Zuivering. Gertjan Medema Cursus drinkwatermicrobiologie 2012

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1 Zuivering Gertjan Medema Cursus drinkwatermicrobiologie 2012

2 Elimination in water treatment Two principal processes: Inactivation - Natural (biological) - Forced: disinfection (chemical, physical) Removal - Sieving (ultra/nanofilters) - Attachment (sand filters, soil, ceramic filters) - Flocculation + floc removal 2

(chemical, physical) Removal - Sieving (ultra/nanofilters) -

3 Virus structure Virus genome (RNA, ss/ds DNA) Capsid protein Spike 3

4 Inactivation 4

5 Virus inactivation in the environment Physical Heat or thermal effects Desiccation or drying Aggregation Adsorption to particles or surfaces Encapsulation or embedding Increasing inactivation at higher temperature; pasteurize Increased inactivation at lower moisture content or relative humidity; effects of RH differ between enveloped and non-enveloped viruses Clumping protects viruses from inactivating agents Adsorption protect viruses from inactivating agents; some specific chemical surfaces (heavy metals) are virucidal Viruses within membranes or larger particles are protected from inactivation Chemical Hydrogen ions; ph Viruses survive best near neutral ph and worst at ph extremes Organic matter Many viruses are stabilized and protected by dissolved, colloidal and solid organic matter, including fecal organics and natural organic matter (humic materials) Ammonia NH 3 has virucidal activity; manifest at higher ph (>ph 8) Salts and Ionic Strength Increased concentrations of salts are antiviral; some viruses are destabilized and inactivated by water lacking stabilizing salts (such as NaCl) ions such as Mg++ Enzymes Proteases and nucleases contribute to virus inactivation Biological Microbial activity Proteolytic activity Microbial predation Biofilms Biological treatment and microbial activity/metabolism in soils, sediments, water; several contributing mechanisms Proteolytic enzymes inactivate/denature virion proteins Engulfment, ingestion, etc. by protozoa, helminths, etc. Virus adsorption to biofilms can be protective or microbial activity in biofilms can cause virus inactivation and degradation 5

inactivating agents Adsorption protect viruses from inactivating agents; some specific chemical surfaces (heavy metals) are virucidal Viruses within membranes or larger particles are protected from

6 Principles of ozone process Ozone = strong oxidator Disruption of cell wall and reaction with nucleotides/enzymes: no reproduction At room temperature: ozone in gas Dosage of gas bubbles with diffusor Disinfection: contact time T of micro-organisms with ozone concentration C CT is design parameter (mg*l -1 min -1 ) 6

in gas Dosage of gas bubbles with diffusor Disinfection: contact time T of

7 Ozone process in practice In Concrete construction C out Contact time T Ozone gas C in Inactivation versus CT 7

8 Inactivation kinetics: quantifying Decimal Elimination Capacity Inactivation (log) Chick-Watson: N T k* C * T N e 10 log( N T n ) k * C T N * CT mg*l -1 *min -1 8

9 Inactivation kinetics: variability Inactivation (log) Shoulder model: delayed inactivation Non-linear model: influence of conditions (microbial and technological aspects) CT mg*l -1 *min -1 9

5-3 Non-linear model: influence of conditions (microbial

10 Inactivation of viruses, bacteria, bacterial spores and protozoan oocysts Inactivation (log) Oocysts of Cryptosporidium parvum Spores of Clostridium perfingens Viruses, Bacteria Environmental spores surrogate full-scale performance? CT ((mg ozone /l)*min) 10

5 0 Oocysts of Cryptosporidium parvum Spores of Clostridium perfingens -0.

11 k-value of some micro-organisms k-value (log10 inactivation rate constant) E.coli Viruses USEPA 1991 Giardia USEPA 1991 Spores of Clostridium perfringens Oocysts of Cryptosporidium Temperature 11

12 E. coli concentration (CFP/l) Lab is not practice: ozone example Ozonation CT 2 mg.min/l Expected E. coli inactivation: >>5 logs Full scale E. coli data: 1000 E. coli present in 4% of samples after ozone Removal 2.7 log Ozone in Ozone out 0.01 Dec-02 Mar-03 Jun-03 Oct-03 Jan-04 Apr-04 Aug-04 Nov-04 12

coli data: 1000 E. coli present in 4% of samples after ozone Removal 2.

