costing summaries for selected water treatment processes

Costing Summaries for Selected Water Treatment

Processes

Alix MontelEcole Centrale de Nantes

M. Robin CollinsDepartment of Civil Engineering

University of New Hampshire

Acknowledgment

Project funded from USEPA to the

University of New Hampshire Water Treatment Technology

Assistance Center

Develop Costing Curves for :

• Construction

• Operation and Maintenance

Small Systems

• Limited financial means

• Economy of scale

Economy of Scale(Clark, 1987)

DESIGN CAPACITY

UNIT

CO

ST

1−= βα nn

c QQC

A Reference For :• Small Water Utility Decision-

Makers

• Engineering Consultants

• Facility Operators

Treatments Considered :

• Slow Sand Filtration

• Ceramic Media Pressure Filtration

Slow Sand Filtration

Ceramic Media Filtration

Methodology

Collect Data From:

• Engineering Consulting Companies

• Facility Operators

• Facility Public Works Departments

Questionnaires

• Construction Costs

• O&M Costs

• General Design and Operational Information

Update The Costsfor year 2000

• Engineering News-Record Construction Cost Index

• Consumer Prices Index

• Year Index = average of the monthly values of the year

)()()()(

yyearIndexCostxyearIndexCostyyearCostxyearCostUpdated ×=

1920,19601924,1952,1966

193519551997199619941975199319931993

1992-94199319951994

1997-981992199519961990

50442.421

0.354.8

0.0361

0.30.60.31.2

0.450.61

0.3750.71

0.341

46452

18582787929754

468282

765335962279

1605576564491976

3071374

West Hartford CT.Springfield MA.Greenfield MA.W.Springfield MA.Hatfield MA.Derby VT.Rutland VT.McIndoe Falls VT.Livermore Falls ME.Eagle Lake ME.Winthrop ME.Mars Hill ME.Madison ME.Milo ME.Newport ME.Sunapee NH.Newport NH.Hillsborough NH.Barlett NH.Gorham NH.

Year of Construction

Design Capacity (mgd)

Filter Area (sq.m.)

Facility

20 Slow Sand Filters Surveyed

• 19 of the 20 covered

• design capacity from 0.036 to 50 mgd

• total filter area from 82 to 46,452 m2

• 15 of them built in the 1990s

CONSTRUCTION COSTS

Design ParameterNormalization

• Filter Area

eliminatesdifferences in filtration rates between the plants

• Design capacity

allows to achieve a comparison with other technologies

*1000 m3/hr = 6.34 mgd *Typical Design Value : 0.12m/hr=0.05gpm/sq.ft

Design Capacity versus Filter Area (design filtration rate)

Q = 0 . 1 7 *A

Q =d e s i g n c a p a c i t y ( m 3 / h r )

A =f i l t e r a r e a ( m 2 )

R 2 = 0 . 9 9

0

1 0 0 0

2 0 0 0

3 0 0 0

4 0 0 0

5 0 0 0

6 0 0 0

7 0 0 0

8 0 0 0

9 0 0 0

0 1 0 0 0 0 2 0 0 0 0 3 0 0 0 0 4 0 0 0 0 5 0 0 0 0

FILTER AREA, m 2

DES

IGN

CA

PA

CIT

Y,

m3/

hr

a v e ra g e f i l t ra t i o n ra t e Q / A =0 . 1 7 m/ ho ur

Total Cost(updated for year 2000)

0 .E+0 0

1 .E+0 6

2 .E+0 6

3 .E+0 6

4 .E+0 6

5 .E+0 6

6 .E+0 6

7 .E+0 6

8 .E+0 6

0 1 0 0 0 2 0 0 0 3 0 0 0 4 0 0 0 5 0 0 0

FILTER AREA, m2

C O

N S

T R

U C

T I

O N

C O

S T

, $

Cc=1267.2A +1000000Cc=construction cost($)

A =f ilter area (m2)R2 = 0.90

Construction Cost Variability

• Site conditions• Water storage size variation• Facility influent and effluent

piping

Comparison with a Previous Studyby Berg, Tanner and Shied, Slow Sand Filtration, ASCE, 1991

all costs updated for year 2000

0.0E+00

1.0E+06

2.0E+06

3.0E+06

4.0E+06

5.0E+06

6.0E+06

7.0E+06

8.0E+06

0 1000 2000 3000 4000 5000

F I L T E R A R E A, m 2

C O

N S

T .

C O

S T

,$

.

our data

previous survey

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

0 1000 2000 3000 4000 5000

F I L T E R A R E A, m 2

UN

IT C

O S

T, $

/m2

Cc = construction cost ($)A = filter area (m2)

R2 = 0.75

Unit Cost(updated for year 2000)

-0.5760A125400 =Cc/A ×

O&M COSTS

Actual Water Flow/Design Capacity

Wf = 0.8842*Q - 0.3409

0

5

10

15

20

25

30

35

40

45

50

0 10 20 30 40 50 60

DESIGN CAPACITY, mgd

AC

TUA

L W

ATE

R F

LOW

, mgd

.

