. WHY ADVANCED TREATMENT?

2. CONTAMINANT PROPERTIES AND CHOICE OF TREATMENT

3. OPTIONS FOR ADVANCED TREATMENT – FATE OF MICROPOLLUTANTS

4. ASSESSING AND EMBEDDING A TECHNOLOGY IN A TREATMENT TRAIN


Aims of (waste)water treatment

To produce fit-for-purpose water quality, meaning the control of water

quality hazards to yield an acceptable level of risk, whereby

risk = frequency x probability of adverse outcome x severity of effect

Risk can refer to public health, financial, reputational, environmental,

social…


Fit-for-purpose water quality

Water quality that is appropriate, and of a necessary standard, for its intended use.

“Don’t crack a nut with a sledgehammer!”

Example: Typical recycled water end-uses:

- Augmentation of Drinking Water Supplies

- Managed Aquifer Recharge

- Dual reticulation indoor (toilet, laundry)

- Dual reticulation outdoor (irrigation, car washing,…)

- Municipal irrigation (controlled / uncontrolled)

- Agriculture (different quality depending on crop)

- Fire fighting

- Commercial (dust suppression, cooling water)

- Replacement of environmental flows

Level of treatment depends on initial water quality and end-use!


D. Sedlak (2014), Water 4.0: The Past,

Present, and Future of the World’s Most

Vital Resource, 352p. Yale University Press.

Pre-human development






Water 1.0 Supply and Drainage







Water 2.0 Water Treatment








Water 3.0 Wastewater Treatment


Water scarcity and strife for

efficiency gains create a

diversity of source and target

water qualities.








Water 4.0 Diversity of Supply


Opportunities and need for

alternative treatments that

MAY also be “ADVANCED”.

Water scarcity and strife for

efficiency gains create a

diversity of source and target

water qualities.








Water 4.0 Diversity of Supply

LEARNING OBJECTIVES






• Liquid but certain viscosity

• “heavy”, 1L = 1kg (approx.)

• Non-compressible

• Transparent

• Polar, dielectric fluid, H-bonds

• Dissolves well polar organic and many

inorganic substances

• Dissolves gases to some extent, some

polar gases are dissolved very well

• Surface tension, capillary action

• Heat capacity 4.184 J/g.K

• Enthalpy of vaporization, 2260 kJ/kg

• Vapour pressure f(T), 23mbar @ 20°C

• Abundant on earth?

Water – H2O


Of, relating to, or denoting compounds containing carbon (other

than simple binary compounds and salts) and chiefly or ultimately

of biological origin

Of, relating to, or denoting compounds that are not organic

(broadly, compounds not containing carbon)

Organic substances

Inorganic substances

Biological material

Any material containing genetic information and capable of

reproducing itself or being reproduced in a biological system.

Contaminant classification


Contaminants – only some examples…

temperature

Total organic

carbon (TOC)

Chemical oxygen

demand (COD)

Biological oxygen

demand (BOD)

Heterotrophic plate

count (HPC)

Suspended solids

Colour

turbidity

Organic

micropollutants

Humic substances

Dissolved mercury,

other toxic metals

Human adenovirus

Total phosphorus

nitrate, ammonium

salt

Cryptosporidium spp

Salmonella, E.coli

Disinfection

byproducts


Biological contamination: pathogens Disease causing microorganisms are called pathogens.

But there are a lot of “good microorganisms”. According to a recent National Institutes

of Health (NIH) estimate, 90% of cells in the human body are bacterial, fungal, or

otherwise non-human. http://mpkb.org/home/pathogenesis/microbiota

http://mpkb.org/home/pathogenesis/microbiota

Size matters… e.g. for filtration processes



Vapour pressure: Easy to oxidize / reduce?

Electrical charge: Solubility:

Hydrophobicity/hydrophilicity: Biodegradability:

Size:


Vapour pressure: • Air stripping

• Distillation

Easy to oxidize / reduce?

• Ozonation, advanced oxidation

• Chlorination and chloramination

• Metal finishing

• Coagulation

• Reverse & forward osmosis

• Electrodialysis

Electrical charge: Solubility:

• Precipitation

• Adsorption

Hydrophobicity/hydrophilicity: • Adsorption

• Extraction

• Coagulation

• Secondary treatment

• Reverse & forward osmosis

Biodegradability: • Primary and secondary wastewater

treatment, MBR

• biofiltration

Size: • Filtration processes

• Adsorption

FURTHER READING

David Sedlak (2014), Water 4.0: The Past, Present, and Future

of the World’s Most Vital Resource, 352p. Yale University Press.