13 Oxidation HOCl, O 3, OH et al Inactivation Concentration Time Temperature ph Organic compounds Inorganic compounds Virus type Virus protection 13

14 UV UV UV intensity Time Reactor Lamp type UV absorption Virus type Virus protection 14

15 Principles UV disinfection 15

16 UV sensitivity organisms: determined under well-defined batch conditions Collimated beam apparatus Inactivation Inactivation kinetics First order process inactivation rate constant k Tailing Shoulder UV-dose (mj/cm 2 ) 10 log( N t ) k * N Fluence 16

kinetics First order process inactivation rate constant k

17 Inactivation (log) UV sensitivity of viruses: examples 8 7 Poliovirus 7 studies 8 7 Adenovirus 5 studies, type 2,15,40, UV-fluence (mj/cm 2 ) 2 UV-fluence (mj/cm) 17

2,15,40,41 6 6 5 5 4 4 3 3 2 2 1 1 0 0 50 100 150 200 0 0

18 Log inactivation UV sensitivity of viruses (in collimated beam experiments) UV dose (mj/cm2) Poliovirus 1 (ssrna) Rotavirus SA11 (ssdna) Hepatitis A (ssrna) Coxsackie B5 (ssrna) Calicivirus bovine (ssrna) Adenovirus 40 (dsdna) 18

(mj/cm2) Poliovirus 1 (ssrna) Rotavirus SA11 (ssdna) Hepatitis A

19 K-values of pathogenic micro-organisms Campylobacter jejuni Vibrio cholerae Shigella dysenteriae Yersinia enterolitica Campylobacter jejuni E. coli O157 Salmonella typhi Legionella pneumophila Giardia muris Cryptosporidium parvum Hepatitis A Calicivirus Poliovirus Coxsackie virus Rotavirus Adenovirus k-value (cm 2 /mj) Bacteria Susceptible Protozoa, viruses Less susceptible

coli O157 Salmonella typhi Legionella pneumophila Giardia muris Cryptosporidium parvum Hepatitis A

20 Validation No legal requirement for validation of UV (or other) treatment systems in municipal water supply Water utility determines need for and strictness of validation Review by Inspectorate 20

water supply Water utility determines need for

21 Example 1: UV/H 2 O 2 PWN UV/H 2 O 2 system for disinfection and oxidation of micropollutants / NOM Fluence for oxidation 560 mj/cm 2 Fluence required for disinfection 120 mj/cm 2 System design: even at extremely low UVT (80%, 1 cm) and maximum flow at end of lamp life (80%) >120 mj/cm 2 Photo: PWN 21

22 Example 1: UV/H 2 O 2 Validation of disinfection PWN Experiments to determine inactivation of: Cryptosporidium (CB and pilot scale, collaboration of PWN, University of Alberta): > 4.8 log inactivation at 120 mj/cm 2 Giardia (CB, collaboration of PWN, University of Alberta) > 3.4 log inactivation at 120 mj/cm 2 Campylobacter (CB, see previous): >> 7.6 log inactivation at 120 mj/cm 2 Photo: PWN MS2 (CB, pilot scale, PWN): 4.2 log at 120 mj/cm 2 22

23 REF (mj/cm 2 ) Example 1: UV/H 2 O 2 Validation of reactor and fluence PWN Biodosimetry data of 2 10L30 systems in series show very good results REF avg = * dosimeter dose L30 reactors in series are expected to give superior performance REF 95CL = 0.982* dosimeter dose Dosimeter fluence (mj/cm 2 ) Data: Evides, PWN, Trojan, KWR 23

24 Example 2: UV as primary disinfection New reactor system Required fluence: 70 mj/cm 2 Biodosimetry at full scale Test unit constructed at water utility Local test water (with/without UVT reducer) 24

25 Bioassay setup Challenge vessel By-pass pump Dosing pump microbes Dosing pump coffee By-pass of feed water Vd Veer, Evides 25

