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INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 5, 2011

© Copyright 2010 All rights reserved Integrated Publishing Association

Review article ISSN 0976 – 4402

Received on December, 2010 Published on February, 2011 1019

Investment grading audit of pumping machinery at Mindi, one of the water treatment plants of Visakhapatnam city A case study

Chandraiah.V 1 ,Lakshmi Pathi.B 2 ,Mahamood.V 3 1 Superintendent Engineer, Water Supply and Sewage, Greater Visakhapatnam Municipal

Corporation, Visakhapatnam 2 Deputy Director, Petroleum Conservation Research Association, Visakhapatnam, India

3 Associate Professor, Department of Civil Engineerig,Andhra University, Visakhapatnam [email protected]

ABSTRACT

Pumps are used to pump the fluid from lower level to higher level by using external energy (either Electrical or Mechanical). Generally positive displacement pumps are used for applications where high head and low discharge are required, while centrifugal pumps are used for how head and high discharge. A case study was conducted on centrifugal pumps at Natayyapalem Pump House & Mindi Filtration plant in Visakhapatanam. Conducted series of experiments to record various parameters viz., discharge, pressure, voltage, current, power, power factor and calculated efficiencies and suggested necessary modifications. This study would help other pumping stations being operated by GVMC and also for similar operating practices adopted in other parts of Indian Urban Local Bodies.

Keywords: Investment Grading, pumping audit, Centrifugal pumps, Experiments, case study

1. Objectives of the Study The Mission of the study is to propose to improve the overall energy efficiency of the Greater Visakhapatnam Municipal Corporation, thus leading to sustainable energy and cost reductions, in water supply segment, which is one in all the four energy consuming segments namely Water, Sewage, Street lighting, and Buildings.

A Study was conducted with the following Objectives: 1. Detailed study of the water segment that is Water Treatment and Pumping System

Pumps and motors at Natayyapalem and mindi water treatment plants, including historical and present energy

2. Quantification of Energy Losses, and Energy Saving Potential. Performance trends, and specific energy consumption.

3. Creation of a database of Baseline Energy Measurements for reference during post implementation measurements and verification.

4. Presentation of Energy Efficiency Measures as Bankable Project and viable installation.

1.1 Water Treatment / Pumping Overview Visakhapatnam is the second largest city of Andhra Pradesh with an area of 550 sqkm, it is primarily an industrial city, apart from being a tourist destination. It is known for its unspoilt beaches, nearby scenic Araku Valley and Borra caves, the 11 th Century Simhachalam temple and ancient Buddhist sites like Thotlakonda and Bavikonda spread across the area. Kailasagiri is the best evening destination of vizagites. The city is home to several state


Chandraia.V, Lakshmi Pathi.B ,Mahamood.V International Journal of Environmental Sciences Volume 1 No.5, 2011

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owned heavy industries; one of the most advanced steel plants and has one of the country’s largest ports and its oldest shipyard. It has the only natural harbor on the eastern coast of India. Due to the presence of the Eastern Naval Command, Steel Plant and HPCL Refinery, the city has been the home to people from different parts of the country and due to this the city has a cosmopolitan nature. The Greater Visakhapatnam Municipal Corporation quenches the thirst of its citizens by drawing water from seven sources of water. These water sources are located in and around Visakhapatnam. The main sources of water are Raiwada Reservoir. Thatipudi Reservoir, Gostani infiltrationwells, Gambheeramgedda, Meghadrigedda, KBR and Yeleru / Godavari river. Each of these water schemes have separate Water treatment plants located at various places. Due to the hilly terrain, the supply and distribution is mostly done on gravity. There are more than 50 major and minor pumping stations for the distribution of water. The details of the locations and the facilities are shown in the appendix. Almost 94% of the pumps installed are of KIRLOSKAR make, 4% are Beacon and 2% are Matter and Platt.

1.2 Megadrigedda Raw Water from this reservoir flows on gravity to Natayyapalem raw water pumping station which pumps to MINDI water treatment plant cum pumping station. The treated water from this treatment plant is pumped to Bulk customers and residential area on the south of Visakhapatnam.

Figure 1:Megadrigedda Scheme



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. Figure 1: Layout of the water distribution scheme

2. Scope of Work

2.1 Scope of Work for Investment Grade Audit (IGA) 2.1.1 Plant machinery under study Natayyapalem pumping station get water from Megadrigedda Reservoir ad water is pumped to mindi filtration plant for treatment. 30 MLD of water is pumped and filtered in these plants for distribution to the citizens in the nearby locality such as Malkapuram and Gajuwaka.

