Optimising cooling seawater antifouling strategy through

Experience you can trust.

antifouling strategy through Pulse-Chlorination®

Henk Jenner, Maarten Bruijs & Harry Polman

Goa, February 2008

www.kema.com

Experience you can trust.

T H E W O R L D O F K E M A

Process & Cooling Water (PCW)

• Part of ‘KEMA Technical & Operational Services’ team• Consultancy, R&D and training• Expertise fields are:

– process water: demin installations– steam cycle

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– Low and high T corrosion, including MIC– biofouling control (micro + macro, Legionella) – Fish entrainment & impingement (deflecting)– environmental effects & EIA’s– 3D-modelling CW discharge T & chemicals (CBP’s)

• Clients: power industries & (petro-)chemical plants worldwide

“How to protect the environment against the industryand

Process & Cooling Water (PCW)

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andthe industry against the environment”

Macrofouling: mitigation

why more attention for macrofouling mitigation?Economical – efficiency improvement– optimal control– longer periods between maintenance outages

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– less labour in cleaning– cost reduction biocide useTechnical– less clogging problems– less tube leakagesEcological– less environmental impact

Sequence: micro- and macrofouling

Four phases in biofouling development

• biochemical conditioning of substrates• colonisation by bacteria• colonisation by single cell organisms

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• colonisation by macro fouling organisms

substrate is the limiting factor, not nutrition

Macrofouling in cooling water systems

driving force for settlement and growth is waterturbulence inside the cooling water conduits

conditions inside the system are optimal due to:

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• absence of light• nutrition; ad libidum• oxygen• absence of predators

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Erosion corrosion (tube blocking)

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Macro-fouling: settlement of spat

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•Australia: 1999 Cullen Bay(marina): Mytilopsis sallei(adamsi); eradicated in 9 days by 160 ton hypochlorite and 54 ton CuSO4 killed all life!!;

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ton CuSO4 killed all life!!; Costs $AU 2.3 million; 280 people involved•Regular surveys are carried out in the international ports

Barnacles

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Brackish water macrofoulingMytilopsis leucophaeata

Chalkworms: Ficopomatus enigmaticus

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Hydroids: Cordylophora caspia

“Drillers” Martesia striata in ABS pipe line (Acrylonitrile Butadiene Styrene)

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Fresh water nuisance species

• Zebra mussel (Zeebs): Dreissena polymorpha & D. bugensis

• ‘Asiatic’ clam: Corbicula flumineaC. fluminalis (exotics)

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Chemical control of macrofouling:

Oxidising Biocides (focus)• Chlorination Na-hypochlorite = bromine chemistry• Ozone: bromide oxidising →bromine chemistry +

hydroxyl radicals• Chlorine dioxide (small fresh water applications)

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• UV (only small size applications)• Hydrogen peroxide – Peracetic acid (experimental)

Chlorine (Na) hypochlorite (sea water)

NaOCl + H2O → ClO- + Na+

ClO- + H2O ↔ HOCl + HO-

HOCl + Br- ↔ HOBr + Cl-

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HOBr ↔ BrO- + H+

Chlorine (Na) hypochlorite (sea water)

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Chlorine (Na) hypochlorite: demand

• HOCl / HOBr and biota = oxidising• Substition reaction with organic material leading to

CBPs: haloforms, halonitriles, haloaceticacids, halophenols

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• HOCl (Br) + NH3 → NH2Cl (Br) + H2OHOCl (Br) + NH2Cl → NHCl2 (Br2) + H2OHOCl + NHCl2 → NCl3 + H2O (swimming pools)

Background chlorination in seawater

• Worldwide the most appliedmethod once-through CW-systems

• Still one of the bestsolutions

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• Proven efficacy• Relatively low costs• Applied as continuous or

intermittent low levelchlorinationOptimisation: reduction environmental

impact and costs is possible!

Alternative chlorination procedures

• The Dutch Power Industry contracted KEMA (1998) to investigate alternatives in chlorination procedures for reducing the amount of chlorine, without loss of effectiveness in fouling control

• Two year intervals for maintenance should be 4 to 6

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years• reduction chlorine dosing (discharge)• improved cost benefit ECP maintenance (labour &

acidification cleaning)• Low(er) environmental impact

Pulse-Chlorination®

Best Available Technique (BAT):• information from the European Commission (2000)• integrated Pollution Prevention and Control (IPPC)• BAT Reference Document (BREF)

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Pulse-Chlorination®

• Pulse-Chlorination® is based on short successive periods with and without chlorine at which the fouling organism behaviour is leading

• Forces a deterioration of the physiological condition

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p y gof the bivalves and barnacles; switching from aerobic to anaerobic metabolism and vice versa

• After exposure to a chlorination period, bivalves show a recovery period before full opening and restart filtration