26 REF (mj/cm 2 ) REF (mj/cm 2 ) Example 2: UV as primary disinfection REF mean = * dosimeter REF 95%CL = * dosimeter UVT 88 UVT 82 UVT Ca lcula 30te d flue 40nce, sce 50 na rio 60 2 (mj/cm 70 2 ) Dosimeter fluence (mj/cm 2 ) Medema & Beerendonk, 2005, in collaboration with Kruithof, van der Veer, Martijn, Dekker, Nugteren, Lem, van Loon (Evides, PWN, Trojan, Aqualab) Small scatter, slope > 1 and intercept > 0; 95%CL = ideal line: safe dosing without overdosing 26

27 REF (mj/cm 2 ) On-line monitoring of UV system performance Components Trojan UVT monitor Picture: Trojan UV CFD based UV fluence model REFmean = * dosimeter Flow meter UV sensor 30 REF95%CL = * dosimeter Dosimeter fluence (mj/cm 2 ) Biodosimetry to calibrate UV fluence model 27

28 Use of biodosimetry in process control in practice: the heart of the Water Safety Plan Inputs from online readings: Flow UVT UV intensity Microprocessor / PLC Calculate Reduction Equivalent Fluence 35 msec PLC Control lamp power Photo: P. Oostdam, Evides 28

29 Ultra/nanofiltration Virus elimination Removal: sieving 27 nm 29

30 Virus elimination filters Removal: attachment Electrostatic interactions Hydrophobic interactions - Virus characteristics pi capsid composition capsid structure - Particle composition composition electric charge structure - Matrix composition organic matter bivalent cations conductivity 30

31 Virus elimination Removal: flocculation Ca Ca Electrostatic interactions Hydrophobic interactions - Virus characteristics pi capsid composition capsid structure - Particle composition composition electric charge structure - Matrix composition organic matter bivalent cations conductivity 31

32 Coagulatie + snelfiltratie 32

33 Proefopstelling AKF locatie Berenplaat water na coagulatie/dlf Kool: Chemviron F400 Geen spoeling Filtratiesnelheid: 5 m/uur Contacttijd: 12 minuten 33

34 Concentratie (PFU.l Verwijdering van MS2 bacteriofagen -1 ) Verse AK in Verse AK uit Beladen AK in Beladen AK uit Dosering , Tijd (uren) 34

35 Concentratie (CFU/l) Verwijdering van E. coli en Clostridium-sporen E. coli SSRC Verse AK in Verse AK uit Beladen AK in Beladen AK uit , , Tijd (uren) 35

36 Concentratie (CFU/l) Verwijdering van Giardia en Cryptosporidium Cryptosporidium Giardia ,1 0,1 0,01 0,01 0, , Tijd (uren) Verse AK in Verse AK uit Beladen AK in Beladen AK uit 36

37 Verwijdering van micro-organismen DEC of logverwijdering van: Verse kool Beladen kool kolom 1 kolom 2 kolom 1 kolom 2 MS2 0,0 0,0 0,0 0,0 E. coli 0,0 0,1 0,3 0,3 Clostridium 0,4 0,6 0,4 0,4 Cryptosporidium 2,7 2,7 1,3 1,1 Giardia 2,1 2,0 2,1 2,2 37

38 Verwijdering natuurlijke indicatorbacteriën - onderzoek met grote volumes Lage concentraties indicatorbateriën in influent en effluent van het koolfilter Onderzochte volumes: liter Concentraties bepalen met: - Hemoflow (cross flow ultrafiltratie) 38

39 Verwijdering gedoseerde vs. natuurlijke organismen DEC of logverwijdering van: Verse kool Beladen kool kolom 1 kolom 2 kolom 1 kolom 2 E. coli gedoseerd 0,0 0,1 0,3 0,3 E. coli natuurlijk 0,4 0,4 1,1 1,0 Sporen gedoseerd 0,4 0,6 0,4 0,4 Sporen natuurlijk 1,1 1,0 0,9 0,9 Hypothese: pre-coagulatie bevordert de verwijdering door betere hechting 39

40 Micro-organism elimination in water treatment NL Inactivation Ozone UV UV/peroxide Chlorine dioxide Chlorine (safety) Removal Soil passage Membrane filtration (UF/NF) Sand filtration Flocculation/floc removal/filtration Reservoirs 40

Basics of UV Disinfection

Local Section Seminar Basics of UV Disinfection April 17, 2014 Joseph Moore, P.E. DuBois-Cooper Associates, Inc. 1 Presentation Outline Basics of Ultraviolet (UV) Disinfection Components of UV Disinfection