In a broad view, the scope of work for Investment Grade Energy Audit includes, but is not limited to the Following:

2.2 Data Collection & System Mapping

2.2.1 Information collected for each Water Treatment \ Pumping Station

• Total connected load of the Water Treatment \ Pumping systems at Site

• No. of Pumps at Site Categorized by tape and Capacity Rating

• No. of possible combinations for parallel operations of pumps – based on information on present operation philosophy



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• Characteristic Curves of pumps at site, where available

• No. of transformers for the purpose of Water Pumping Systems (Groped by Capacity Rating)

• Electricity consumption for Water pumping system at the municipality – monthly average in kWh

• Maximum Demand of each site – Monthly Average in KVA

• Electricity bills for about 3 Years collected and studied \ summarized for indicators like month wise Unit Consumption, Power Factor, Maximum Demand, Unit cost, Rebates and Penalties availed / levied for each billing period, as period, as per local Tariff Rules of the State / Supply Utility.

• Capacity of the Pumping Station in MLD. 2.3 Pump Study

• Existing efficiency of pump is evaluated by measurements of flow, head, head losses and power

• Operating characteristic curves of pumps are prepared by measurement of all above parameters at various load conditions

• Flow measurement is made by Ultrasonic flow meter. Digital type meters were used to make Head and Power measurement only. Every minute data logging of flow, head and power is made for minimum period of one hour

• Wherever, the flow measurement is not possible with ultrasonic flow meter, the next best method for flow measurement (mechanical) is adopted.

• Recommendations are made to improve the overall efficiency of pumping system

• Review and understand the operational conditions and process of operation of pumping system

• Study of pattern of operation, of individual pumps including no of operating hours of the individual pumps for the past 12 months. Logged details of daily measurements like flow, head, power and power parameters are referred to where available, and used as appropriate, in arriving at conclusions regarding energy saving measures.

• Analyzed design parameters, and actual operational parameters with a view to identify losses.

2.4 Parallel Operation of Pumps

• Found suitability of various pump sets for parallel operation – not restricted to present operation philosophy of the GVMC

• Determines head and power consumption of pumps while running in parallel. Every minute data logging of flow and power is made for a minimum period of 20 minutes

• Studied the parallel operation pumps after assessment of individual performance of pump sets installed at site. No of pumps are operated in



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parallel for study are determined as per actual operating conditions at sites & specifically which pump sets are combined are determined by based on performance data of individual pump sets

• Based on this study, it is suggested best combination(s) of pump sets to be operated for each site

2.5 Electric Motors

• Percentage loading, RPM, load current, unbalance in current & voltage of each motor on exiting load conditions are measured

Recommendations are made for optimizing efficiency of motor

3. Pump set Efficiency Performance Evaluation

3.1 Methodology adopted

• Data pertaining to number of water sources along with their pump stations collected from the GVMC

• Electrical contracted load Vs installed / operational load was compared to arrive at the disparities in the system.

• Collected energy bills from the ULB and converted them to soft form and studies about the contracted demand and actual / billed demand, power factor carried out.

• Studies on Efficiency of pumps installed, head and discharge was conducted.

• Working and loading of Transformers, Motors were recorded.

3.2 Energy Conservation Measures (ECMs) with cost benefit analysis

For each ECM identified, provide a detailed treatment of the Identification and development of ECMs including :

• Existing Scenario

• Proposed Scenario 1. Energy Saving Calculations

2. Annual Energy Savings and related Baseline parameters

3. Details of Technology / Equipment vendors in case of retrofits / system modifications suggested, along with references to product catalogues and quotes attached

4. Cost Benefit Analysis 5. Investment Costs b) Repair and Maintenance Costs

6. Other intermittent or recurring cash flows d) Simple Payback Period 7. IRR calculations

8. Guidelines on M & V for the proposed ECM



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3.3 Energy consumption patterns for the GVMC

It has been assessed that the total consumption of energy and amount paid to power Distribution Corporation by GVMC and following is arrived at. Specific data on Energy Consumption for ULB is not being maintained. However, with the data available with GVMC about the utilization of power over a period of two years has been gathered and computed on the whole the GVMC consumers energy per month to a time of 81.41 MWh out of total energy consumed the water supply has the lion’s share of 55% the next being the sewerage treatment plant as shown Table.1 & Fig.1

Table1:Mwh Consumption/ month per GVMC

S.No Sector Mwh

1 Water Supply 44.78

2 Sewerage Treatment 21.98

3 Buildings 4.88

4 Street lighting 9.79

Total 81.43

As per available information with GVMC the data of consumption of power for last two years for various treatment plant and pumps have been collected and tabulated (ref. table.3, Fig.3&4), Natayyapalem & Mindi works out to be 9% of the annual consumption of power in Water supply, where the case study is conducted.

