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Research

Research. The Revenue Effect of Inefficient Potable Water Meters on a Water Utility Co. Background. “For many years, utilities and water professional researchers have been trying to determine the optimum time for meter replacement with no conclusive answer ” Davis , 2005, p. 3.

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Research

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  1. Research The Revenue Effect of Inefficient Potable Water Meters on a Water Utility Co

  2. Background “For many years, utilities and water professional researchers have been trying to determine the optimum time for meter replacement with no conclusive answer” Davis, 2005, p. 3

  3. Significance of the Study • Serve as measurement units and cash registers in any modern water-conscious utility. • The majority of water utilities throughout the world provide their customers with water meters to measure their potable water consumption. • Inaccurate meters tend to under-register consumption volumes and therefore a water utility should monitor closely customer consumption trends to identify meters that have lost accuracy. • The primary purpose: to provide a basis for water user fees for the majority of the utility’s revenue

  4. The National Water Commission • Non Revenue Losses are approx 68% • Suffers from the inability to recover the full cost of service from consumers, partly due to inadequate tariffs as well as excessive losses and inefficiencies. (Smith, 2011, p. 6).

  5. The National Water Commission • Water production: 24.09 billion Litres • Billed volume: 8.18 billion Litres • LOSSES15.91 billion Litres Physical Leaks, Overflows… Theft, Acc. Errors Meter Errors… Apparent

  6. The Water Company • Active Customer base: 334,337 • Possessing meters: 277,708 • Meter age range: 0-20 years • Done some amount of study to categorize the real or physical losses such as systems loss. • Has not undertaken a comprehensive study in the levels of apparent loss arising from inefficiencies in measuring the volume of water consumed by its customers.

  7. Literature Review For many years, utilities and water professional researchers have been trying to determine the optimum time for meter replacement with no conclusive answer. “Nominally, most water utilities have used a range of service between 10 and 20 years for meter replacement due to the perceptionof decreasing meter accuracy with length of service” (Davis 2005)

  8. Literature Review Generally Litterature Review highlights theses problems: • The wearing of meter measurement components over time. • The accumulation of sediments and scales from lime deposit. • Orientation in installation. • Impurities in the water (Quality) • Inappropriate sizing of meters

  9. Literature Review • While real losses are physical losses and a cost to the water utility, apparent losses are not physical but financial losses. • WHY? …. because the product was delivered to the customer but not accurately measured. (Julian et al. (2008) (Fantozzi, Criminisi, Fontanazza, Freni, & Lambert,2003)

  10. Literature Review Significant Study With the age of the meter kept constant at 10 yrs) ….substantial decrease in accuracy with increasing cumulative volume appears to be the primary factor that ultimately drives the need for meter replacement. (Davis 2005)

  11. Problem Statement • The volumetric measurement of water consumption by customers of the Water Utility is an issue that requires serious policies and standards. Such policy will involve changing water meters that has outdone their useful life based on established guideline. • The level of apparent water loss by meter inaccuracy is not known and therefore the company cannot make decisions based on a cost benefit analysis.

  12. Purpose of the Study • The purpose of this study is to examine the effects of aging meters and their inaccuracies on the revenue of the Water Utility. .

  13. Theoretical Framework • Like any machinery, potable water meters lose their efficiency over time. • It is estimated that within a six year time span, registration errors (under-registration) due to loss in efficiency ranges from 3-10%. (Farley & Trow, 2003,  p.7).

  14. Meter Types Single Jet Nutating Disc Multi Jet

  15. Meter Types • ADVANTAGE • Good at low flow • DISADVANTAGE • Affected by suspended solids • Larger and heavier than equivalent meters • More expensive than equivalent meters https://video.search.yahoo.com/search/video;_ylt=A2KLqIUFzxRTQREA0nP7w8QF;_ylu=X3oDMTBrcXU2aHFlBHNlYwNzZWFyY2gEdnRpZANWMTQ5?p=multi+jet+water+meter+principle&ei=utf-8&fr=yfp-t-901

  16. CaCo2 Deposit Meter Accuracy 1/8 inch deposit

  17. What Pairs are Saying • Arregui et al. (2006) therefore indicated that the metering errors at low flow rates are higher than errors at high flow rates. • According to Arregui et al. (2006) findings, the metering errors for volumetric meters will only tend to go negative as the age or cumulative flow becomes greater.