John C. Crittenden, R. Rhodes Trussell, David W. Hand, Kerry J.

Howe, George Tchobanoglous. (2012). MWH's Water Treatment:

Principles and Design, Third Edition.

Guidelines for drinking-water quality, fourth edition. World Health

Organization (2011).

http://www.who.int/water_sanitation_health/publications/2011/dw

q_guidelines/en/index.html

http://www.who.int/water_sanitation_health/publications/2011/dwq_guidelines/en/index.html



LEARNING OBJECTIVES




MEMBRANE FILTRATION

ADSORPTION

(ADVANCED) OXIDATION PROCESSES

BIOLOGICAL TREATMENT, DISTILLATION


MEMBRANE FILTRATION - OVERVIEW

APPLIED FULL SCALE ROUTINELY

1. Pressure driven: microfiltration (MF), ultrafiltration (UF), nanofiltration (NF),

reverse osmosis (RO)

2. Charge separation: Electrodialysis (ED), electrodialysis reversal (EDR)

PILOT / DEMONSTRATION SCALE

3. Osmotic processes: Forward osmosis (FO), pressure retarded osmosis

(PRO), pressure assisted forward osmosis (PAO)

4. Thermal separation: Membrane distillation (MD)

PRESSURE DRIVEN MEMBRANE FILTRATION

Microfiltration Ultrafiltration Nanofiltration Reverse

osmosis

PORE SIZE (μm): 0.05 – 10 0.01 – 0.05 <0.005 <0.002

FLOW (L/m2.h)1: 40 – 150 20 – 60 10 – 30 10 – 30

PRESSURE (bar): 0-1 0-5 2-15 5-75

Rejects well2: Solids, bacteria,

protozoa

Virus,

macromolecules

Polyvalent salt,

OMP

Monovalent salt,

OMP

Materials3: PVDF, PTFE, PES, PS, ceramic, etc Fully crosslinked aromatic polyamide

in thin-film composite membrane

(PES, PE support)

Operational

aspects:

Fouling/Scaling, hydraulic

backwashing & chlorine cleaning

possible

Fouling/Scaling, need good

pretreatment, not resistant to oxidants,

no hydraulic backwash possible

1 rapid sand filter: approx 10’000 L/m2.h, river bank filtration 200-1’000 L/m2.h

2 as pore size decreases, of course also larger solutes are rejected mentioned to the left in the table

3 PVDF: polyvinidylfluoride; PTFE: polytetrafluoroethylene; PES: polyethersulfone; PS: polysulfone; PE: polyester

PRESSURE DRIVEN MEMBRANE FILTRATION

REJECTION MECHANISMS IN NF/RO


RO

Concentrate

Feed 1 Feed 2 Feed 3

Total Permeate Permeate 1

Permeate 2 Permeate 3

PV 2

PV 3

PV 4

PV 1

PV 2

Stage 1 Stage 2 Stage 3

1 Train

PV 1

PV 1

PV = Pressure Vessel

RO Train: 4:2:1 configuration of pressure vessels (PV)

On-line conductivity measure


RO membranes are not simply ‘molecular sieves’ but complex working filters

~ 0.1 µm

Frequently, so-called “solute-diffusion” model

used to model rejection


Bellona et al., Water Res. 38 (2004) 2795-2809.

REJECTION BY NF/RO - pharmaceuticals

Rejection with virgin RO membrane at pilot-scale and bench-scale

Lower rejection with spiral wound membrane at pilot-scale Higher recovery & Lower cross-flow velocity towards the end of the pressure vessel

Enhanced concentration polarization

Source: Chrystelle Ayache (2013). PhD thesis. The University of Queensland.

REJECTION BY NF/RO – disinfection byproducts

Source: Doederer et al (2014). PhD thesis. The University of Queensland.

0

10

20

30

40

50

60

70

80

90

100

DB

P r

eje

ction

(%

)

RO

NF

REJECTION BY NF/RO – process parameters: T

Source: Doederer et al (2014). PhD thesis. The University of Queensland.