General reaction patterns of bilvalvesIn- (ciliated) & exhalent siphons Start

dosing

Stop

dosing

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No dosing period

= method profit

MusselMonitor®

Biological Early Warning System

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Oyster after regime

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P-C bivalve behaviour

02550

75100

0:00 6:00 12:00 18:00 0:0

% o

pen

Control

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300

350

400

450

500

550

time

abso

lute

ope

ning

Regime

10”on / 10”off;

0,3 mg Cl2/L TRO

Bivalve behaviour during regime

500

700

900

Blank regime regime regime change 10/10 TRO 0,5

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500

1000

0

500

1000

500

700

900

1.00

1.25

1.50

1.75

(mg/

L)

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1

2 4

inlet dosing point / condensor / outlet

Full scale test: manual measurements

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0.00

0.25

0.50

0.75

9:00 9:14 9:28 9:43 9:57 10:12 10:26 10:40 10:55 11:09 11:24 11:38 11:52

time

TRO

/FO

INLET INLET HE HE OUTLET OUTLET

2

2

1

3

3

4

4

Monitoring macrofouling settlement

• KEMA Biofouling Monitor

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Mobile Laboratory at Verve Energy

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Mobile laboratory

• testing bivalve behaviour in a laboratory• side stream of the seawater cooling system• dedicated to the CW specifications• on-line measurements:

– FO/TRO

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– turbidity– pH– dissolved oxygen– salinity– temperature– water flows

Mytilus edulis

• Control: white flesh• ‘Pulsed’: 10 weeks, no flesh only skinny mantle

tissue

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Control “Pulsed”

What it is all about!Return water box at E.ON PP Maasvlakte (NL)

before Pulse-Chlorination after Pulse-Chlorination

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(fouling species mitigated: barnacles, mussels, oysters, hydroids)

Return water box at Verve Energy (AUS) after Pulse-Chlorination

After Pulse-Chlorination

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(fouling species mitigated: barnacles, mussels)

Pulse-Chlorination references

• E-ON PP Maasvlakte, Rotterdam (saving 150 kEur/yr) • Shell Chemical Netherlands, Moerdijk and Pernis R’dam• DOW Chemical Benelux, Terneuzen (saving 1,000 kEur/yr)• Reliant Energy Europe PP, Hemweg• Essent/EPZ PP, Borssele

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• ExxonMobil Rotterdam Europort, Rotterdam• AVR waste incinerator, Rotterdam (saving 30 kEur/yr)• GDA waste incinerator, Amsterdam • Yara Fertilizer Plant (Hydro Agri), Sluiskil• Wolsong NPP, South Korea (saving 800,000 USD)• Qatar Liquefied Gas Company ltd.• Verve Energy Kwinana PP, Western Australia

AQUATIC NUISANCE ORGANISMS IN BALLAST WATER

• IMO Marine environment committee GESAMP Report of the chemistry and (eco)toxicological consequences of chlorination in marine waters and its implication for in situ production and application on ships

IMO

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• This document contains the essential aspects and background concerning chemistry, (eco)toxicological aspects and recommendations for dosing and monitoring of hypochlorite for ballast water treatment

Conclusions

• Pulse-Chlorination is a major step forward in lowering use of Na-hypo by circa 50%, i.e. less CBPs

• bromoform is main component of CBPs, with half live of few days. Volatilisation is main route disapearance

• long term exposure of Sea Bass to low level

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chlorination has very limited effects• the often heard statement of dangerous “carcinogenic”

effects induced by chlorination is not confirmed by on site studies and therefore questionable

• chlorination as a tool for ballast water is still a real good and (to my opinion) the best solution up to now

Questions & Discussion

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THE END

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Control of macrofouling: Chemical

Non-oxidising biocides• Quaternary ammonium compounds (QAC)• Mexel• Copper & Cu-Ag (evident)• Acoustics and sparking (experimental)

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• Magnetic fields (experimental)• Viruses (one virus spp effective against Zeebs)• Surfactants; treatment periodic; rapid killing; slow

degradation; clay addition outlet

Non-oxidising biocides

QACs• Clam Trol; GE Betz: alkyl dimethyl benzyl

ammonium chloride + dodecylguanidine• H-130; Calgon: didecyl dimehyl ammonium chloride

(DDAC)

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• Bulab 6002; Buckman: – poly[oxyethylene(dimethylimino)ethylene(di-

methyliminio)ethylene dichloride

Total Residal Oxidant: limits

• TRO limits in Europe:– water authority pursues less chlorine discharge– limit determined by (local) regulator (based on BAT)– usually 0.2 – 0.5 mg Cl2/L TRO maximum limits

• Netherlands

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– Limits are set by local water authorities, there are differences at each location. In general:•sea water: ~0.2 mg Cl2/L TRO •fresh water: ~0.1 mg Cl2/L FO

Na-hypochlorite & environmental effects

• formation of a large number (>200) of CBP’s (<< µg/l) and measured concentrations are far below acute toxicity levels

• Dutch water authorities: precautionary principle

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if there is reasonable doubt then more research is necessary– short-term or acute toxic effects – long-term toxicity at low levels