Â

Contaminants in Water

Melbourne 2004

Presenter - Mike Finney

Millipore AustraliaLaboratory Water Division

ÂÂ

Ground & Surface Water

Surface Water- Higher in biological material.

- Higher in particulates

- Lower in dissolved ions

Ground Water- Higher in dissolved ions

- Low in particulates

- Low in biological Material

ÂÂ

Tap Water Contaminants

+- SALTS

ORGANICS

PARTICLES / COLLOIDS

MICROORGANISMS

DISSOLVED GASES

ÂÂ

Common salts in Tap waterANIONS CATIONS

Na + Ca + +

Al+ + +

Mg+ +

Fe+ +

Pb+

CO

Cl - NO3-

4PO---

SO4--

3-- ClO-

SiO4

Si2O 7 ...... SiO2

ÂÂ

Organic Solutes (natural)

TANNINS

HUMIC ACIDS

FOLIC ACIDSLIGNIN

PYROGENS

PHENOLSHO

HO

HO COOR

HO CH CHCOOH

OH

RR

R

R R

ÂÂ

Organic Solutes (artificial)

HERBICIDES INSECTICIDESORGANOCHLORINE

PAH PHTALATESPCB

CHCl 3

CCl 4

Cl

H3C-CH-CH3

N

NN

N NCH3-CH2

HHCl N

OP(OCH2CH3)2

Cl Cl

SCH Cl22

Cl

Cl

Cl

Cl

ClC C

O O

RO OR

ÂÂ

Particles and Colloids

-

--

-

--

- --

-

-

--Hard or Soft Particles :

a protection for bacteriaand a nuisance in labexperimentation

Colloids :stable suspension of inorganic or organic particles

ÂÂ

Bacteria

Staphylococcus Aureus Serratia Marcescens

ÂÂ

Pyrogens

Pyrogens (also calledendotoxins, i.e. “toxinsfrom the inside)are lipopolysaccharides (LPS) from the wall of Gram Negative bacteria.They have anhydrophilic (polysaccharide) and hydrophobic (lipid) part.Pyrogens (from the Greek πυρ = fire, because they inducefever) can withstand autoclaving procedures (3 h at 121°C), although exposure for 4 hours at 180°C reduces the pyrogen concentration by a factor 1,000 (LRV = 3).

ÂÂ

Rnase

ÂÂ

RNases

Ribonucleases are enzymes responsible for the degradation of ribonucleic acids (RNA).They cut single stranded RNA at designated base sites.Picogram quantities are enough to degrade RNA.These proteins with MW between 10,000 and 30,000 Dalton are omnipresent,can withstand high temperature (up to 100°C), extreme pH and remain active for weeks.They can be isolated from microbial, fungal or mammalian sources.Detection: by RNA hydrolysis (agarose gel + blotting or by test kit (Ambion).

ÂÂ

Gases

OxygenNitrogen

CarbonDioxide

Radon

Â

Water Purification Techniques

ÂÂ

Water Purification Techniques

+-

Contaminant Removal By

Still DI EDI RO UF MF AC UV 254185

ÂÂ

Particle Size and Separation Techniques

1000µm 100µm 10µm 1µm 0.1µm 0.01µm 0.001µm

50µm

SewingNeedle’s

EyeRazor bladeThickness

HumanHair

LiverCells

Chloroplaste

Red BloodCells

E. ColiPseudomonasdiminuta

Mycoplasma

Adenovirus

Poliovirus

Glutamate DHDehydrogenase(MW =1 000 000)

Hemoglobin(MW =65,000)

Insulin(MW = 6,000)

Glucose(MW=180 D)

Clarification Microfiltration Ultrafiltration ReverseOsmosis

ÂÂ

Distillation

Removes a large percentage of all types of contaminantsProduces water with resistivity between 0.2 and 1 Megohm.cmAverage investmentWell known and perceived as easy to operate

Not all contaminants are removed and several are generated during the processNo control of water qualityHigh operating costs due to electric heating (0.8KW/L) and water cooling (15 L/L)Regular maintenance (acid cleaning) or pretreatment (DI) is actually required to ensure optimum performance

ÂÂ

Deionisation (DI)

Effective at removing ions (Resistivity : 1 - 10Megohm.cm)

Does not eliminate particles, organic materials or microorganisms. Limited capacity depending on binding sites density and accessibility : requires good quality feed water to prevent premature exhaustion.Capacity related to flow rate

ÂÂ

ElectroDeIonisation (EDI) Module

ÂÂ

ElectroDeIonisation (EDI)

Very efficient removal of ions and small MW charged organic (R> 5 Megohm.cm)Low energy consumptionHigh water recoveryLow operating costLow maintenanceNo particulates or organic contamination (smooth, continuous regeneration by weak electric current)Moderate investment

Requires good quality (RO) feed water to prevent plugging (particulates), fouling (organic, colloids) of ion-exchange resin beads and scaling at cathode.CO2 not totally removed if at high level in feed water.