0,E+00

1,E-11

2,E-11

3,E-11

wa

ter

pe

rme

ab

ility

(m

) ↑ pore size

0

20

40

60

80

100

20 30 40

DB

P r

eje

ctio

n (

%)

Temperature (oC)

BDCM

BDIM

BCAN

1,1-DCP

0,0

0,5

1,0

1,5

2,0

2,5

70 80 90 100 110 120

Re

jectio

n r

atio

23

oC

/35

oC

-1

Molecular volume (Å3)

↑ solute diffusivity ↑ partitioning

REJECTION BY NF/RO: SUMMARY

• Rejection mechanisms: 1) size exclusion; 2) charge

interaction; 3) hydrophobic interaction

• % Rejection can be very high, often 90-99.5% (RO > NF)

• Small hydrophilic compounds not well rejected, e.g. boric acid,

nitrosodimethylamine (NDMA) sometimes 0-50%

• Hydrophobic compounds can also be problematic, particularly

when “cake-enhanced concentration polarization” occurs.

• Flow, temperature, fouling influence rejection %

• Many other water quality benefits: salinity, solids, pathogens

• Concentrate management can be a problem

MEMBRANE FILTRATION - OVERVIEW

APPLIED FULL SCALE ROUTINELY

1. Pressure driven: microfiltration (MF), ultrafiltration (UF), nanofiltration (NF),

reverse osmosis (RO)

2. Charge separation: Electrodialysis (ED), electrodialysis reversal (EDR)

PILOT / DEMONSTRATION SCALE

3. Osmotic processes: Forward osmosis (FO), pressure retarded osmosis

(PRO), pressure assisted forward osmosis (PAO)

4. Thermal separation: Membrane distillation (MD)

ELIMINATION OF OMP BY ELECTRODIALYSIS

https://youtu.be/wvS7jsIhGBQ

https://www.gewater.com/products/electrodialysis-reversal-water-treatment

How does ED(R) work?

Nice video from General Electric on youtube:












ELIMINATION OF OMP BY ELECTRODIALYSIS

Drinking water treatment – pilot plant EDR process

Llobregat river: 50 organic micropollutants detected

Removal up to 60% of the EDR process for charged compounds

no effect was observed for neutral compounds

For comparison: approximately 70-85% of inorganic ions are removed

Source: Gabarrón et al. J. Hazard. Mater. 309 (2016) 192-201.

ELIMINATION OF OMP BY FORWARD OSMOSIS

High

concentration (osmotic agent,

draw solution)

Low

concentration (feed solution)

McCutcheon et al. JMS, 278 (2006) 114.

Because of internal concentration polarization new, thinner membranes needed

with open support structure.

ELIMINATION OF OMP BY FORWARD OSMOSIS

Example of integration of FO or PRO with seawater desalination for direct potable reuse:

Kim et al. Desalination, 322 (2013) 121-130.

• In application, potentially a doublé barrier against micropollutants

compared to traditional MF-RO approach in potable reuse applications.

• Because of membrane characteristics (thin, high permeability) rejection

is somewhat lower than for RO membranes.

• Similar to NF big differences among membranes on the market.

FURTHER READING

Bellona et al., Factors affecting the rejection of organic solutes

during NF/RO treatment—a literature review. Water Res. 38 (2004) 2795-2809.

Arne Verliefde (2008). Rejection of organic micropollutants by high pressure membranes

(NF/RO). PhD Thesis, TU Delft.

http://www.citg.tudelft.nl/fileadmin/Faculteit/CiTG/Over_de_faculteit/Afdelingen/Afdeling_

watermanagement/Secties/gezondheidstechniek/leerstoelen/Drinkwater/Research/Compl

eted_PhD_projects/doc/PhD-Thesis_ARD_Verliefde.pdf

Doederer et al., Rejection of disinfection byproducts by RO and NF membranes:

Influence of solute properties and operational parameters. J. Memb. Sci. 467 (2014) 195-

205.

Vanoppen M. et al, Properties governing the transport of trace organic contaminants

through ion-exchange membranes. Environ. Sci. Technol. 49(1) (2015) 489-497.

Gabarrón S. et al, Evaluation of Emerging Contaminants in a Drinking Water Treatment

Plant using Electrodialysis Reversal Technology. J. Hazard. Mater. 309 (2016) 192-201.

