A Green Future: Developpging Caribbean Water and Waste...

A Green Future:

Developing Caribbean Water and Waste Resources p g

Caribbean Water and Wastewater Association

C f d E h b2009 Conference and Exhibition

October 4-10, 2008St. Thomas, USVI

18th Annual CWWA Conference and Exhibition

Reducing power consumption, conserving resources, and reducing water price while upgrading and augmenting an existing

SWRO facility to meet increased water demand and plantSWRO facility to meet increased water demand and plant reliability in St. Maarten.

PROPRIETARY & CONFIDENTIAL

Shawn Meyer-Steele - William Sheehan

Introduction-In 2007several factors were contributing to water shortages including

tourism and population growth as well as operational deficiencies at the

Introduction

tourism and population growth as well as operational deficiencies at the existing desalination plant.

-An immediate increase in supply was required in order to meet the present demand and mitigate the potential for future shortages.present demand and mitigate the potential for future shortages.

-The Cay Bay desalination plant was contracted to produce 13,500 M3/D but the outdated and inefficient plant was averaging 10,600 M3/D.

Th ti f th ld l t i ifi tl hi h th-The power consumption of the old plant was significantly higher than what is possible by state of the art plants, and was wasting precious and expensive electricity.

In the midst of this prolonged water shortage Air Fin Holding St-In the midst of this prolonged water shortage, Air-Fin Holding St. Maarten N.V. (AFH), (a wholly owned subsidiary of SSW) won a tender to provide a new 3,000 M3/D potable water plant and take over operation of the existing Cay Bay SWRO Plant for the St. Maarten

PROPRIETARY & CONFIDENTIAL 2

p g y yGovernment.

Cay Bay Project OverviewCay Bay Project Overview

• Under the Build Own, Operate and Transfer agreement signed between the St. Maarten Government and Air Fin Holding St. Maarten/Seven Seas Water Corporation, AFH/SSW would upgrade, expand, maintain and operate the existing 3,600,000 US

ll d (USGPD) S t R O i (SWRO)gallons per day (USGPD) Seawater Reverse Osmosis (SWRO) Plant at Cay Bay as well as design and build a new plant at Cupecoy 1,000,000 USGPD SWRO Plant at Cupecoy.

• The water produced is supplied to the St. Maarten Power and Water Authority GEBE, who distributes it to their residential and commercial clients throughout St. Maarten. g

• This paper will address the practical and technical issues faced in the design and operation of an outdated plant being redesigned

d d d t b ffi i t ibl ith t i t ti i


and upgraded to be as efficient as possible without interruption in the water supply.

Cay Bay Plant HistoryCay Bay Plant History• The Cay Bay Plant; St. Maarten has been in existence and

operating by numerous entities since 1986.

• The original (contract) was constructed and operated by Aqua Design in 1986 under a ten (10) year BOOT agreement.

• In 1996 Enerserve N.V. (part of the Culligan group), was awarded a sixty (120) month (BOOT) agreement from the St. Maarten governmentg

• At that time a new plant was built, (using some of the existing infrastructure) with the production capacity increased to 2,150,000 US GPD (8 100 M3/d) ith fi (5) SWRO t i d t (2)US GPD (8,100 M3/d) with five (5) new SWRO trains and two (2) BWRO trains.

• In 1997 the BOOT agreement was expanded to include a sixth


In 1997 the BOOT agreement was expanded to include a sixth (6th) SWRO train and a third (3rd) BWRO train for an increased total production capacity of 2,587,000 USGPD (9,800 M3/D).

Cay Bay Plant HistoryCay Bay Plant History• In 1999 after US Filter purchased Enerserve/(Culligan), state of

the art technology at the time was implemented with the additionthe art technology at the time was implemented with the addition of Dupont B10 permeators.

• In 2001 Enerserve/US Filter were one of the first to install ERI PX ERD’s on a large scale plant at Cay Bay Plant in both a 2,520 M3/D and a 3,900 M3/D train, in cascade arrays.

C d i i d i t hi• Cascade arrays are an inexpensive design to achieve more potable water production from an existing plant but does not take advantage of the full energy savings that could be gained by utilizing isobaric energy recovery devices in a standard arrayutilizing isobaric energy recovery devices in a standard array design.