ÂÂ

Reverse OsmosisOsmosis Reverse Direct Osmosis

Two branches of a U tube are separated by a membrane permeable only to water molecules. If a solute is dissolved in the left branch, water molecules will go through the membrane to dissolve the solute.

ÂÂ

Reverse Osmosis

P P

Reverse Osmosis is the oppositeof Direct Osmosis: pressure isapplied on the solution, and pure water goes throughthe semi-permeable membrane.

Reverse Osmosis

ÂÂ

Reverse Osmosis

Removes a fair percentage of all types of water contaminantsLow energy consumptionLow operating costWater consumption 1-4 times less than stillsNo need for strong acids or bases for cleaning so low maintenance requirementsGood control of operating parameters

RO membranes are subject to plugging, fouling, piercing and scaling if not properly protected and maintainedNot enough contaminants removed to satisfy Type II requirements

ÂÂ

Ultrafiltration

Effective removal (>99%) of all organic molecules with molecular weight above the NMWL. Very efficient at removing pyrogens and viruses as well as particles.No risk of scaling ; limited risk of fouling.Low use of water and energyLow maintenance ; procedures well documented / accepted.

Almost no rejection of ions, gases and low molecular weight organics (tightest UF membranes have a 1,000dalton cut-off

ÂÂ

Membrane Microfiltration

100 % removal of all contaminants (particulates, bacteria)larger than pore size. Integrity test availableSterilizing filtration (0.22 um membranes - LRV > 7)Minimum maintenance : simply replace when required.High flow rates are achievable at low pressureEfficiency independent of flow rate.

Minimum effect on other contaminantsSurface retention : may be subject to fouling/ plugging

ÂÂ

Activated Carbon

Effective removal of a large range of organic substances (even of low molecular weight) by non specific binding (Van der Waals forces)Large capacity due to high developed surface

Very little effect on other contaminants (except someparticulates removed by depth filtration)Once all active sites are occupied, an equilibrium is established and organicsare released.Bacteria may develop after several months.Efficiency depending on flow rate

ÂÂ

UV: Electromagnetic Spectrum

Gamma rays X Rays U.V. Visible Infrared

Ultraviolet radiation

Wavelength(m)10-10 10-7 10-6 10-4 10-3

100 200 280 315 400Wavelength (nm)

Ultra short Short Medium Long wave UV-C UV-B UV-A

ÂÂ

UV Technology (185 + 254 nm)

Conversion of traces of organic contaminants to charged species and ultimately CO2 (185 + 254)Limited destruction of micro-organisms and viruses (254)Limited energy useEasy to operate

Polishing technique only: may be overwhelmed iforganics concentration in feed water is too highOrganics are converted, not removed.Limited effect on other contaminantsGood design required for optimum performance.

ÂÂ

Technologies & Contaminants Removal

STILL DI RO UF MF AC UV

IONS

ORGANICS

PARTICLECOLLOIDSBACTERIA

GASES

Contaminant still 100% present (not removed)Contaminant completely (100%) removed

Â

Water Contaminant Monitoring

Ionic Contaminant Detection by Conductivity / Resistivity

Organic Contaminant Detection by TOC Analysis

Â

Ionic Contaminant Detection

ÂÂ

How to measure salt concentration ?Chemical analysis for detection of specific ions. The method will depend on the required sensitivity (i.e. which concentration do we want to detect : ppm ? ppb ? ppt ?)1 ppm (1 mg/L) 1 second in 11.5 days1 ppb (1 µg/L) 1 second in 32 years1 ppt (1 ng/L) 1 second in 317 centuries

Conductivity or resistivity allows to detect the “global” salt contamination in water. It is based on the fact that water has a relatively high electric resistance. When electric current goes through water, it is carried out almost only by ions.

Â

Organic Substance Detection

ÂÂ

TOC = Total Organic CarbonTotal Oxidisable Carbon

Tap water, the ‘raw material’ used to produce pure water for laboratory applications may contain many different oxidisable carbon substances, mainly dissolved.

TOC in Water

ÂÂ

TOC : Concept

TOC measurement is a way of normalising the amount of carbon containing compounds in water.

Water may contain hundreds of different organic substances at different levels of oxidation, and at different concentrations.TOC monitoring will express the organic contamination of water with a single figure.

ÂÂ

Why test for TOC ?

Quality & Reliability of scientific data depends on the purity of the reagents usedMonitoring is required to warrant reagent’s purityWater is the most commonly used reagent ; so far only the ionic contamination has been monitored through resistivitySome laboratory applications are TOC sensitiveInternational norms and standards require low TOC values for ultrapure water.