Coday B.D. et al, Rejection of trace organic compounds by forward osmosis membranes:

A literature review. Environ. Sci. Technol. 48(7) (2014) 3612-3624.

Other manuscripts cited on previous slides

http://www.citg.tudelft.nl/fileadmin/Faculteit/CiTG/Over_de_faculteit/Afdelingen/Afdeling_watermanagement/Secties/gezondheidstechniek/leerstoelen/Drinkwater/Research/Completed_PhD_projects/doc/PhD-Thesis_ARD_Verliefde.pdf







LEARNING OBJECTIVES




MEMBRANE FILTRATION

ADSORPTION



ADSORPTION

Adsorbent Technology Application

Granular Activated

Carbon (GAC)

Fixed bed, e.g. filter Organics removal (bulk and

micropollutant)

Biological Activated

Carbon (BAC)

Fixed bed, e.g. filter Organics removal (bulk and

micropollutant), often after

oxidation process to remove

biodegradable matter

Powdered Activated

Carbon (PAC)

Dosed in suspensión,

needs removal, often

applied temporarily as

emergency response to

contamination

Organics removal (bulk and

micropollutant), often to combat

seasonal taste & odour problems

in WTP

Zeolites Both, suspended and

fixed bed

Ion exchange, softening, heavy

metals

Ion exchange resins Suspended, need

regeneration

Ion Exchange, softening, natural

organic matter removal

Novel materials:

carbón nanotubes,

graphene oxide, etc

Diversity of tailored surfaces, adsorbents, applications,

ADSORPTION – example GAC full scale

Source: Gabarrón et al. J. Hazard. Mater. 309 (2016) 192-201.

ADSORPTION – example: 3 full scale BAC

Source: Reungoat et al. Water Res. 46 (2012) 863-872.

BAC bed age:

Caboolture: 2.5 y, 68’000 beds

Landsborough: 8 y, 350’000 beds

Gerringong: 50% of media: 8y,

95’000 beds, 50% 1y, 13’000 beds

ADSORPTION – example: 3 full scale BAC


ADSORPTION – summary

• Removal can be high, >90%, particularly on fresh GAC

• Adsorption depends on molecule charge / hydrophobicity – i.e. negative

or hydrophilic compounds break through earlier or are hardly adsorbed

on carbon (e.g. iodinated constrast agents)

• Adsorption is an equilibrium process with desorption – high spikes can

be well mitigated, during times of low influent concentration desorption

may occur.

• Re-activation / renewal of carbón and civil works are major cost factors,

otherwise low direct energy consumption compared to oxidation and

membrane filtration processes

FURTHER READING

Gabarrón S. et al, Evaluation of Emerging Contaminants in a Drinking Water Treatment

Plant using Electrodialysis Reversal Technology. J. Hazard. Mater. 309 (2016) 192-201.

Reungoat J. et al, Ozonation and biological activated carbon filtration of wastewater

treatment plant effluents. Water Res. 46 (2012) 863-872.

Rattier M., Reungoat J., Gernjak W., and Keller J. (2012), Organic Micropollutant

Removal by Biological Activated Carbon Filtration: A Review. Urban Water Security

Research Alliance Technical Report No. 53.

http://www.urbanwateralliance.org.au/publications/UWSRA-tr53.pdf

Jingyi Hu (2016). Micro-pollutant removal from wastewater treatment plant effluent by

activated carbon. PhD thesis, Delft University of Technology.

http://www.citg.tudelft.nl/fileadmin/Faculteit/CiTG/Gezondheidstechniek/doc/Proefschrifte

n/Jingyi_Hu_-_Micro-

pollutant_removal_from_wastewater_treatment_plant_effluent_by_activated_carbon.pdf

David de Ridder (2012). Adsorption of organic micropollutants onto activated carbon and

zeolites. PhD thesis. Delft University of Technology.

http://repository.tudelft.nl/islandora/object/uuid%3A36768caf-ba11-45b8-9d71-

b6ebbf5cc9e8?collection=research

John C. Crittenden, R. Rhodes Trussell, David W. Hand, Kerry J. Howe, George

Tchobanoglous. (2012). MWH's Water Treatment: Principles and Design, Third Edition.






http://www.citg.tudelft.nl/fileadmin/Faculteit/CiTG/Gezondheidstechniek/doc/Proefschriften/Jingyi_Hu_-_Micro-pollutant_removal_from_wastewater_treatment_plant_effluent_by_activated_carbon.pdf







http://repository.tudelft.nl/islandora/object/uuid:36768caf-ba11-45b8-9d71-b6ebbf5cc9e8?collection=research










LEARNING OBJECTIVES




MEMBRANE FILTRATION

ADSORPTION



OXIDATION – Theory and Processes

Reduction - augment number of electrons in molecule

Oxidation - reduce number of electrons in molecule

Source: Braun et al. Chem. Rev. 93(2) (1993) 671-698.