Cay Bay Plant HistoryCay Bay Plant History

• When AFH/SSW took over operation of the Plant in FebruaryWhen AFH/SSW took over operation of the Plant in February 2008 it was in extremely poor shape, very unreliable, inefficient, unsafe to operate and unable to supply contractual minimum / island water demand.

• Seven Seas immediately started work on the planned upgrades and improvements needed to ensure St. Maarten with a reliable source of potable water with a greatly improved efficiency andsource of potable water with a greatly improved efficiency and reliability.


Typical SWRO PlantTypical SWRO Plant

Chemical

Ultrafiltration (UF)

ProductReservoir

Feedwater Supply

Concentrate Discharge

Pretreatment RO Building

Storage

SRWO Unit


SWRO Plant: Feed Water SupplySWRO Plant: Feed Water Supply

• Feed water is collected from a seawater intake or beach wells

• From the intake, a feed pump will convey feed water to the pretreatment system


SWRO Plant: PretreatmentSWRO Plant: Pretreatment

• Multimedia filters, Bag Filters, etc

• 1st filtration step: straining interception impaction1st filtration step: straining, interception, impaction, sedimentation, flocculation, and absorption

• (UF may be used in highly turbid waters as alternative to filters to reduce lifecycle costs)


SWRO Plant: Sea Water Reverse Osmosis Unit

• Seawater Feed (wells or intake)

• Cartridge filtration

• Reverse osmosis (membranes, high pressure pump, piping)

• Energy recovery

• Concentrate Discharge

• Clean-in-place systemClean in place system


SWRO Plant: Post TreatmentSWRO Plant: Post Treatment

• Finish potable water

H b l dd h d• pH balance, add hardness

• Disinfection (Chlorine, UV, Ozone)( , , )

• Chemical addition systems


Partial List of Upgrades UndertakenPartial List of Upgrades Undertaken

• Among the long list of plant upgrades and system redesigns to achieve the plant efficiency, dependability, reliability, safe operation, and water demand that is the SSW hallmark are the following:

• Intake/ Pretreatment / Post treatment

• SWRO Unit Redesignsg

• BWRO, Partial 2nd Pass Units

• Safety / Electrical Upgrades• Safety / Electrical Upgrades


Partial List of Upgrades UndertakenPartial List of Upgrades UndertakenIntake/ Pretreatment / Post treatment

M j ti f i t k d t t t t d d t b d i d d• Major portion of intake and pretreatment system needed to be re-designed and replaced.

• As the plant had over its long history been increased in increments there were areas of hydraulic inefficiency where piping diameter had to be increasedareas of hydraulic inefficiency where piping diameter had to be increased, bottlenecks eliminated and materials upgraded.

• There was a 38 PSI pressure drop across the pretreatment stages when AFH/SSW took over the plant operationAFH/SSW took over the plant operation.

• Additional media filters & cartridge filter needed to be added to ensure proper design flows and proper velocities for adequate pretreatment, increased net positive suction head (NPSH), and greater flow. p ( ) g

• At one point in the system pretreatment there were two (2) 16” lines that fed to a single 16” tee, which returned to dual 16” lines. This was redesigned to two (2) separate 16” feeds.


• Four unused carbon post-treatment filters were converted to calcium carbonate filters and put in service for improved product water quality.


RO Unit Redesigns

• A host of changes and improvements were implemented throughout the Plant. The Plant can accommodate Seven SWRO units, of which Units 2,3,4,5, 6, and 7 were operating when AFH/SSW took possession of the plant. The bay for unit number 1 was empty.

• A completely new Unit was designed and installed to replace SWRO Unit Six. Units Three and Seven were upgraded with new controls and pgmore efficient energy recovery devices (ERI PX’s).

• SWRO Unit Five is scheduled for decommissioning after the redesigned Unit Seven comes on line later this year after all redesign and upgradesUnit Seven comes on line later this year after all redesign and upgrades are complete.

• Two new, three-stage, high recovery (95%) second pass units were installed to replace the older single stage (80%) recovery units


installed to replace the older single stage (80%) recovery units.


SAFETY / ELECTRICAL UPGRADES

• Numerous safety enhancements ran the gamut from as simple as improved grounding and lighting to more complicated projects like the isolation of the electrical control systemlike the isolation of the electrical control system.

