development of cost functions for sewage treatment plant

8/2/2019 Development of Cost Functions for Sewage Treatment Plant

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WELCOME


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WELCOME


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DEVELOPMENT OF COST

FUNCTIONS FOR

SEWAGE TREATMENT

PLANT

A DISSERTATION REPORT ON


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GUIDED BY:


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Steps in Design of aSewage Treatment Plant

Collection of Field DataFeasibility Study

Functional Design

Structural Design


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Functional Design Considerations

Nature of Waste

Volume of Waste

Effluent Standards

Expertise available for Design, Construction and

Operation

Ease of Construction and Design of STP

Degree of Treatment Required

Capital investment


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COST OF A STP..??

Initial Cost Recurring Cost


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Selection of a treatment process

FunctionalVariables

Influent and

Effluent

Standards

Environmental

and Meteoro-

logical

conditions

Process

efficiency

Technical

Variables

Equipmentsavailable

Energy for

operation

Experience& Expertise

Financial

Constraints

Initial

Investment

Operational

Cost


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Selection of a Process based

on Cost Comparison

Major Objective of the study

To develop a tool for rough cost estimates of a STP.


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CONSTRAINTS:

Wide number of Treatment Processes

Wide variation in Capacity of STPs

Wide range of Equipments

Variation in Rates


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Generalization of Problem

Taken only one process i.e. Activated Sludge Process

Most Widely Used

Breakup of ASP in components

Mechanical Equipment

Civil Works

Breakup of Civil Structures in Shapes

Circular

Square

Rectangular


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Fixing of Shape of Civil Works

Most Common Shapes

CircularSquare

Rectangular

Rectangular with Width:Length Ratio : 1 : 1.5

Rectangular with Width:Length Ratio : 1 : 2


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Fixation of Size/Capacity ofCivil Works

Study of a number of Treatment Plants in India


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Source : Performance Evaluation of Sewage Treatment Plants in India, NEERI Report, 1991.

Legends: S - Screening GR - Grit Removal PS - Primary Settling

ASP - Activated Sludge EA - Extended Aeration TF - Trickling FilterSS - Secondary Settling OP - Oxidation Pond


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Size of Units of ASP

Circular Diameter : 2 to 40m

Square Side : 1 to 15m

Rectangular

Longer Side : 1 to 15 m for both aspect ratios


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Collection of Data For

Mechanical Equipments

Only General Purpose Equipment Taken

Floating Aerators Fixed Aerators

Clarifier and Clariflocculator Equipment

Pumps etc.

Rates colleted form three different vendorsfrom different locations


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Development of Cost Functions

for Civil Structures

Structural Design

Using SEPL Tank Software

Estimation and Cost Calculation

Using Microsoft Excel Worksheet

Development of Cost Functions

Using Microsoft Excel


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Design of Circular Tank


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CIRCULAR TANKS

Dia of tank 25.00 m

Wall height above foundation 4.20 m

Wall Thickness (top) in mm 200 mm

Wall Thickness (bottom) in mm 200 mm

Length of Toe 0.60 m

Thickness of Toe in mm 150 mm

Length of Heel 0.90 m

Thickness of Heel im mm 150 mm

Thickness of Base Slab 150 mm

Qunantity of Concrete in Walls = 66.501 m3

Quantity of Concrete in Toe = 7.351 m3

Quantity of Concrete in Heel = 10.221 m3

Quantity of Concrete under wall= 2.375 m3

Qty. of Concrete in Base Slab = 63.410 m3

Total Concrete = 149.859 m3

PCC = 83.36 m3

Calculation of Quantities

Estimation of QuantitiesConcrete


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Estimation of QuantitiesSteel

Dia Spacing Number Length Quantity

mm mm m kg

Reinforcement

Walls (Horizontal Reinforcement both faces) x2

8 13 79.168 811.166 kg

10 14 79.168 1364.943 kg

12 12 79.168 1684.729 kg

16 79.168 0.000 kg

Walls (Vertical Reinforcement - Both faces)

8 175 4.700 324.132 kg

8 175 4.700 324.132 kg

Extra (Vertical Reinforcement )

8 175 3.000 206.893 kg

8 175 2.000 137.928 kg

8 175 1.000 68.964 kg

Foundation (RADIAL top of Heel & Toe)

8 260 302 2.000 238.025 kg

Foundation (RADIAL bottom of Heel & Toe)

8 210 374 2.000 294.773 kg

Foundation (Circumfrencial top & bottom of Heel & Toe)

8 290 6 78.069 184.592 kg

Base Slab All four faces

8 290 332 18.075 2364.843 kg

Haunch

10 393 1.000 241.991

Total Steel (kg) = 8247.111 kg

Add 5% Wastage & Lap= 412.356 kg

Total Steel (kg) = 8659.466 kg

Calculation of Quantities

CIRCULAR TANKS


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Cost of a Circular Tank

Dia of Depth Capacity Total Cost Cost in Cost/Liter

Tank (m) of Tank (m) cum in Lacs Rupees

2.00 1.70 5.34 0.10 10125.29 1.90

3.00 2.20 15.55 0.21 21179.20 1.36

4.00 2.70 33.93 0.34 34163.99 1.01

5.00 3.20 62.83 0.52 52029.27 0.83

10.00 3.20 251.33 1.37 137494.75 0.55

15.00 3.20 565.49 2.49 249046.73 0.44

20.00 3.70 1162.39 4.22 422409.96 0.3625.00 4.20 2061.67 7.01 701168.03 0.34

30.00 4.70 3322.23 11.10 1109622.37 0.33

35.00 4.70 4521.93 14.82 1482128.43 0.33

40.00 5.00 6283.19 20.28 2027925.98 0.32

COST OF CIRCULAR TANKS


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Cost Function for a Circular Tank