Wid

ely

ap

plied

in

wate

r in

du

str

y


A number of other oxidants, e.g. electron holes in valence band of semiconductors.

Also reductants can be interesting:

• electrons in conduction band of semiconductors or solvated

• Hydrogen atoms, nascent hydrogen

Advanced oxidation processes defined as those generating hydroxyl radicals,

but often not the only mechanism. They have sparked particular attention in

research, although not so many applications other than ozone and UV/H2O2 in

relatively clean water, some Fenton applications in industrial wastewater.

Many good and exhaustive reviews, e.g.:

Braun et al, Chem. Rev. 93(2) (1993) 671-698.

Gogate and Pandit, Adv. Environ. Res. 8 (2004) 501-551.


Pignatello et al, Crit. Rev. Env. Sci. Technol. 36 (2006) 1-84.

Malato et al, Catal. Today 147(1) (2009) 1-60.


Conventional and industrially applied oxidation processes:

HOCl: chiefly employed as disinfectant, inconvenience of generating halogenated

disinfection byproducts (DBPs)

NH2Cl: disinfectant for distribution, fewer DBPs, but e.g. NDMA formation.

ClO2: disinfectant or pre-oxidation before HOCl to reduce DBP formation, but

forms chlorite.

O3: cheap, energy efficient, good removal for many electron rich contaminants,

generates bromate in bromide rich waters

UV/H2O2: more expensive, higher cost/energy compared to O3, no byproduct/

bromate formation

All oxidation processes generally only transform molecules but don´t

mineralize! Even if a process is capable of mineralizing, doing so would be

uneconomical in most situations.


Advanced oxidation processes

UV-C/H2O2: mostly •OH reaction pathways

O3: mix of ozone and •OH reaction pathways, addition of H2O2 and/or UV-C and/or

raising pH can promote • OH generation.

Fenton & photo-Fenton (with UV or solar): wide variety of conditions, typically

pH=3, sludge generation. Mix of reactions, e.g. also photolysis of iron-

organic complexes

Semiconductor photocatalysis (UV-A or solar): suspension or immobilised – both

with respective trade-offs. A lot of materials research on photocatalyst

development, TiO2 remains the standard. Inherently low quantum

efficiency due to prevalent electron – hole recombination. Much

research (>40’000 papers) – Little application.

Electrochemical oxidation: Existing applications rely on mediated oxidation (e.g.

generate HOCl from Cl- in situ), sulfate as mediator “hot topic”,

electrode and reactor development required. Also direct oxidation.

Sonolysis & Hydrodynamic cavitation: generate bubbles that collapse generating

high temperature & pressure in minute space. Complex chemistry

(e.g. water splitting). Energy intensive.


More (advanced) oxidation processes

Non-thermal equilibrium plasma: energy intensive, complex chemistry, little understood

Vacuum UV: direct water splitting, complex chemistry

Electron beam treatment: often used as reference AOP – only • OH generated.

Wet oxidation

Supercritical oxidation

Persulfate/UV or Persulfate/UV/Fe

Photo-electro Fenton, photoelectrocatalysis

etc.


Some general considerations:

1) Pollutants occur usually homogeneously distributed

• Hence a process acting across entire volume often more efficient, especially

important for disinfection where 99-99.99% inactivation is typically desired.

• Local generation of reactive species creates important challenges for reactor

design to overcome mass transfer limitations.

• In light-driven processes, increase in wavelength will increase penetration

depth.

• Competition among pollutants, scavenging capacity, and radical

recombination, e.g. how many of my photons trigger the “right” reaction? How

many of the reactive species react with pollutants?

• Hence, deeper light penetration and longer wavelength are only then

favourable, if the ratio of desired/undesired reactions increases.