Unit Cost

O&Mc = Operation and Maintenance Cost ($)Wf = Actual treated water flow (mgd)R2 = 0.39

O&Mc/1000 gal = 0.571xWf-0.471

0

1

2

3

4

5

6

7

8

0 10 20 30 40 50

ACTUAL WATER FLOW , m gd

O&

M C

OS

T, $

/100

0 g

al

Budget Composition

• Chemicals• Electricity• Labor• Sand replacing

Livermore Falls

3%

4%

2%

91%

chemicals

electricity

labor

?

example

Chem icals, Electricity and Labor Cost

Cos t = 42109.W f + 15037R2 = 0.99

0.00E+00

2.00E+05

4.00E+05

6.00E+05

8.00E+05

1.00E+06

1.20E+06

1.40E+06

1.60E+06

1.80E+06

2.00E+06

0 5 10 15 20 25 30 35 40 45 50

A C T U A L W A T E R F L O W , m gd

Ch

em

., E

lec.

an

d L

abo

r C

ost

, $

.

Chem icals, E lectricity and Labor Cost (zoom )

Cos t = 53620.W f + 11541R2 = 0.95

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

200,000

0 0.5 1 1.5 2 2.5 3

A C T U A L W A T E R F L O W , m g d

Che

m.,

Elec

. and

Lab

or C

ost,

$

Unit O&M Cost

Uo& m = 0.19W f-0 .27

R2 = 0 .44

0

0 .1

0 .2

0 .3

0 .4

0 .5

0 .6

0 1 2 3 4

Actu al W ater F low , m g d

Uni

t O

&M

Cos

t, $

/100

0gal

.

Operation and Maintenance Costs

O&Mc = 1 56748*Q0.5 2 1 1

O&Mc=O&M cos ts ($ )

Q=des ign capacity (mgd)

R2 = 0.4346

1 00

1 000

1 0000

1 00000

1 000000

1 E+07

0 .0 1 0 .1 1 1 0 1 0 0DESIGN CAPACITY (m gd)

O&

M C

OS

TS

($) h

s

hsh

hh

s

rhs or r

rs s

cleaning methods

s : s cr apingh: har r owing

r : r aking

s

O&M Costs Variability

• Raw water quality

• Wages

• Gravity versus pumping

0.1781997Grand Isle, VT

0.3601996Goffstown, NH

0.0601997Swain’s Lake, NH

0.0601995New Hampton, NH0.1201993Contoocook, NH

Design Capacity (mgd)

Year of construction

Facilities

Ceramic Media Filters

5 Filters surveyed

• built in the 1990s

• design capacity from 0.06 to 0.36 mgd

Construction Cost

• building cost– updated with ENRCCI

• equipment cost– updated with CPI

Total Construction Cost Versus Design Capacity

C c = 3 E + 0 6 x D c + 2 2 3 8 0 6C c = c o n s tr u c tio n c o s t ($ )

D c = d e s ig n c a p a c ity (m g d )R 2 = 0 .9 9

2 .0 0 E + 0 5

3 .0 0 E + 0 5

4 .0 0 E + 0 5

5 .0 0 E + 0 5

6 .0 0 E + 0 5

7 .0 0 E + 0 5

8 .0 0 E + 0 5

9 .0 0 E + 0 5

1 .0 0 E + 0 6

1 .1 0 E + 0 6

1 .2 0 E + 0 6

0 0 .0 5 0 .1 0 .1 5 0 .2 0 .2 5 0 .3 0 .3 5 0 .4

D E S IG N C A P A C IT Y (m g d )

TO

TA

L C

ON

ST

RU

CT

ION

CO

ST

($)

.

Unit Cost Versus Design Capacity

Cc/Q = 1.8999 Q-0.4203

Cc/Q=unit cost ($/1000 gal)Q=design capacity (mgd)

R2 = 0.95

22.5

33.5

44.5

55.5

66.5

7

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

Design Capacity, mgd

Un

it C

ost

, $/g

pd

.

O&M COSTS

O&M Cost

0.3422,500180,000200,000Contoocook

Normalized Budget$/1000 gal

Total O&M budget ($)

Actual Treated Flow (gpd)

Design Capacity(gpd)

Facility

Modeled Slow Sand Filtration O&M Cost = $0.30/1000 gal

Construction Costs Comparison

Membrane Filtration



0

1

2

3

4

5

6

0 1 2 3 4 5 6

Design Capacity, mgd

Uni

t Con

stru

ctio

n C

ost,

$/gp

d

0

0.1

0.2

0.3

0.4

0.5

0.6

0 1 2 3 4

Actual W ate r Flow , m gd

Uni

t O

&M

Cos

t, $

/100

0gal

.O&M Costs Comparison



CONCLUSIONS

• Covered constructed slow sand filters – more expensive than ceramic media filters– more expensive than membrane filtration

filters for small design capacities– cheaper alternative for larger capacities

• Not enough data collected to achieve an O&M cost comparison

costing summaries for selected water treatment processes

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