Optimising cooling seawater antifouling strategy through Pulse-Chlorination Henk Jenner, Maarten Bruijs & Harry Polman Goa, February 2008 Experience you can trust.
www.kema.com T H E W O R L D O F K E M A Experience you can trust.
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 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 3
Process & Cooling Water (PCW) How to protect the environment against the industry and the industry against the environment 4
Macrofouling: mitigation why more attention for macrofouling mitigation? Economical efficiency improvement optimal control longer periods between maintenance outages less labour in cleaning cost reduction biocide use Technical less clogging problems less tube leakages Ecological less environmental impact 5
Sequence: micro- and macrofouling Four phases in biofouling development biochemical conditioning of substrates colonisation by bacteria colonisation by single cell organisms colonisation by macro fouling organisms substrate is the limiting factor, not nutrition 6
Macrofouling in cooling water systems driving force for settlement and growth is water turbulence inside the cooling water conduits conditions inside the system are optimal due to: absence of light nutrition; ad libidum oxygen absence of predators 7
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Erosion corrosion (tube blocking) 13
Macro-fouling: settlement of spat 14
Australia: 1999 Cullen Bay (marina): Mytilopsis sallei (adamsi); eradicated in 9 days by 160 ton hypochlorite and 54 ton CuSO 4 killed all life!!; Costs $AU 2.3 million; 280 people involved Regular surveys are carried out in the international ports 15
Barnacles 16
Brackish water macrofouling Chalkworms: Ficopomatus enigmaticus Mytilopsis leucophaeata Hydroids: Cordylophora caspia 17
Drillers Martesia striata in ABS pipe line (Acrylonitrile Butadiene Styrene) 18
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Fresh water nuisance species Zebra mussel (Zeebs): Dreissena polymorpha & D. bugensis Asiatic clam: Corbicula fluminea C. fluminalis (exotics) 20
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) UV (only small size applications) Hydrogen peroxide Peracetic acid (experimental) 21
Chlorine (Na) hypochlorite (sea water) NaOCl + H 2 O ClO - + Na + ClO - + H 2 O HOCl + HO - HOCl + Br - HOBr + Cl - HOBr BrO - + H + 22
Chlorine (Na) hypochlorite (sea water) 23
Chlorine (Na) hypochlorite: demand HOCl / HOBr and biota = oxidising Substition reaction with organic material leading to CBPs: haloforms, halonitriles, haloaceticacids, halophenols HOCl (Br) + NH 3 NH 2 Cl (Br) + H 2 O HOCl (Br) + NH 2 Cl NHCl ( 2 Br 2 )+ H 2 O HOCl + NHCl 2 NCl 3 + H 2 O (swimming pools) 24
Background chlorination in seawater Worldwide the most applied method once-through CW-systems Still one of the best solutions Proven efficacy Relatively low costs Applied as continuous or intermittent low level chlorination Optimisation: reduction environmental impact and costs is possible! 25
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 years reduction chlorine dosing (discharge) improved cost benefit ECP maintenance (labour & acidification cleaning) Low(er) environmental impact 26
Pulse-Chlorination Best Available Technique (BAT): information from the European Commission (2000) integrated Pollution Prevention and Control (IPPC) BAT Reference Document (BREF) 27
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 of 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 28
General reaction patterns of bilvalves In- (ciliated) & exhalent siphons Start dosing Stop dosing No dosing period = method profit 29
MusselMonitor Biological Early Warning System 30
Oyster after regime 31
P-C bivalve behaviour % open 100 75 50 25 0 0:00 6:00 12:00 18:00 0:0 Control absolute opening 550 500 450 400 350 Regime 10 on / 10 off; 0,3 mg Cl 2 /L TRO 300 time 32
Bivalve behaviour during regime Blank regime regime regime change 10/10 TRO 0,5 900 700 500 1000 500 1000 500 0 900 700 500 33
Full scale test: manual measurements 1.75 1.50 inlet dosing point / condensor / outlet 1 3 2 4 1.25 (mg/l) 1.00 1 TRO/FO 0.75 2 3 4 0.50 1 0.25 2 3 4 0.00 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 INLET INLET HE HE OUTLET OUTLET 34
Monitoring macrofouling settlement KEMA Biofouling Monitor 35
Mobile Laboratory at Verve Energy 36
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 turbidity ph dissolved oxygen salinity temperature water flows 37
Mytilus edulis Control: white flesh Pulsed : 10 weeks, no flesh only skinny mantle tissue Control Pulsed 38
What it is all about! Return water box at E.ON PP Maasvlakte (NL) before Pulse-Chlorination after Pulse-Chlorination (fouling species mitigated: barnacles, mussels, oysters, hydroids) 39
After Pulse-Chlorination Return water box at Verve Energy (AUS) after Pulse-Chlorination (fouling species mitigated: barnacles, mussels) 40
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 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 41
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 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 42
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 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 43
Questions & Discussion 44
THE END 45
Control of macrofouling: Chemical Non-oxidising biocides Quaternary ammonium compounds (QAC) Mexel Copper & Cu-Ag (evident) Acoustics and sparking (experimental) Magnetic fields (experimental) Viruses (one virus spp effective against Zeebs) Surfactants; treatment periodic; rapid killing; slow degradation; clay addition outlet 46
Non-oxidising biocides QACs Clam Trol; GE Betz: alkyl dimethyl benzyl ammonium chloride + dodecylguanidine H-130; Calgon: didecyl dimehyl ammonium chloride (DDAC) Bulab 6002; Buckman: poly[oxyethylene(dimethylimino)ethylene(dimethyliminio)ethylene dichloride 47
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 Cl 2 /L TRO maximum limits Netherlands Limits are set by local water authorities, there are differences at each location. In general: sea water: ~0.2 mg Cl 2 /L TRO fresh water: ~0.1 mg Cl 2 /L FO 48
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 if there is reasonable doubt then more research is necessary short-term or acute toxic effects long-term toxicity at low levels 49