2) Reactive species will have different lifetimes from ns to days. Consider the

importance for mass transfer.

• E.g. typically velocities in strongly mixed reactor are in the range of m/s. If

lifetime is 10 ns and speed is 10 m/s, lifetime “distance” is 0.0001mm. Often

the strongest oxidant will not be the best, particularly if generated

heterogeneously across the solution.

3) Energy efficiency in oxidation processes is in the end about minimizing

undesired losses.

• UV/H2O2: Conversion of electricity into light – typical efficiencies are between

15% (medium pressure Hg lamps) and 40% (low pressure Hg lamps). Then

conversion of light to chemically useful species/energy. Yield% of useful

reactions.

• Sonolysis: Conversion of electrical energy into mechanical energy,

mechanical energy into chemical energy. Yield% of useful reactions.

• O3 or HOCl: Synthesis of oxidant. Yield% of useful reactions.

To compare processes: “Electrical energy per order of contaminant decrease”

Source: Bolton et al. Pure Appl. Chem. 73(4) (2001) 627-637.


• A lot of (advanced) oxidation processes, but only few are really applied broadly.

Others only applied in research or niche applications.

• Many processes generate a mix of reactive species.

• Water chemistry (matrix) and treatment objective will define the fit-for-purpose

application.

• Homogeneous versus heterogeneous reaction systems taking into account

oxidant lifetime and mass transfer.

• (Electrical) energy per order of contaminant transformation typical figure-of-

merit.

• Oxidation rather transforms organic contaminants instead of mineralizing them.

• Most organic contaminants can be treated by AOPs (fewer by conventional

oxidation) – the questions is which is the process least costly, energy intensive,

does not generate undesired secondary contamination, by-products, most

safe, resilient etc.

• Some exceptions exist, e.g. polyfluorinated compounds, but most react simply

more or less rapidly, i.e. treatment becomes more or less effective.

Summary:

OXIDATION – Some applications


Tertiary treatment with O3/BAC for

subsequent water reuse.



Generally good removal % - these treatment plants employ actually

a low to médium O3 dose.


Source: Lee et al. Env. Sci. Technol. 50 (2016) 3809-3819.

Comparison of several processes, including energy and byproducts

OXIDATION – Issue of transformation products

Toxicity is a general term applied to different non-specific and specific

biologically adverse effects.

Specific effects (e.g. estrogenicity) almost always decrease after a target

molecule has been transformed.

Non-specific effects (e.g. baseline toxicity, mutagenicity, oxidative stress) may

increase after transformation of target molecule.

In most cases, despite a possible initial increase of a biologically adverse effect

upon oxidation, further transformation decreases again toxicity need to

understand a specific application (water to be treated + technology applied).

Often, oxygen inserting oxidation technologies generate reactive aldehydes or

quinones that increase toxicity.

These transformation byproducts are however often quite biodegradable, i.e.

not an issue in a properly designed treatment train. See e.g.

de Vera et al. Water Res. 106 (2016) 550-561.

Escher et al. J. Environ. Monitor. 11(10) (2009) 1836-1846.

Macova et al, Water Res. 44(2) (2010) 477-492.


Nevertheless, transformation products can be an issue.

Examples of known toxic transformation products:

Triclosan photolysis (also in the environment) can generate dioxins.

Latch et al. J. Photochem. Photobiol. A: Chem. 158(1) (2003) 63-66.

Generation of halogenated byproducts with HOCl and related toxicity.

De Vera et al. Water Res. 87 (2015) 49-58.

Farré et al. Water Res. 47(14) (2013) 5409-5421.

Generation of other byproducts NDMA (monochloramine), bromate (ozone),

chlorite (chlorine dioxide)…

Certainly some more could be cited…

Although only few examples with a clear issue are known, it is

hard to deal with known unknowns from a risk based approach

(which is how water managers take their decisions).


Studying transformation pathways can help to understand a

specific problem, but is not a generally applicable solution

(too many compounds, too many processes).

Radjenovic et al.

Environ. Sci. Technol. 46

(2012) 8356-8364.

FURTHER READING

International ozone association

http://www.ioa-pag.org/

International UV association

http://www.iuva.org/

Von Sonntag C. and von Gunten U. (2012). Chemistry of Ozone in Water and

Wastewater Treatment. 320p. IWA Publishing. ISBN: 9781843393139.

