harmaan ja mustan veden käsittelyvaihtoehdot 28.4.2005 juha 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.

Harmaan ja mustan veden käsittelyvaihtoehdotHarmaan ja mustan veden käsittelyvaihtoehdot28.4.200528.4.2005

Juha Kiukas, Evac OyJuha Kiukas, Evac Oy

Onboard Wastewater TreatmentOnboard Wastewater Treatment

Waste water effects on receiving waters:Carbon is degraded causing loss of oxygenNutrients (N,P) cause eutroficationPathogens, bacteria, viruses and intestina

parasites => Public health problem

RegulationsRegulationsMARPOL 73/78

IMO Res. MEPC.2(VI)

USCG 33 CFR 159 TYPE II MSD

Alaska Title XIV

Biological Oxyg. Demand mg/l

50 0 30

pH No demand No demand 6 - 9

Total Suspended Solids mg/ml

100 (onboard test)

150 30

Faecal coliforms cfu/100ml

250 200 20

Free chlorine No demand No demand BDL

Future of marine wastewater treatmentFuture 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

Terminology:Terminology:TSS Total suspended solids

BOD5 Biochemical 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

nitratein nitrification of aerobic process

Nature of contaminants in wastewater:Nature of contaminants in wastewater:

Soluble organic compounds<0.1 um

Colloidal particles0.1-1um

Supracolloidal particles1-100um

BOD5

Some of the colloidal COD

A small part of settleable

Settleable particles>100um

Organics as COD in wastewaters+inorganics

Soluble BOD5

=> Greater proportion of soluble organics are included into BOD5

Stages of wastewater treatmentStages of wastewater treatment

Collecting & equalizing

Pretreatment Oxidation Separation Disinfection

Special requirements for shipboard Special requirements for shipboard wastewater treatmentwastewater 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 !!

Onboard wastewater:Onboard wastewater:Water: Vacuum

Black

Galley Pulper Accomm.

Grey

Laundry Swimming pool

Concentrations:

High

3.0 gBOD5/l

1.5 gTSS/l

High

2.0 gBOD5/l

2.5 gTSS/l

Extrem.high

10 gBOD5/l

10 gTSS/l

Dilute

0.2 gBOD5/l

0.1 gTSS/l

Dilute

0.3 gBOD5/l

0.3 gTSS/l

Dilute

0.3 gBOD5/l

0.1 gTSS/l

Volume:(for 3500 pax.)

Low

53 m3/day

Medium

175 m3/day

Very low

11 m3/day

Very high

595 m3/day

Medium

158 m3/day

Very high / short flux

105 m3/2 days/month

Faecal coliforms:

Extremely high

Lower Lower Lower Lower Lower

High strength DiluteFaecal contamination Free of faecal contamination

Dividing streams may benefit water treatment process

Characteristics of Wastewaters:Characteristics of Wastewaters:Divided streams for 3500 pax ShipDivided streams for 3500 pax Ship

Parameter: Unit:High strength (BW,GaW,FWw)

Low strength

(Acc. GW, LaW)

Flow m3/d 250 750

BOD mg/l 2500 220

TSS mg/l 2600 140

N mg/l 170 17

P mg/l 6 6

=> 75 % of Flow from the low strength streams=> 92 % of BOD5 from the high strength streams=> 95 % of TSS from the high strength streams

Design of the wastewater treatment process: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

Design of a wastewater Design of a wastewater treatment process: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

Conventional or advanced ?Conventional or advanced ?

Shipboardwastewater

treatment

Holding tanks”Physical chemical”

treatmentConventional

Biological treatmentAdvanced waste-water treatment

BW(+GW), smallDilution as solutionChlorine oxydation

95% sure

Space and weightEnvironmental aspect

Limited sailing100% sure solution

BW onlyGravity separation

Results varyCheap

BW + GWClean effluent

High rate processMore expensive

PretreatmentPretreatment

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

Pretreatment:Pretreatment: Relationship between size of

removed particles and BOD5/COD-removal

Proportion of particles < 100 μm could be up to 60 % of TSS

100

90

80

70

60

50

40

30

20

10

2.4

2.2

2.0

1.0

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

Diff

eren

tial V

olum

e (%

)

Particle Diameter (μm)

0.4 1 2 4 6 10 20 40 60 100 200 400 1000 2000

Cum

ulat

ive

Vol

ume

(%)

Source EVAC 14.6.2004 Finnclipper

Biological Wastewater Treatment:Biological Wastewater Treatment:

Solids enmeshment by flocculating microbes

Raw wastewater

Removal of BODby oxidation

Clean effluent

CO2

Sludge

Why AOP cannot be directly usedWhy 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.