Table 2: Brief Segment wise Summary of Parameters studied: Water Treatment / Pumping

Focus Area of Study

Primary Parameters

Significant Independent Variables (IV)

Significan t Static Factors (SF)

How the IVs / SFs relate to the Focus

Area

Pump Efficien cy

Head, Flow, Power (Simultaneou s Measuremen ts)

Sump Levels / Aquafer

% of Valve Opening

Per Capita Water Consum ption (lit/day)

Suction head and hence Pump operating point varies with sump levels

Working hours of Pumps and hence saving quantity varies with Per Capita water consumption



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Avg. MWh consumptin / month for GVMC

Water Supply 55%

Sewerage Treatment

27%

Building 6%

Street lighting 12%

Water Supply Sewerage Treatment Building Street lighting

Figure 2: Segment wise Annual Energy Consumption –pie chart

Table 3: Annual Consumption of Power in water supply GVMC in Kwh

S.No Pumping/ Treatment House Consumption Kwn x 10 5 1 PWD 40.00 2 KBR 35.00 3 Thatipudi 24.50 4 TSR 23.50 5 Malliveedu 15.50 6 Gosthani 14.50 7 Seethammadhara 5.50 8 Block15 5.50 9 Mindi 2.50 10 Natayyapalem 14.50

Total 181.00



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PWD 22%

KBR 19%

Thatipudi 14%

TSR 13%

Malliveedu 9%

Gosthani 8%

Seethammad hara 3%

Mindi 1%

Block15 3%

Natayyapale m 8%

PWD KBR Thatipudi TSR Malliveedu Gosthani Seethammadhara Block15 Mindi Natayyapalem

Figure 3: Annual Max. demand for all Pumping Stations / WTP

Annual Consumption of Power in Water supply GVMC in Kwh

0

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

4500000

PWD KBR Thatipudi

TSR Mallivedu Gosthani

Seethammadara Block15 Mindi

Nattayyapalm

Annual Consumption Kwh



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Figure 4: Image showing the scanned copy of monthly bill summary of water pumping station



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Table 4: Existing water pump specifications

S. N o

Name of the Pumping

Stn. / WTP

Pump Type (submersible / VT/ HSCF . Polder etc.)

Make (Pump / Motor)

Motor Rating (kW/H P)

Avg. Operatin g Hrs (hrs/day

)

Total Desig n head (m WC)

Flow (m3/ hr)

Suction /

Dischar ge Size (mm)

Distanc e to which pumpin g is

Supply to

Overh ead

tank or Sump

1 Mindi Centrifugal

HCSF MATHER & PLATT 30 6 18 360 355/27

7 0.004 Overhead

2 Mindi Centrifugal HCSF KIRLOSKAR 18.5 24 9.5

464. 4

385/29 3 0.006

Overhead

3 Mindi Centrifugal

HCSF KIRLOSKAR 18.5 24 9.5 464. 4

385/29 3 0.006

Overhead

4 Natayyapale m

Centrifugal HCSF

KIRLOSKAR 93 24 45 400 436/28 4 2 Sump

5 Natayyapale m

Centrifugal HCSF KIRLOSKAR 93 24 45 400 436/28

4 2 Sump

6 Natayyapale m

Centrifugal HCSF

KIRLOSKAR 93 24 45 400 436/28 4 2 Sump

7 Natayyapale m

Centrifugal HCSF

KIRLOSKAR 93 24 45 400 436/28 4 2 Sump

8 Natayyapale m

Centrifugal HCSF

MATHER & PLATT 93 24 41.2 478 436/28

4 2 Sump

9 Natayyapale m

Centrifugal HCSF

MATHER & PLATT 93 23 41.2 478 436/28

4 2 Sump

Table 5: Existing water pumping / treatment pump set efficiencies

S.No Site Name Pump Type

(submersible / VT/ HSCF . Polder etc.)