• SSW built 2 electrical rooms around main switch gear where Motor Control Centers, control systems, and Variable Frequency Drive motor controls were built to safeguard delicate electrical equipment, prevent corrosion, improve efficiency through cooler operating temperatures. There is also the added safety benefit of

h i l ti b t th SWRO l t ( ith i da physical separation between the SWRO plant (with pressurized seawater) and the electrical controls.


SWRO TRAIN DETAILSSWRO TRAIN DETAILSArray Membranes Production HP Pump ERD

(M3/Day)SWRO 1 Old*1 - - - - -

New*1 - - - - -

SWRO 2 Old 3M/3M - - PD PeltonNew 3M/3M Toray-400 1,690 PD Pelton

SWRO 3 Old Pelton/PX Centrifugal Pelton/PXSWRO 3 Old Pelton/PX Cascade 3M/3M

- - Centrifugal Pelton/PX

New 3M/3M Toray-400 3,970 Centrifugal PXSWRO 4 Old 3M/3M - 1,690 P/D Pelton,

New 3M/3M Toray-400 1,690 P/D PeltonSWRO 5 Old Pelton/PX

Cascade3M/3M

- - P/D Pelton/PX

New*2 3M/3M Toray-400 1,440 P/D Pelton

SWRO 6 Old 3M/3M Dupont - PD TurboNew 6M Toray-400 3,970 PD PX

SWRO 7 Old 7M - - Centrifugal PeltonNew*3 7M Toray 400 3 970 Centrifugal PX


New*3 7M Toray-400 3,970 Centrifugal PX

SWRO TRAIN DETAILSSWRO TRAIN DETAILS

*(1) SWRO Unit 1 was an empty bay on takeover, and plans are for it to remain so into the foreseeable futureinto the foreseeable future.

*(2) SWRO Unit 5 will be decommissioned this year after the completion of renovations for SWRO Unit 7.

*(3) Later this year the SWRO Unit 7 retrofit will be complete including replacement(3) Later this year the SWRO Unit 7 retrofit will be complete, including replacement of the High Pressure pump with smaller pump and ERI PX’s,

*(4) VFD motor control, new electrical gear, membranes, controls, and manifolds provide a calculated reduction in the Unit # 7 electrical load from 850 to 400 Amps

* (5) All redesigned units with centrifugal high pressure pumps employ VFD control and positive displacement pumps with soft starters.


BWRO TRAIN DETAILSBWRO TRAIN DETAILS

Array Membranes Production Recovery

M3/Day

BWRO 3 Old 1 Stage Hollow fiber - 80%

New*1 1 Stage Hollow fiber 1,745 80%

BWRO 1 Old 1 stage Hollow Fiber - 81%

New 3 stage Spiral wound 2,100 95%

BWRO 2 Old 1 Stage Hollow Fiber - N/A

New 3 stage Spiral wound 2,100 95%

BWRO 4 Old 1 stage Spiral wound - 81

New*2 3stage Spiral wound 1,963 95%

*1 - BWRO Three is an existing hollow fiber unit operating at 80% recovery in a single stage which will be decommissioned for standby after completion of renovations.

*2 – BWRO Four is a single stage spiral wound unit that will be converted to a three stage design with an


2 BWRO Four is a single stage spiral wound unit that will be converted to a three stage design with an increase in recovery from 81 to 90%.

Average Production and Energy Consumption at Cay BayConsumption at Cay Bay

LEGEND


LEGEND------ Daily production m3/day----- Electrical consumption kWh/Day

CAY BAY PLANT DETAILSCAY BAY PLANT DETAILSCay Bay Plant Capacity:

•Contractual: 3,564,000 US Gallons per Day (13,500 M3/D) in Six Units

•Partial second pass in 4 units.