Circular Tanksy = 0.0256x0.743

R2 = 0.9962

0

5

10

15

20

25

0 1000 2000 3000 4000 5000 6000 7000

Capacity of Tank (cum)

Costin

Lacs


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Variation of Cost w.r.t. Capacity

Circular Tanks

0

5

10

15

20

25

0 1000 2000 3000 4000 5000 6000 7000


Costin

Lacs

0

0.5

1

1.5

2

2.5

Costperliter

Total Cost Cost/Liter


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SQUARE TANKS

Side of Depth Capacity Cost Cost Cost/Lit

Tank of Tank cum in Lacs Rupees

1.00 1.20 1.20 0.05 5283.94 4.40

2.00 1.70 6.80 0.14 13756.80 2.02

2.00 2.20 8.80 0.16 16169.85 1.84

3.50 3.20 39.20 0.48 47590.30 1.21

5.00 2.20 55.00 0.54 53689.10 0.98

5.00 3.20 80.00 0.91 90532.41 1.137.50 3.20 180.00 1.56 156078.63 0.87

10.00 3.35 335.00 2.65 264924.21 0.79

12.00 4.00 576.00 4.76 476323.79 0.83

14.00 4.70 921.20 7.61 760704.97 0.83

15.00 5.00 1125.00 10.25 1024861.08 0.91

COST OF SQUARE TANKS


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Cost Function for Square Tanks

Square Tanksy = 0.032x0.7776

R2 = 0.9863

0

3

6

9

12

0 200 400 600 800 1000 1200


Costin

Lacs


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Cost Variation of Square Tanks

Square Tanks

0

2

4

6

810

0 200 400 600 800 1000 1200


Costin

Lacs

0.00

1.00

2.00

3.00

4.005.00

Costperliter

(Rs.)

Cost

Cost/Liter


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Cost Function for Rectangular TanksAspect Ratio 1: 1.5

Rectangular Tanks 1 : 1.5

0

2

4

6

8

0 200 400 600 800

Capacity of Tank in cum

CostinLacs

0.00

1.00

2.00

3.00

4.00

Costperliter

(Rs.)

Cost

Cost/Lit


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Cost Function for Rectangular Tanks

Aspect Ratio 1: 2


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Cost Comparison based on

Shape of Tanks

TanksComparision of Cost for Different Shapes

0

2

4

6

8

0 100 200 300 400 500 600 700 800

Capacity in cum

C

ostin

Lacs

1:1

1:1.5

1:2

Circular


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Material Cost AnalysisCircular Tanks

Concrete

53%

Other

25%

Steel

22%

Square Tanks

Other

13%

Steel

29%

Concrete

58%

Rectangular Tanks 1.5

Concrete

54%

Steel

33%

Other

13%

Rectangular Tanks 2

Concrete

52%

Steel

35%

Other

13%


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COST FUNCTIONS FOR

MECHANICAL EQUIPMENTS

Floating Aerators

Fixed Aerators

Clarifiers

Clariflocculators

Clarifier Scraper Arm

Centrifugal Pumps

Floating Aeratorsy = 0.9718x

0.4957

R2

= 0.9433

0

3

6

9

12

0 20 40 60 80 100 120

HP

Costin

La

cs

Fixed Aerators y = 0.3152x0.6405R

2= 0.9073

0

2

4

6

8

10

0 20 40 60 80 100 120

HP

CostinL

acs

Clarifiersy = 0.6274x

0.7749

R2

= 0.9547

0

4

8

12

16

0 20 40 60

DIA (m)

CostinLacs

Clariflocculator y = 0.8213x0.7394R

2= 0.9769

0

5

10

15

20

0 10 20 30 40 50 60

DIA (m)

CostinLacs

Clarifier Scraper y = 0.3107x0.8098R

2= 0.9767

0

2

4

6

0 10 20 30 40

DIA (m)

CostinLacs

Centrifugal Pumps y = 0.0828x0.9794R

2= 0.9746

0

5

10

15

0 50 100 150 200

HP

CostinLacs


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COST COMPARISION WITH

ACTUAL COST

Comparision with Actual Cost

0.00

10.00

20.00

30.00

40.00

50.00

STP Dharamshala STP Jawalamukhi

Total Cost from

Cost Functions

Actual Cost of

Justification


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CONCLUSION

The Cost Functions developed in the

present study can be used as a decision

support system for having a quick idea of

expenditure involved in construction of a

Sewage Treatment Plant.


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CONCLUSION

These cost functions not only provide cost

of Conventional ASP but for all treatmentfacilities where these shapes are

encountered.

Hence the designer can compare the cost of twodifferent processes with this decision support

system.


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CONCLUSION

With the developed cost functions, the

designer can choose the shape of thetreatment unit based on cost comparison.


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CONCLUSION

Cost functions developed show that

Circular Tanks have least costand hence

recommended.

Cost of Reinforcement is the major factor

for increase in cost for square and

rectangular tanks.


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Recommendations for Future Work:

Need to integrate with the software for

Functional Design of a treatment process.


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The work may be extended in the form of

an Expert System where the treatmentprocesses may be optimized on cost basis


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Some specialized software may be

developed/procured from market for design

of Square/Rectangular Tanks with sides

greater than 15m for refinement of this

study.


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THANKSTO ALL OF YOU !!!


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THANK-YOU

ONCE AGAIN

development of cost functions for sewage treatment plant

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