2.2. unipa vincenza notaro - management of apparent losses

2nd AQUAKNIGHT Conference,
21 May 2014, Aqaba, Jordan
Vincenza Notaro, UNIPA1
Management of Commercial Losses
Vincenza Notaro, UNIPA
vincenza.notaro@gmail.com
2nd AQUAKNIGHT Conference
"Water Loss Management in the Mediterranean
Countries:
the AQUAKNIGHT Project Results“

Apparent Losses
…..Apparent losses are the nonphysical losses
that occur when water is successfully delivered
to the customer but, for various reasons, is not
measured or recorded accurately.…
AWWA MANUAL M36

Apparent losses
The main components of apparent losses are:
 unauthorised consumptions
 meter reading and billing errors
 meter under-registrations →
3
Metering errors are caused by intrinsic
inaccuracies affecting the water meter

Unauthorized Consumption Components
• Illegal connections;
• Open bypasses;
• Buried or otherwise obscured meters;
• Misuse of fire hydrants and fire-fighting systems (unmetered
fire lines);
• bypassed consumption meters (meter tampering);
• Illegally opening closed valves on customer service piping that
has been shut off for non payment;

Illegal Connection Example
For expenditure analysis unauthorized consumptions in the Water Balance can
be put equal to 0.25% of Water Supply (representative value from water audit
worldwide)
Illegal consumption can be higher where economic conditions are poor

Systematic data handling Errors
Data transfer errors
– Manual meter reading errors
– AMR equipment failure
Procedural/data entry errors during meter change-outs
– Data analysis errors
– Use of poorly estimated volumes in lieu of meter readings
Policy and procedure shortcomings
– Delays in registration, metering or billing operations

Water meter intrinsic error
Despite their importance, water meters are characterized by intrinsic
inaccuracies that change with the flow rate passing through the meter.
UNIPA
Q1 Q2 Q3 Q4
-20%
-40%
-60%
-80%
-100%
ε1 ε2
Flow rate [l/h]
Error
ISO 4064:2005
Q1 ≤ Q < Q2 → ε ≤ ε1 = 5%
Q2 ≤ Q ≤ Q4 → ε ≤ ε2 = 2%
Performance curve of a new water meter

Meter performance is related to:
•the TECHNICAL FEATURES OF THE METER
•the METER WEARING PROCESS (METER AGE)
•the WATER QUALITY
•the NETWORK PRESSURE
•the TEMPORAL PATTERN OF END USER DEMAND
UNIPA

Influence of user’s consumption
Generally, the apparent losses due to meter under-registration are related to the
percentage of user’s consumption occurring at low and very low flow rates.
UNIPA
A class C water meter with Qn = 1,5 m3/h can have a starting flow equal to 5-10 l/h
thus theoretically the 7% of consumption should be not registered
The percentage increases with water meter aging and wearing process.
Flow rate (l/h)
%ofuserconsumption

Consumption at low flow rate can be due to:
• leaks inside the households, usually in faucets and
toilets
• private domestic storage tanks
– The filling of the tank is produced through a
proportional ball valve which laminates the
instantaneous water demand and reduces flow
rates
UNIPA

User’s storage tanks
User’s storage tanks interposed between the revenue meter and the end user can
affect the share of consumption at low flow rates
This supply scheme is very common in the Mediterranean where water shortage
often happens and the intermittent water supply is a common practice.
Private
roof tank
Network
Revenue
water meter
Float valve
User fixtures
and appliances

The float valve
• The float valve dampens the instantaneous water demand and
reduces the flow rate of water passing through the meter.
• Slow closure of the float valve reduces flow rates passing
through the meter and so increasing metering errors.
12
Rizzo and Cilia (2005)
When an old revenue meter
is coupled with a private
water tank, it may not
register even more than the
50% of the volume passing
through it

Typical Consumption Pattern for different
households
Household Type I: Apartment blocks with direct injection from the network or a pump
(tested N° 389 for a week).
Household Type II: Apartment blocks fed from an elevated tank (at the top of the
building). Water meter is installed upstream the tank. Tested N° 58 households for a
week.
Household Type III: Independent houses with garden. Tested 34 households for 4 weeks
Arregui, F.J.* et all. Reducing Apparent Losses Caused By Meters Inaccuracies

Calculate weighted error
Arregui, F.J.* et all. Reducing Apparent Losses Caused By Meters Inaccuracies
Multiply the percentage of water consumed in a flow range by a user and the average
error at the medium flow rate of the flow interval

Apparent Losses and Roof Tanks
Upstream
Downstream
UpstreamUpstream
DownstreamDownstream
Research in Malta has conclusively
shown that even with new Class D
(Qn=1.0m3/HR) meters, between 5 to
10% of water consumed is not
registered by the meters.
Upstream Downstream
After replacing the ballvalve with a
solenoid valve