Pump Rating (kW/H P)

Suction Valve Position (%

Open)

Discharge Valve

Position (% Open)

Sucti on

Head

Discha rge Head (Mtr)

Total Head (Mtr)

Flow (m3/hr

)

I/P Power (kW)

Effici ency

1 Mindi Centrifugal

HCSF 37 100 20 1 3 4 616.4 8 27.55 18.29

2 Mindi Centrifugal

HCSF 18.5 100 100 1 9 10 266.1 16.06 40.64

3 Mindi Centrifugal

HCSF 18.5 100 100 1 9 10 333.9 3 20.07 40.81

4 Natayyapalem Centrifugal HCSF 93 100 100 0.5 15 15.5 478.8 76.53 25.57

5 Natayyapalem Centrifugal

HCSF 93 100 100 0.5 15 15.5 316.8 77.76 16.65

Table 6: Water pumping / treatment efficiencies for parallel operation combinations

S.No Site Name

Combinati on of Pumps

Rating of Pumps (kW)

Suction Valve

Positions(% Open)

Discharges Valve

Positions (%Open)

Suction Head

Dischar ge

Head (Mtr)

Total Head (Mtr.)

Flow( m3/ hr)

I/P Power (kW)

1 Natayyapalem 47.48 93 100 100 0 41 41 332 160

2 Natayyapalem 48.49 93 100 100 0 39 39 305 166

3 Natayyapalem 49.5 93 100 100 0 39 39 320 169 4 Natayyapalem 47.5 93 100 100 0 39 39 300 172



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3.4 Calculations for suggestions and recommendations Table 7: Replace existing normal pumps with inverter compatible energy efficient pump at

Natayyapalem (93 kW with 40 kW pump) Description Units Formula Value

Measured power consumption of present operating water pump kw A 76.53 93.00

Calculated power consumption of proposed new low head/flow kw B 30 (40) 43

Average Annual operating hrs of one pump (@ 20hrs/day) Hrs C 7300 7300

Annual power savings kwh D=(AB) xC 339669 313900

Power cost (average) Rs/kWh E 4.70 4.70

Recurring annual cost savings Rs F=DxE 1596444 1475330

Onetime cost of implementation for total 2 pumps including piping etc. (estimate) @ Rs. 7,00,000/ Rs. G 1400000 1500000

Payback months H=G/F x12 10.5 12.20

Say 12.00

Table 8: Replace existing normal pumps with inverter compatable energy efficient pump at Mindi (30kW with 15kW pump)

Description Units Formula Value Measured power consumption of present operating water pump kw A 27.55 30.00

Calculated power consumption of proposed new low head/flow kw B 7.55

(15) 15

Average Annual operating hrs of one pump (@20hrs/day) Hrs C 7300 7300

Annual power savings kwh D=(A B)xC 146000 109500

Power cost (average) Rs/kWh E 4.70 4.70

Recurring annual cost savings Rs F=DxE 686200 514650

Onetime cost of implementation for total 2 pumps including piping etc. (estimate) @ Rs. 1,80,000/ Rs. G 360000 375000

Payback months H=G/F x12 6.3 8.74

Say 9.00

Table 9: Replace existing normal pumps (2 pumps) with inverter compatible energy efficient pump at Mindi (18.5kW with 12kW pump)

Description Units Formula Value Measured power consumption of present operating water pump kw A 18.5 18.5

Calculated power consumption of proposed new low head/flow kw B 10 (12) 12

Average Annual operating hrs of one pump (@13.5hrs/day) Hrs C 7300 7300


Power cost (average) Rs/kW h E 4.70 4.70

Recurring annual cost savings Rs F=DxE 291635 223015 Onetime cost of implementation for total 2 pumps including piping etc. (estimate) Rs. G 340000 200000



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Payback months H=G/F x12 14

10.76 Say 11.00

Table 9: Replace existing normal pumps with inverter compatible energy efficient pump at Mindi (37kW with 20kW pump)

Description Units Formula Value Measured power consumption of present operating water pump kw A 37 37

Calculated power consumption of proposed new low head/flow kw B 15 20

Average Annual operating hrs of one pump Hrs C 4198 4198


Power cost (average) Rs/kW h E 4.70 4.70

Recurring annual cost savings Rs F=DxE 434022 335420 Onetime cost of implementation for total 2 pumps including piping etc. (estimate) Rs. G 180000 250000