Species Oxidation potential V

Fluorine 3.03

Hydroxyl radical 2.80

Atomic oxygen 2.42

Ozone 2.07

Hydrogen peroxide 1.78

Perhydroxyl radical 1.80

Permanganate 1.68

Hypobromous acis 1.59

Chlorine dioxide 1.57

Hypochlorous acid 1.49

Chlorine 1.36

Different biological processesDifferent biological processes Activated sludge

process

Membrane bioreactorprocess (MBR)

Suspended carrier biofilmprocess (SCBP)

Immobilised filter biofilmprocess (e.g. ICB)

Fluidized bio film process

(ASP) (FBR)

Supplier example:

Conventional - many suppliers

Zenon, Hamworthy, Evac, Rochem

Scanship, Hydroxyl Honeywell Degremont

Process description:

Suspended growth & biomass recirculation through sedimentation

Suspended growth & biomassrecirculation through membrane separation

Biofilm growth on suspendedcarrier media

Biofilm growth on immobilisedcarrier media

Biofilm growth on fluidizidedmineral carrier media

Design parameter:-loading rate (kgBOD/m3/d)

1.2 - 1.5

2.0 - 8.0

4.0 - 6.0

2.0 - 4.0

4.0 - 6.0

Separation 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.

Post treatment - DisinfectionPost treatment - DisinfectionHygienisation by UV – Needed if effluent do not comply the limits for pathogens

0.0000010.000010.00010.0010.010.1

110

1001000

0 1 2 3 4 5Time in Years

Faec. Col.

106/100 ml

Raw feed Permeate

Effluent samples from MBR with Kubota membranes:

Keypoints: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

Freedom-luokan alusFreedom-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.


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.


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.


Suodatus

UV-käsittely

Liete käsiteltäväksi

Sekoitustankki

Pesulavedet

Mustavesi

Vesi lieteen käsittelystä

Käyttövedet

Keitiövedet

Esikäsittelymoduli

Biologinen käsittely

Vaahdotuslinjat

Advanced technologiesAdvanced technologies

Dual stream

Electro-coagulation + DAF+Radicals

MEP

Membrane + Electro-coagulation

Evac

Membrane + RO

Rochem

External membrane

Hamworthy, Triqua, Rhodia

Submerged membrane

Evac, Zenon, Triqua, Wahag

Single stream

MBBR + DAF

Hydroxyl, Scanship

Two water streams ?Two water streams ?

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

Advantages Drawbacks

Divided streams on MBRDivided streams on MBR

Single stream Divided stream

MBR size 100% 75%

Membrane surface area

100% 25%

Investment cost (MBR)

100% 50%

MBBR + FlotationMBBR + Flotation

Black Galley Food Accom. Laundry Pool

Equalizing & mixing

Screen

MBBR

Coagulant & Flocculant chemicals

DAF Polishing filter

UV

OverboardSludge Sludge

MBR ( Membrane bioreactor )MBR ( Membrane bioreactor )


Equalizing & mixing

Screens

MBRUV

Overboard

SludgeSludge

Why MBR?Why MBR?

Effluent quality: Practically no solids => Crystal clear effluent BOD5 in effluent below 5 mg/l

Low pathogens in effluent without disinfection

Membrane variants comparisonMembrane variants comparison

Submerged plates

Submerged hollowfibre

External pressurized

Flux + + ++

Energy ++ + --

Glogging + - +

Proven ++ + +

Sludge levels

++ - +

All membranes have a limited lifetimeAll membranes have a limited lifetime

Time

Pressure Permeate flow

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

Bar

, m

3/h

)

MEP -MarisanMEP -Marisan

Equalizing

Screen

Coagulant & Flocculant

DAF

Bromine & Clorine gen.

Contact tank

Evac dual stream processEvac dual stream process


UV

Electro- coagulation

Lamella clarifyer

Dual screen

MBR UV

Overboard

Process comparison > 2000 paxProcess comparison > 2000 pax

Process description

MBBR + flotation

MBR

submergedMBR

external

Electrocoag. + AOP

MBR + electrocoag

.Split

streams

Foot print ++ + + ++ ++

Weight ++ + + ++ ++

Investment cost ++ + - - ++

Yearly operational costs without membrane replacement -- ++ + - +

Lifecycle cost - + -- -- ++

Sludge production & dewatering qualities + - - ++ ++

Effluent quality - ++ ++ -- +

Easiness of operation -- + ++ -- -

Process comparison < 1000 paxProcess comparison < 1000 pax

Process description

MBBR + flotation

MBR

submergedMBR

external

Electrocoag. + AOP

MBR + electrocoag

.Split streams

Foot print -- ++ + -- --

Weight -- ++ + -- --

Investment cost -- ++ + -- --

Yearly operational costs without membrane replacement -- ++ + -- --

Lifecycle cost - ++ -- -- --

Sludge production & dewatering qualities Not relevant Not relevant

Not relevant Not relevant Not relevant

Effluent quality - ++ ++ -- +

Easiness of operation -- ++ ++ -- --

Sludge handlingSludge handling Sludge from treatment process: Dry solids 2-3% Sludge after decanter centrifuging 17-27%

90% reduction of water

Sludge handlingSludge handling

After decanter centrifuging Holding Incinerator Steam dryer Filterpress or alternative sludge conditioning process

harmaan ja mustan veden käsittelyvaihtoehdot 28.4.2005 juha kiukas, evac oy

Documents

raw wastewater

wastewater treatment

high strength bw

high strength streamsparameter

low strength streams

onboard waste water

consumption of oxygen

organic matter