ÂÂ

Organic Breakthrough

0 15 30 45 60 75 90 105 120 1350

50

100

150

200

250

300

350

400

0 15 30 45 60 75 90 105 120 135

TOCRES

Time(min)

TOC (ppb) / Resistivity x 10 (MΩ.cm)

Organic breakthrough occurred with no resistivity change

ÂÂ

Contaminant BreakthroughContaminant Breakthrough

Feed Water

CarbonCarbon

Mixed Bed Ion Exchange ResinMixed Bed Ion Exchange Resin

Organic ScavengerOrganic Scavenger

0.22 0.22 µµm Membranem Membrane

Order ofBreakthrough

Product Water

Inorganic Ions

Dissolved Organics

Particles

Microorganisms

Silica

CarbonCarbon

Â

Laboratory Water Standards

ÂÂ

Pure Water Types

Tap water, which is already an elaborated product, is the raw material for laboratory grade water productionPure water for laboratory applications is usually divided in 3 grades of increasing purity : Type 3, 2 and 1.

ÂÂ

Water Types & Applications

Type III : glassware rinsing,heating baths and autoclaves filling, feed to Type I Lab Water SystemType II : buffers, pH solutions and microbiological culture media preparation ,clinical analysers andweatherometers feed, preparation of reagents for chemical analysis or synthesisType I : HPLC mobile phase preparation; blanks and sample dilution in GC, HPLC ,AA , ICP-MS and other advanced analytical techniques ; preparation of buffers and culture media for mammalian cell culture, IVF, reagents for molecular biology...

ÂÂ

ASTM Specifications

Type 1 Type 2 Type 3

Resistivity (MΩ.cm)@ 25°C

> 18.0 > 1.0 > 4.0

TOC (ppb) < 100 < 50 < 200

Sodium (ppb) < 1 < 5 < 10

Chloride (ppb) < 1 < 5 < 10

Silica (ppb) < 3 < 3 < 50

Bacteria (cfu/ml) (*) < 10 < 100 < 10,000

Endotoxin (EU/ml)(*)

< 0.03 < 0.25 NA

(*) When control is required : types A,B,C

ÂÂ

ISO 3696

Type 1 Type 2 Type 3

Resistivity (MΩ. cm)@ 25°C

> 10.0 > 1.0 > 0.25

TOC (ppb) NA < 80 < 400

Absorbance (254nm) 1 cm path (AU)

< 0.001 < 0.01 NS

Silica (mg/L) < 0.01 < 0.02 < 1.0

Dry Residue (mg/kg)after evaporation at110°C

NA < 1.0 < 2.0

ÂÂ

CAP & NCCLS Specifications

PARAMETER Type 1 Type 2

Resistivity (MΩ.cm) @25°C

> 10.0 > 1.0

Organics Activated Carbon (1) NS

Silicate (mg/L SiO2) < 0.05 < 0.1

Particulate 0.22 µm MembraneFilter

NS

Bacteria (cfu/ml) < 10 < 1,000

N.S. = Not specified (1) Not required by CAPSources: “Preparation and Testing of Reagent Water in the Clinical Laboratory,”

Second Edition, NCCLS Document C3-A2, Vol. 11, No. 13, August 1991.“Reagent Water Specifications,” College of American Pathologists, 1985.

ÂÂ

USP & EP Specifications

Summaryspecifications

USPPurified Water

EPPurified Water

EPHighly Purified Water

Source water Drinkable water according to EPA, EU,…Conductivity < 1.3 µS/cm @ 25 °C* < 4.3 µS/cm @ 20 °C < 1.1 µS/cm @ 20 °CTOC 500 ppb** 500 ppb** 500 ppb**Bacteria FDA specifications:

Action limit < 100 cfu/ml< 100 cfu/ml < 10 cfu/ 100 ml

Pyrogens (EU/ml) NA NAFor dialysis < 0.25

< 0.25

ÂÂ

USP 26 - Purified Water

Conductivity < 1.0 µS/cm from 10 to 15°C< 1.1 µS/cm from 15 to 20°C< 1.3 µS/cm from 20 to 25°C< 1.4 µS/cm from 25 to 30°C

TOC < 500 ppbpH > 5.0 and pH < 7.0Bacteria < 100 cfu/ml

ÂÂ

Millipore Proposed Specifications

Contaminant Parameter & unit Type 3 Type 2 Type 1

Ions Resistivity(MΩ.cm)

> 0.05 > 1.0 > 18.0

Organics TOC (ppb)Pyrogens (Eu/ml)

< 200NA

< 50< 0.25

< 10< 0.03

Particulates Particulates > 0.2µm (units / ml)

NA NA < 1

Colloids Silica (ppb) < 1000 < 100 < 10

Bacteria Bacteria (cfu/ml) < 1000 < 100 < 1

Â

Total Pure Water Solutions

ÂÂ

Makeup Water Purification System

ÂÂ

Makeup Water Purification System

ÂÂ

ÂÂ

ÂÂ

ÂÂ

ÂÂ

ÂÂ

ÂÂ

ÂÂ

ÂÂ

ÂÂ

Total Pure Water Solution

ÂÂ

Questions ?