Payback months H=G/F x12 5 8.94

Say 9.00

Table 10: Brief Abstract (for tables 9 to 12) on Energy Conservation Measures, Bundling of ECMs and Project Development

Estimate of Energy Saving Potential / Annum

Estimate of Costs

Cost benefit Analysis (Rs. In Lakhs)

S N o

ECM Description

Annual Savings (kWh)

Rs. In Lakhs

Investment (Rs. In Lakhs)

Simple Payback

Period month

Location

1 Replace 93kW with 40kW pump

313900 14.75 15.00 12.00 Natayyapale m

2 Replace 30kW with 15kW pump

109500 5.14 3.75 9.00 Mindi

3 Replace 18.5kW with 12kW pump

47450 2.23 2.00 11.00 Mindi

4 Replace 37.0kW with 20kW pump

71366 3.35 2.50 9.00 Mindi

4. Conclusion

After detailed study and the calculations made for the pumps, it is observed that the pump installed at the Water treatment plant is of higher head and discharge. During normal operation, the pump is being operated at 80% throttling loosing valuable energy, wasting money as well as scarce commodity power. It is suggested that the existing pump of higher head and discharge may be replaced with low head high discharge pump. It is suggested to replace 6 Nos pumps at pumping station Natayyapalem & Treatment Plant in Mindi. Under ECM –(Energy Conservation measures) duly studying the parallel pumping, discharge of water, flow rate, age of pumps as well as energy consumed by the pumps under reference the replacement of pumps are highly recommended with possible payback periods for the investment made for the purchase and fixing of pumps. It is suggested that:



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1. 2 Nos of 93 Kw pumps may be replaced with 40 Kw pumps there by the pay back period is one year.

2. 1 No 30 Kw pump may be replaced with 15 Kw pumps there by the pay back period is 9 months

3. 2 Nos. 18.5 Kw pumps may be replaced with 12 Kw pumps for which pay back period is 11 months.

4. 1 No 37 Kw pump may be replaced with 20 Kw pumps there by the pay back period is 9 months

5. By replacing the old pumps, maintenance cost of old existing pumps is avoided and investment made to procure new pump sets would be recovered with in a span of one to two years.

5. References

1. Young, D.L., Liu.,Y.H., Eldho, T.I (1999), Three Dimensional Stokes Flow Solution Using Combined Boundary Element and Finite Element Methods, The Chinese Journal of Mechanics, Vol.15/4, 1999,pp169176.

2. Young, D.L., Liu.,Y.H., Eldho, T.I (2000), A Combined BEMFEM Model for the Velocityvorticity Formulation of NavierStokes Equations in threedimensions, International Journal of Engineering Analysis with Boundary elements, Vol.24/4, 2000, pp 307316.

3. Bansal RK “Fluid mechanics and Hydraulic Machines” Lakshmi Pubications Pvt. Limited, New Delhi – 2005

4. John F Douglas, Janusz M Gaslorek, John A Swaffield “Fluid Mechanics” Pearson Education (Singapore) Pvt. Limited, India Branch, New Delhi – 2005

5. Modi & Seth “Fluid Mechanics Hydraulics and Hydraulic Machines”, Standard Publications, New Delhi

6. Ramadurgaiah D “Fluid Mechanics Hydraulic and Hydraulic machines”.

7. New Age International Pvt.Limited Publishers, New Delhi

8. Eldho, T.I., (2003) Remediation of Contaminated Ground Water, Scope of Onsite Pump and Treat Technology, Institutions of Engineers India, Civil Engineering Journal, May 2003.

9. Rao. B.V., Eldho, T.I., (2003), Significance of Sumps, Times Journal of Fluid Power, July 2003, pp 2023.

10. Eldho, T.I ., Anupam K.Singh, (2003) Cultivating water, Time Agriculture Journal, MayJune 2003, pp 2629

11. Sharief, SM.V., Eldho T.I., and A.K Rastogi, (2008), Optimal Pumping Policy for Aquifer Decontamination by Pump and Treat Method Using Genetic Algorithm, ISH, Journal of Hydraulics Engineering, vol.14 (2), pp 117.



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12. Deepa D., and Eldho, T.I., (2009), effect of Spacing of Two Offiset Jets on Scouring Phenomena, Journal of Hydraulic Research, IAHR, Vol.47, pp 8289.

investment grading audit of pumping machinery at … grading audit of pumping machinery at mindi,...

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