Apparent Losses and Roof Tanks
Malta findings D Class meter under registration – roof tanks
• New class D meters installed before and after roof tank
• 6%-9% less volume recorded on the inlet meter due to low flows from ball
valves
• Changed control to solenoid system
• Inlet meter registered 5%-9 %more
• Potential for E1.5 million savings 3.75Lt/Hr 7.5Lt/Hr 1m3/Hr 2m3/Hr
Class D
(Qn=1.0m3/Hr) Meter
Accuracy
Flow
5% under-recording
5% over-recording
2% over-recording
2% under-recording
3.75Lt/Hr 7.5Lt/Hr 1m3/Hr 2m3/Hr
Class D
(Qn=1.0m3/Hr) Meter
Accuracy
Flow
5% under-recording
5% over-recording
2% over-recording
2% under-recording
Class D
(Qn=1.0m3/Hr) Meter
Accuracy
Flow
5% under-recording
5% over-recording
2% over-recording
2% under-recording
Class D
(Qn=1.0m3/Hr) Meter
Accuracy
Flow
5% under-recording
5% over-recording
2% over-recording
2% under-recording
Ball or
Float
Valve
Flow recorded by meter, at a flow
above starting flow
Flow not recorded by meter, at a
flow below starting flow
Water being consumed within
household
Flow
(Lt/Hour)
Time (Minutes)10 20 30 400
10
20
30
above starting flow
household
Flow
(Lt/Hour)
10
20
30
Ball or
Float
Valve
Ball or
Float
Valve
above starting flow
household
Flow
(Lt/Hour)
10
20
30
above starting flow
household
Flow
(Lt/Hour)
10
20
30

Apparent losses reduction
• How to reduce the apparent Losses?
• What is the economic level of apparent losses
that can be accepted for a water utility?

Potentially Recoverable
Apparent Losses
Pipe Materials
Management:
selection,
installation,
maintenance,
renewal,
replacement
Data Analysis
Error Between
Archived Data
and data Used
(Billing/water
Balance)
Speed and
quality
of repairs
Data Transfer Error
Between Meters and
archive; poor
customer
accountability
ELAL - Economic Level of
Apparent Losses
Unavoidable Annual
Apparent Losses
Active
Leakage
Control
Unauthorised
Consumption
Current Annual
Apparent Losses
Customer Meter
inaccuracy
The Pillars approach to the control of
Apparent Losses

METER REPLACEMENT STRATEGY
WATER UTILITIES NEED TO ASSESS HOW FREQUENTLY METERS
ARE BEING REPLACED
SUPPLIED WATER VOLUMES ARE TOTALLY
MEASURED AND ACCOUNTED FOR
WATER METERS MORE EFFICENT AND RELIABLE

REPLACEMENT INDICATOR
20
In the paper
C. M. Fontanazza, G. Freni, G.La Loggia, V. Notaro & V.Puleo “A composite
indicator for water metre replacement in an urban distribution network”, Urban
Water Journal, (2012) DOI:10.1080/1573062X.2012.690434"
the authors propose a performance-based tool suggesting a consistent
replacement strategy of the meter installed in a water supply network to the
reduction of apparent losses
able to analyse the performance of the meters during their
operative life taking into account the different factors affecting
the meters accuracy
DEFINITION OF A COMPOSITE INDICATORS
“REPLACEMENT INDICATOR, RI= f(flow,pressure,meter age)

Cost benefit Analysis
1. Estimation of cost to reduce each component of apparent
losses
– Replacing customer meters
– Updating of the billing system (new software, better audit etc.)
– Training personnel on reading and managing data
– AMR (Automatic Meter Reading)
– UFR (Unmeasured Flow Reducer)
2. Evaluation of benefit (reduction of apparent losses)
3. Choose the solution with the best cost-benefit ratio and low
pay-back period

ELAL – Economic Level of Apparent Losses
Lmin
Lmin = Economic Level of Apparent Losses
From AWWA Manual M 36

Problems in ELAL calculation
ELAL is difficult to calculate.
– Different curves for each component,
– Necessary to consider meter accuracy at different
meter lives (time consuming)
IWA Water Loss Task Force is developing a
simplified method of obtaining ELAL

Actions to reduce Apparent Losses
• Audit the customer meter reading and billing process
• Perform annual meter accuracy test on a small sample (50 meters)
• Installation of new meters to measure public water uses that are authorized
but un-metered;
• Verification of large consumers’ meters;
• Check billing database to report broken meters (reading equal to zero)
• Conduct customer connection survey in selected area where apparent
losses are higher in order to identify illegal connections
• Cross check customers of the water services with the customers of the
electricity service.
• Audit of domestic and commercial customers connections and verify if they
correspond to the information on the customers’ database

The Bottom-up Validation of the
Water Audit
Step 1: Analyze the workings of the customer billing system to identify
deficiencies in the water consumption data handling process (Meter Reading,
Billing, Payment Processing, Collection)
Step 2: Sample Customer Survey, including number of meters by meter size,
customer type, and consumption ranges (check anomalies in flow size).
Step 3: Perform meter accuracy testing for a variety of sample meter
installations to understand the functional status of the meter population.
Step 4: Assess a sample of customer accounts or locations for unauthorized
consumption potential.