Product Quality:y

•Actual: <280 uS/cm

•Contract: <300 uS/cm

Power Consumption:

•On takeover: ~22 kWh / KIG (18.2 kWh/KUSG)

Act al at Present ~16 kWh / KIG (13 3 kWh/KUSG)•Actual at Present: ~16 kWh / KIG (13.3 kWh/KUSG)

•Completion of upgrades: Estimated ~14.0 kWh / KIG (11.7 kWh/KUSG)


CAY BAY ENERGY IMPROVEMENTCAY BAY ENERGY IMPROVEMENT

- Seven Seas Water is presently 80% complete with a multi-million dollar upgrade and efficiency improvement project. -Specific energy consumption has been reduced from over 18.3 kWh/KUSGal to an average 13.3 kWh/KUSGal at present.


p-When all upgrades are have been completed, final electricity consumption is expected to be 11.7 kWh/KUSGal, approaching the energy consumption of the newly constructed Seven Seas Cupecoy Plant.

bl l hl l i l iTable One: Cay Bay Plant monthly electrical consumption

2009 Cay Bay Monthly Electrical Consumption - kWh / KIG y y y p

1819202122

12131415161718

12

Jan (

Actual)

Feb (A

ctual)

Mar (A

ctual)

Apr (A

ctual)

May (A

ctual)

Jun (

Actual)

Sep (e

st.)

Oct (es

t)

The savings are calculated to be over 29,700 kWhr per day (or USD $1,300,000 per year in electricity costs assuming electrical costs of US$0.13/kWhr).

This is a reduction of over 120,000 tons of CO2 emissions per year (based on 2 pounds of carbon emissions per kilowatt hour generated by a average commercial diesel generator).


The reduced power consumption frees up previously dedicated energy generating equipment for other needed projects without requiring new installed capacity, and significantly reduces the carbon footprint of St. Maarten.

bl l hl l i l iTable Two: Cupecoy Plant monthly electrical consumption

2009 Cupecoy Monthly Electrical Consumption kWh / KIG2009 Cupecoy Monthly Electrical Consumption - kWh / KIG

19202122

1213141516171819

12

Jan (

Actual)

Feb (A

ctual)

Mar (Actu

al)

Apr (A

ctual)

May (A

ctual)

Jun (

Actual)

The recently commissioned Seven Seas Water SWRO Plant located at Cupecoy Yacht Club, Sint Maarten. Present electricity consumption is less than 14 kWh per 1000 imperial gallons produced = 11.7 kWh per 1000 US gallons.


gallons.

Cay Bay Plant: The Old and the New HP Manifold

OLD High Pressure Manifold Design NEW High Pressure Manifold Design

Seven Seas completed numerous improved manifold designs with lower pressure drops, improved performance and tili ti f t i l t t l t 20


utilization of materials meant to last 20 years.

Cay Bay Plant: HDPE Installation #1

This first set of piping redesign resulted in decrease in the pressure prop across the system and an increase in the feed pressure to the feed pumps of 5-7 psi


feed pressure to the feed pumps of 5 7 psi.

This resulted in an increase in the existing plant production capacity by ~800-1000 m3/day

Cay Bay Plant: HDPE Installation #2

The Second HDPE re design increased the feed pressure to SWRO units by another 2 psi


The Second HDPE re-design increased the feed pressure to SWRO units by another 2 psi.

Cay Bay Plant: New Cartridge Filters

Two new cartridge filters housings helped reduce the pressure drop across the Cartridge filter area.

The changes reduce the pressure drop by ~ 10 psi through the pretreatment and assists in achieving the design capacity of 13,500 m3/day.

It also assists with the high pressure pump performance by providing additional net positive suction head (NPSH)


It also assists with the high pressure pump performance by providing additional net positive suction head (NPSH).

Additional changes to the outlet (converting from 14’ to 16”) piping also resulted substantial reductions in pressure drop.

SWRO Train Number Three Redesign

SWRO Train #3 was completely redesigned, eliminating the less efficient hybrid Calder Pelton Wheel/ ERI PX Cascade Design for a 100% isobaric ERD design with improved manifolds, and low pressure membranes.



E FMembranes

E

D

F

C

G

HP Feed

Pump

ERT

PEPX

M b

HB

GPump

Membranes

AJ

K

Previous Design with ERI PX Cascade Design Utilizing Pelton Wheel


g g g


FE

MEMBRANES

F

CD

FeedPump

Booster Pump G

PX

B HA

PX

Re-Design with ERI PX Cascade


g

SWRO Train Number Six Replacement

When Seven Seas took over the plant, Unit Number Six was still operating with the discontinued Dupont B10 permeators which deliver exceptional permeate quality but at very high feed pressures (1000 PSI +) with very high


permeators which deliver exceptional permeate quality but at very high feed pressures (1000 PSI +) with very high energy consumption. .

SWRO Train Number Six Replacement

New SWRO Train Six operating.