Bas Wols (2010). CFD in in drinking water treatment. PhD Thesis. TU Delft.

http://repository.tudelft.nl/islandora/object/uuid%3Ab1d4405e-a364-4105-ab03-

21800b46df5b?collection=research

B. Escher and F. Leusch (2011). Bioanalytical Tools in Water Quality Assessment. 272p.

IWA Publishing. ISBN: 9781843393689.

Review manuscripts on AOPs:

Braun et al, Chem. Rev. 93(2) (1993) 671-698.



Pignatello et al, Crit. Rev. Env. Sci. Technol. 36 (2006) 1-84.

Malato et al, Catal. Today 147(1) (2009) 1-60.

Other manuscripts cited on previous slides







http://repository.tudelft.nl/islandora/object/uuid:b1d4405e-a364-4105-ab03-21800b46df5b?collection=research










LEARNING OBJECTIVES




MEMBRANE FILTRATION

ADSORPTION



DESIGNING A TREATMENT SOLUTION

1. Description of project need & opportunity

2. Source water characterization & definition of target water quality

3. Definition of treatment objectives (inorganic, chemical, biological) & constraints

(e.g. financial, energy consumption, mínimum water recovery)

4. Sketch out options for treatment trains

5. Cost-benefit analysis (multidimensional analysis, economic-

environmental-social)

6. Design & Operation guidelines

7. Performance validation & verification

3. Sketch out options for treatment trains – consider redundancy &

multi-barrier approaches

Example:

• Scheme A: 1 treatment process with 4-log removal

• Scheme B: 2 independent, sequential treatment processes with 2-log removal,

total max 4-log removal

• Assume that each process has 99% reliability and fails completely 1% of time

Scheme A Scheme B

4-log removal 99% 98.01%

2-log removal - 1.98%

0-log removal 1% 0.01%


3. Sketch out options for treatment trains – consider redundancy

All risks and contaminants must be adequately addressed, some examples of

treatment trains for potable reuse can be found here:

Gerrity et al (2013), J. Wat. Supply: Res. Technol. – AQUA, 62(6) (2013) 321-338.

Some tricky questions:

• How to deal with residual water quality risk or other uncertainties?

• Multi-criteria optimization always needed, weighting in decision process may not solely

based on human health or technical criteria

• Stakeholder engagement – when and how much?


LEARNING OBJECTIVES




MEMBRANE FILTRATION

ADSORPTION



SOME KEY PHRASES

• Opportunities for advanced treatment arise from water supply source

diversification and new internal recycle loops.

• Treatment is defined by source and required final water quality.

• Water and contaminant properties will clearly influence the choice of a treatment

train and its performance.

• Many technologies are researched, only few applied – there may be a reason

behind this ;-).

• RO/NF membranes are not simple filters – other properties than size do matter

as well.

• Adsorption is relatively energy efficient and can mitigate contamination spikes.

Contaminant hydrophobicity and charge are important.

• In oxidation consider trade-offs between oxidant strength and life-time.

• Oxidation transforms contaminants rather than removing them. This may be a

problem. Also, other byproducts may be formed (e.g. bromate).

• Consider that each treatment step is always part of a train.

• Implementation may require tricky non-technical questions to be solved.

INSTITUT CATALÀ DE RECERCA DE L’AIGUA (ICRA)

Wolfgang Gernjak ICREA Research Professor ICRA - Institut Català de Recerca de l'Aigua / Catalan Institute for Water Research Carrer Emili Grahit,101 Edifici H2O E- 17003 Girona (Spain) Tel: (+34) 972 18 33 80 Fax: (+34) 972 18 32 48 [email protected], www.icra.cat, www.icrea.cat http://orcid.org/0000-0003-3317-7710

mailto:[email protected]

http://www.icra.cat/

http://www.icrea.cat/

http://orcid.org/0000-0003-3317-7710

http://orcid.org/0000-0003-3317-7710

http://orcid.org/0000-0003-3317-7710

http://orcid.org/0000-0003-3317-7710

http://orcid.org/0000-0003-3317-7710

http://orcid.org/0000-0003-3317-7710

http://orcid.org/0000-0003-3317-7710

http://orcid.org/0000-0003-3317-7710

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