AMR (Automatic Meter Reading)
“Fixed System”: It is the more complex system as it is fully automatic.
– Short transmission intervals without any manual intervention
– Data logging for the more advanced versions
– Advanced statistic of customers consumption
“drive-by system”: data are collected via a receiver passing near the
transmitting units
– Low possibility of data logging
– High transmission interval
– Useful only for billing porpoises

AMR Integration with other
devices
Bulk Meter
Noise Loggers
Users’ Meters
AMR
Repeater

Benefits from AMR
• Readily available users’ consumption at the more convenient time step
(monthly, weekly etc.)
• Full integration of AMR technology with the billing system for quick invoice
and reference
• Reducing of manpower: no need to read manually water consumption and
to transfer data to the billing database
• Alarming system to know quickly any anomaly like non-operating meters or
under reading
• Fully automatic process from reading of consumption to issue of invoice

AMR – Hourly Pattern Domestic consumptions
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 2 4 6 8 10 12 14 16 18 20 22 24
Domestic Consumption Pattern

AMR possible problems
• Sometimes necessary to install many repeaters to improve
transmission reliability
• AMR repeaters and concentrators mount on light pole or on the
building roof, authorization needed
• Maintenance needed
• Failure data transmission (less then 100% transmission rate),
necessary to interpolate past user consumption
• High cost

Evaluation of Illegal Connections (1)
• Estimate Real Losses (Minimum Night Flow Analysis)
• Evaluate customer meters inaccuracy (sample test,
average weighted error)
• Compile IWA water balance and calculate Illegal
Consumption for difference

1 1.1 1.1.1 1.1.1.1 A.
Authorised Consumption Billed Authorised Consumption Revenue Water
12687
1.1.1.2
100000
1.1.2 1.1.2.1 B.
Unbilled Authorised Non- Revenue Water (NRW)
Consumption
1000
1.1.2.2
650
1.2 1.2.1 1.2.1.1
150000 Water Losses Apparent Losses
300
1.2.1.2
680
1.2.2 1.2.2.1
Real Losses
33983
1.2.2.2
200
1.2.2.3
500
112687
Leakage and Overflows at Utility’s Storage Tanks
TILDE Simplified Water Balance using the IWA methodology (all figures in m3 / day)
1650
980
34683
Unbilled Metered Consumption
Unbilled Un-metered Consumption
35663
37313
114337
Leakage on Service Connections
112687
Distribution Input Volume Billed Metered Consumption
Billed Un-metered Consumption
Unauthorised Consumption
Customer Metering Inaccuracies
Leakage on Transmission and/or Distribution Mains

This test should be done if illegal connections are
suspected in a specific area
– Test area (DMA/Sub DMA isolation)
– Verify that no leak exist with acoustic equipment
– Close all connections
– Check the inlet flow meter for any positive flow

Reality: difficult to obtain leakage ZERO
Solution: after closing all connections check flow
at the inlet.
– If flow is constant during time (2-3 hours) it’s
leakage
– If flow is floating there is illegal use
– If flow is ZERO: no leaks no illegal use

AQUAKNIGHT Objectives
1. Reduce the water losses of distribution systems and
rationalise demand in line with the environmental policies of
all MED States.
2. Enhance the capacity of Mediterranean water operators in
Non Revenue Water management by means of Active Leakage
Control and improved water metering
3. Validate / Develop best practices to manage real and
apparent water losses in the Mediterranean context

Evaluation of Commercial Losses
1. Installation and testing of an AMR system
2. Evaluation of consumption patterns and meters under-registration
3. Evaluation of benefits of meters replacement and UFR

• Creation of a small subdistrict with less
than 100 users
• Installation of an accurate inlet flow
meter and comparison with accumulated
customer meters readings
• Installation of UFRs
• Replacement of customers old meters
with new meters incorporating AMR
• Bench testing of old meters at UNIPA’s
laboratories

Ball valve
D
h, V
Private
tank
UFR +Flow meter
ASSESSMENT OF IMPACTS OF UFR ON METER UNDER-READING