This unit was replaced with a 100% isobaric ERD design with improved manifolds, and low pressure membranes

Cay Bay: New 2nd Pass BWRO Units

The two existing second pass brackish water reverse osmosis (BWRO) units (hollow fiber) have been replaced with


g p ( ) ( ) pnew high recovery units.

Old BWRO units operated at 81% recovery and the new units operate at 95% recovery.

CUPECOY PLANT DETAILSCUPECOY PLANT DETAILSCupecoy Plant Capacity:

•Actual: 1,003,200 US Gallons per Day (3,800 M3/D)

•Contract: 792,000 US Gallons per Day (3,000 M3/D)

•Partial second pass.

Product Quality:

•Actual: <280 uS/cm

•Contract: <300 uS/cm

Power Consumption:

•Actual: ~11 kWh / KIG

•Design: ~11 kWh / KIGDesign: 11 kWh / KIG

Schedule

•Contract Award 7/30/07.


•Plant Operational 1/8/08.

•Less than five (5) Months to Complete from contract award to water production

1 MGD SWRO Cupecoy Plant


Public / Private PartnershipThe Cay Bay and Cupecoy Plants provides a total of 17,300 M3/D (4,567,300 US Gallons per Day) of desalted, potable water in a Public /

Public / Private Partnership

( p y) pPrivate Partnership.

The PPP utilizes the best of both the St. Maarten Power & Water Authority (GEBE) and AFH/SSW to provide the lowest cost water solution with the highest possible reliability to St. Maarten.

AFH/SSW guarantees quality and quantity of potable water production as well as responsibility for all costs to maintain the plant.

GEBE and AFH/SSW share operation, engineering, mechanical and technician responsibilities with almost all staffing of the plants by GEBE personnel.

The net result of the various improvements made to the plant under the BOOT demonstrate that a real public/private partnership between a municipal entity and an experienced, financially solid service provider

i ld ti l lt hi i ll th t t d l


can yield exceptional results achieving all the stated goals.

Conclusions and Results

In less than 5 months from the time the water contract was signed a state of the art 3 800 M3 /D SWRO desalination

Conclusions and Results

signed, a state-of-the-art 3,800 M3 /D SWRO desalination system was constructed at Cupecoy under a BOOT arrangement.

SSW t d th i ti l t t C B t it 13 500 M3 /DSSW restored the existing plant at Cay Bay to its 13,500 M3 /D capacity and greatly improving the efficiency with a system redesign.

With the reduced power consumption, the price of water to the St. Maarten government was able to be reduced.

The new Cupecoy plant and a significantly improved Cay BayThe new Cupecoy plant and a significantly improved Cay Bay plant ensure the long-term water needs of St. Maarten.

Additionally, the power demand of the Cay Bay Plant has been significantl red ced c tting carbon and other emissions and


significantly reduced, cutting carbon and other emissions and freeing up valuable resources in the process.

CONCLUSIONS and RESULTS

- In examining the overall lifecycle costs of upgrading and expanding the capacity of an older SWRO plant, taking into account energy consumption, operating costs, equipment replacement and reliability the best re-design may not be inherently apparent.

-After factoring in dependability of design, various savings through efficiency improvement, environmental concerns, and sticking within very strict workplace safety guidelines AFH /SSW decided upon a number of different approaches for the six (6) operational SWRO and two (2) BWRO trainsapproaches for the six (6) operational SWRO and two (2) BWRO trains depending on their condition and other factors.

-Two seawater RO and two brackish water RO units were completely replaced while others had varying degrees of redesign and rehabilitation.replaced while others had varying degrees of redesign and rehabilitation.

-Combined with improvements in pretreat, posttreat, the combination of upgrades helped AFH/SSW more than meet their electrical consumption targets, production capacity, and on-line time.


g , p p y,

PLANT CONCLUSIONS and RESULTS

-The consumption of electricity at Cay Bay from approx 28,470 mWh per year down to 19,162 mWh per year for a net reduction of 9,308 mWh per year or approx 9,300 metric tons of carbon per annum going forward.

- The people of St. Maarten now have a guaranteed supply of water that is produced with reduced energy consumption, greater reliability, a lower cost supply of potable water, and a sufficient quality to meet the needs of the

f S fpeople of St. Maarten now and well into the future.


Questions?.


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