Harmaan ja mustan veden käsittelyvaihtoehdot 28.4.2005 Juha Kiukas, Evac Oy

1. Harmaan ja mustan veden käsittelyvaihtoehdot28.4.2005Juha Kiukas, Evac Oy Onboard waste water treatment is Separation and destruction of organic andinorganic contaminants in the wastewater to comply with the legislation or other quality demands.

2. Onboard Wastewater Treatment Waste water effects on receiving waters: • Carbon is degraded causing loss of oxygen • Nutrients (N,P) cause eutrofication • Pathogens, bacteria, viruses and intestina parasites => Public health problem

3. Regulations

4. Future of marine wastewater treatment • Limits will become closer to the land-based => May contain also limits for e.g. nutrients (N,P) • Technology: • Robust • Stand-alone plant with advanced technology • Continuous effluent monitoring with recirculation back to front-end if not complying the limits

5. Terminology: TSS Total suspended solids BOD5Biochemical Oxygen Demand, Amount of organic matter as consumption of oxygen by respiration within 5 days FC Faecal Coliforms as an indicator of intestial pathogens COD Chemical Oxygen Demand, Ultimate amount of organic matter as consumption of oxygen by chemicals SBOD5 & SCOD Soluble BOD5&COD, analysed after filtration NH4-N Ammoniacal nitrogen, that normally contributes most of soluble nitrogen in raw wastewater and is oxidised to nitrate in nitrification of aerobic process

6. Nature of contaminants in wastewater: => Greater proportion of soluble organics are included into BOD5 Organics as COD in wastewaters+inorganics Soluble organic compounds<0.1 um BOD5 Soluble BOD5 Colloidal particles0.1-1um Some of the colloidal COD Supracolloidal particles1-100um A small part of settleable Settleable particles>100um

7. Stages of wastewater treatment Disinfection Separation Pretreatment Oxidation Collecting & equalizing

8. Special requirements for shipboard wastewater treatment • Ship technical limitations ( space, weight, movements, heat etc. ) • Waste water concentrations & peaks • Short retention times ( collection & treatment) • Availability of chemicals and other consumables • Lack of process technical personnell • Reliability and redundancy requirements • Sludge handling • Odor control !!

9. Onboard wastewater: High strength  Dilute Faecal contamination  Free of faecal contamination Dividing streams may benefit water treatment process

10. Characteristics of Wastewaters:Divided streams for 3500 pax Ship => 75 % of Flow from the low strength streams => 92 % of BOD5 from the high strength streams => 95 % of TSS from the high strength streams

11. Design of the wastewater treatment process: Knowledge of influent / effluent parameters: • Flow parameters and patterns => Peak flow control! • Variation of concetrations => Organic peak flow control! • Process risks, e.g. toxic substances • Effluent limits Hydraulic design of the process: • One or two streams. Equalizing/holding/redundancy requirement • Hydraulic Retention Time (HRT) of the process • Design flux for membranes/DAF/UV etc. various process steps

12. Design of a wastewater treatment process: Organic design of the process: • Prefiltration rate • Mixed Liquor Suspended Solids (MLSS), Sludge Loading Rate (F/M), Sludge age (SRT) etc. various sizing parameters according selected process Sludge process • Holding, dewatering, drying and/or incinerating

13. Conventional or advanced ?

14. Pretreatment • Reduced loading by removal of solids • => Smaller bioreactor • => Less sludge production • Prevention of process failures: Cause of failure: Risk: Solution: • Hard objects Sludge treatment Catcher unit • Fat, oil & grease Membrane fouling Grease separator • Hair & lint Clogging of membranes Screen, Macerator

15. Pretreatment: Source EVAC 14.6.2004 Finnclipper 100 90 80 70 60 50 40 30 20 10 • Relationship between size of removed particles and BOD5/COD-removal • Proportion of particles < 100 μm could be up to 60 % of TSS 2.4 2.2 2.0 1.0 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 Cumulative Volume (%) Differential Volume (%) Particle Diameter (μm) 0.4 1 2 4 6 10 20 40 60 100 200 400 1000 2000

16. Biological Wastewater Treatment: CO2 Solids enmeshment by flocculating microbes Raw wastewater Clean effluent Removal of BOD by oxidation Sludge

17. Why AOP cannot be directly used Example 3500 pax ship If 35 % BOD is removed by ozone, the consumption is 597 kg/d. 2.86 MW electric power is required to produce ozone.

18. Different biological processes

19. Separation • Settling - biomass & solids are separated by gravity. Lamellas or ”carrier materials” can be used to increase settling efficiency. • Membrane - a fine filter is separating biomass & solids. Ultra- and microfiltration membranes are used for wastewater. • DAF (dissolved air flotation) - air is dissolved to water under pressure. When pressure drops, air creates microbubbles lifting biomass & solids to surface. • Filtration – for example sandfiltration is used to polish solid residues from the processed water stream. Filtration cannot be directly utilized for separation.