  18. Meter Decay with Cumulative Volume

  19. Typical Decay Error Curve Adapted from Arregui, Cabrera and Cobacho, 2006, “Integrated Water Meter Management,” p. 140

  20. Research Question • What is the economic age for the replacement of water meters? • What revenue loss is incurred through aged meters?

  21. Limitations • Company does not remove meters for sample testing. • Difficult to determine whether it was installed as a new meter or a retrofitted one. • Poor data integrity ; difficulty ascertaining the age of the meters

  22. Instrument • Meters were tested using a fixed meter test bench (calibrated to the American Water Works Association (AWWA) standards) • Procedure…..

  23. Instrument

  24. TEST • Qmin, Qt and Qmax • maximum admissible error narrows from +/- 2 % to +/- 5% • Low Flow (Qmin) ¼ gal. per minute (gpm) or 59.5 L/hr • Transition Flow (Qt) 2 gal. per minute (gpm) or 477 L/hr • Maximum Flow (Qmax) 20 gal. per minute (gpm) or 4,542 L/hr

  25. Research Design • Dependent variable (meter accuracy) • Independent variable (meter age). • Subsequently changed to cumulative volume as a representation of the age of each meter. • For this research, the samples for testing was taken from a surface water supply

  26. Models Tested • SR • SR2 • T10

  27. RESULTS

  28. Typical Results from Research Investigation

  29. Results • The overall results of all (131) the meter tested were analyzed using the software, Statistical Programme for Social Science (SPSS). • The percentage under registration at each test level along with the cumulative volume for each meter were entered into the SPSS database for processing of the following statistical analyses

  30. Results

  31. Number of Meters that Failed the AWWA Test Standard

  32. Failure by percentage range

  33. SR SR2 T10

  34. Descriptives

  35. Correlation Analysis

  36. Correlation Coefficient by Model • SR -0.504 after Failed meter removal –0.746 • SR2 -0.146 after Failed meter removal -0.593** • T10 -0.017after Failed meter removal -0.017

  37. SR Model

  38. SR2 Model

  39. T10 Model

  40. Number of Meters Within the Company that has Cumulative meter reading exceeding 500,000 litres

  41. Research Question 1. • What is the economic age for the replacement of water meters? NB Meter with lowest recorded cumulative volume failed all three test

  42. Research Question 1. • Cumulative volume rather than age will be the recommendation for determining the replacement • From study(81 or 62%) had recorded volumes lying within the 500,000 to 1,000,000 litre range.

  43. Results

  44. Research Question 1. • A conservative recommendation would be to replace meters that has recorded Estimated number of years based on 23,000 litres per month average usage.

  45. Research question 2: What revenue loss is incurred through aged meters? • There are 2155 meters that has exceeded the 1 million litremark in their service life. • Assuming that all these are SR2s (most dominant in the field).

  46. Research question 2: • What possible revenue loss is incurred through aged meters? • 23000 x 2,155 = 49,565,000 Litres/month • Estimating an 11.36% loss….The true volume = 1.1136 x 49,565,000 = 55,195,584 Litres • Estimated Apparent Loss through meter error= 6,352,193L • Estimated Revenue loss at 32cents/litre = $2,032,701.81/mthor • $24,392,421.66 annually

  47. Research question 2: • ROI • Current average replacement cost of a domestic meter is $8,260.00. • Average monthly domestic revenue is approximately $7,950.00 • ROI for the average customer would be approximately one month

  48. Conclusion • The general results for all three models indicate that all the meters tested were least efficient in their performance at the low flow range. • The T10 model is the most reliable • The SR model is the least performing meter

  49. Recommendations • Implement a meter replacement policy using cumulative volumetric threshold as the basis for replacement. • Further cross sectional studies will be necessary to discover other interesting dynamics such as: • CaCo2 levels in each supply zone • Research the effects based surface vsundeground supply. • Indirect supply via storage tanks that are sucseptable to low flow • Consider Investing more in the T10 model

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