20. Post treatment - Disinfection Effluent samples from MBR with Kubota membranes: Hygienisation by UV – Needed if effluent do not comply the limits for pathogens

21. Keypoints: • Waste water treatment limits may change in the future on sensitive areas – Baltic sea is one of these areas ! • Process risk management with proper process design, flow control & understading of loading parameters • Pretreatment safeguards the process from risks • Many process options with same principal bioprocess

22. Freedom-luokan alus Mustalle veden 5 kokoamistankki, yhteensä 90 m3. Kolmessa on neljä ejektoria ja ejektoripumppua, kahdessa viisi. Putket AISI 316L. Harmaa vesi aina käsiteltävä. Biologinen preosessi – mikro-organismit käyttävät jäteveden ravintoa elintoiminnoissaan. Syövät myös ravintolsuolat, kuten typen ja fosforit. Aerobit bakteerit hajoittavat ravintoketjun tuottaen aktiivista jätettä, jossa korkea happipitoisuus. Jäte seisontatakin pohjalle ja takaisin esihapetusosaan. Kestää huonosti öljyä ja muita epäpuhtauksia. Kemiallisessa ensin esihapetus ja kemikaalien lisäys, jolloin orgaaniset ainesosat hajoavat. Kiinteä nousevat pintaa flokiksi, joka nousee pinnalle tai laskeutuu pohjaan sakkana, joka on helppo poistaa. Ongelmana on kemikaalien pääsy veteen. Page 22

23. Freedom-luokan alus Ultrasuodatuksessa kalvo, jonka huokoisuus mahdollistaa veden ja suolojen läpäiseminen 10 – 20 bar paineella. Käänteisosmoosissa korkeampi 20 – 70 bar paine. Kalvo ei ole huokoinen vaan ainoastaan puhdas vesi läpäisee sen. Kalvojen haavoittuvuus edellyttää harmaan veden esikäsittelyä. Esimerkiksi aurinkoöljy haittaa. Lämpötilan on oltava tarkasti oikea. Ultrasuodatus anteeksiantavampi ja vähemmän energiakulutus. RO kun tarvitaan korkea pouhdistustulos. Järjestelmän mitoituspohja 340 l / hlö /d. esikäsittelyssä lieteen saostuminen estetään suodattimilla Sekoitustankissa runkotankki 168 kuutiota, erillinen sekoitus Biologinen käsittely. biokalven hengittävä rakenne vähentää kolmanneksen elollisesti kuormasta. Tankkitilavuus 222 kuutiota. Kaksi bioreaktoria. Page 23

24. Freedom-luokan alus Sen jälkeen vaahvdotuslinjaan, joita kolme. Keskiallinen hyydyttäminen ja saostus. Painovoimaisesti vaahdotuslinjoihin, missä jätemassa erotellaan. 10 % vedestä kierrätetään. Paineen vapautuessa hyydyttyneeseen veteen syntyy mikrokupsia, joiden vaikutuksesta kiinteä partikkelit seinämille, jatkuvatoimiset raapimet. Viimiestelysuodattimiin pumppujen avulla. Jätevesi hitaaspyörivien rumpujen ympärille. Kiinteä jäte huuhdellaan vaipasta ja johdetaan keräilyrataan ja edelleen jatkoksäittelyyn UV_modulissa desinfiointi, jossa bakteerikanta tuhoutuu. Liete ennen UV-modulia kuivausjärjestelmän. Höytykuivain, suodatin poistoilmapuhallin ja höyrypatteri. Page 24

25. Freedom-luokan alus Pesulavedet Käyttövedet Mustavesi Keitiövedet Vesi lieteen käsittelystä Sekoitustankki Esikäsittelymoduli Biologinen käsittely Liete käsiteltäväksi Vaahdotuslinjat Suodatus Page 25 UV-käsittely

26. Advanced technologies

27. Smaller footprint Lower weight Lower consumables cost Better sludge dewatering qualities Improved recycle possibilities High strenght retrofit possibility with later upgrade of low strenght Two separate systems with own control Two feeding systems needed Lest cost efficienct for > 1000 persons More essential spare parts needed Two water streams ? Advantages Drawbacks

28. Divided streams on MBR

29. MBBR + Flotation Black Galley Food Accom. Laundry Pool Coagulant & Flocculant chemicals Polishing filter UV Screen DAF Equalizing & mixing MBBR Sludge Overboard Sludge

30. MBR ( Membrane bioreactor ) Black Galley Food Accom. Laundry Pool Screens Overboard Equalizing & mixing MBR UV Sludge Sludge

31. Why MBR? Effluent quality: • Practically no solids => Crystal clear effluent • BOD5 in effluent below 5 mg/l • Low pathogens in effluent without disinfection

32. Membrane variants comparison

33. All membranes have a limited lifetime 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 Bar, m3/h) Time Permeate flow Pressure

34. MEP -Marisan Bromine & Clorine gen. Contact tank Coagulant & Flocculant DAF Screen Equalizing

35. Evac dual stream process Black Galley Food Accom. Laundry Pool UV Dual screen Electro- coagulation Lamella clarifyer MBR Overboard UV

36. Process comparison > 2000 pax

37. Process comparison < 1000 pax

38. Sludge handling • Sludge from treatment process: Dry solids 2-3% • Sludge after decanter centrifuging 17-27% 90% reduction of water

39. Sludge handling • After decanter centrifuging • Holding • Incinerator • Steam dryer • Filterpress • or alternative sludge conditioning process