UNIPA’s laboratory test bench
The accuracy of the selected meters was tested by the UNIPA’s laboratory test bench
The test bench is a weight calibration device compliant with the ISO 4064:2005 standard
UNIPA
• a water supply system (mains, 1 unpressurised
tank, 2 pumps);
• a test section in which the meter is placed;
• 4 flow meters to establish the approximate
flow rates at which the meter is tested;
• 2 pneumatic and automatic gate valves;
• 2 pressure gauges to measure the pressure
upstream and downstream the tested meter;
• 1 vacuum gauge;
• 2 calibrated tanks, each placed on a precision
electronic balance;
• 1 temperature sensor
• 1 a control panel

UNIPA’s laboratory test bench
Laboratory experiments were carried out in UNIPA laboratory in order:
• to estimate metering error curves for different flow meters classes and ages
• to find a direct link between meter age, network pressure and the apparent losses
caused by the incapability of the meter to accurately measure the volume passing
through it at low flow rates
Class C; Q3 = 2.5 m3/h; DN 20 mm Class C; Q3 = 2.5 m3/h; DN 20 mm
-6
-4
-2
0
2
4
6
0.001 0.01 0.1 1 10
Errore[%]
Q [m3/h]
-6
-4
-2
0
2
4
6
0.001 0.01 0.1 1 10
Errore[%]
Q [m3/h]
Class C; Q3 = 1.5 m3/h; DN 13 mm
-6
-4
-2
0
2
4
6
0.001 0.01 0.1 1 10
Errore[%]
Q [m3/h]

Water meters selected in the
Genoa DMA
UNIPA
OLD METERs - Multijet - Class B and C
NEW AMR METER – Multijet – R160

Test bench results: Genoa old water meter
Test pressure: 2 bar
UNIPA
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
Water meter 99-455018-DN15mm-Class C
Brand Schiumberger/Schol
Diameter DN15 (1/2'') Nr. Point Flowrate Error Flowrate Error Flowrate Error Flowrate Error
Class C [m3/h] [%] [m3/h] [%] [m3/h] [%] [m3/h] [%]
Serial number 99-455018 1 Q1 0.016 -26.32 0.016 -24.98 0.015 -24.97 0.016 -25.42
Age 14 2 0.5(Q1+Q2) 0.019 -12.93 0.019 -12.16 0.020 -5.10 0.019 -10.06
TEST ISO 4064:2005 3 Q2 0.024 -10.96 0.024 -9.85 0.024 -10.97 0.024 -10.59
Q1 0.015 4 0.33(Q2+Q3) 0.528 3.80 0.515 3.91 0.516 3.59 0.520 3.77
Q2 0.0225 5 0.67(Q2+Q3) 1.054 3.00 1.055 2.65 1.065 3.02 1.058 2.89
Q3 1.5 6 Q3 1.474 2.44 1.449 2.57 1.436 2.44 1.453 2.48
Q4 3 7 Q4 2.959 1.80 2.965 3.91 2.975 0.14 2.966 1.95
AverageTest point TEST 1 Test 2 Test 3
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
Test 1 Test 2 Test 3
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
Average curve
Each meter was tested three times and finally the average error curve was evaluated

Diameter DN15 (1/2'') Nr. Point Flowrate Error Flowrate Error Flowrate Error Flowrate Error
Class R160 [m3/h] [%] [m3/h] [%] [m3/h] [%] [m3/h] [%]
Serial number 1330046901 1 Q1 0.015 2.65 0.015 2.65 0.015 3.43 0.015 2.91
Age 0 2 0.5(Q1+Q2) 0.019 4.11 0.019 1.02 0.019 6.47 0.019 3.87
TEST ISO 4064:2005 3 Q2 0.024 7.51 0.024 2.59 0.024 3.18 0.024 4.43
Q1 [m3/h] 0.015625 4 0.33(Q2+Q3) 0.511 1.84 0.538 1.79 0.549 1.59 0.533 1.74
Q2 [m3/h] 0.025 5 0.67(Q2+Q3) 1.028 0.91 1.040 1.29 1.043 1.14 1.037 1.11
Q3 [m3/h] 2.5 6 Q3 1.377 1.20 1.447 1.01 1.439 1.61 1.421 1.27
Q4 [m3/h] 3.125 7 Q4 2.982 0.49 2.887 0.50 2.885 0.73 2.918 0.57
Test point TEST 1 Test 2 Test 3 Average
Test bench results: Genoa new AMR
UNIPA
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
AMR-Water meter 1330046901-DN15mm
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
Test 1 Test 2 Test 3
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
Average curve

Test bench results: Genoa water meters
Test bench results were analysed classifying the
meters in 5 age classes
CLASS 0 = new meters
CLASS 1 = meter age ranging between 1 – 5 years
CLASS 4 = meter age major than 15 years
UNIPA

Test bench results: Genoa water meters
UNIPA
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
CLASS 1 - Age (0-5 years)
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
CLASS 2 - Meter age [5-10 years)
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
CLASS 3 - Meter Age [10-15 years)
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
CLASS 4 - Meter Age > 15 years
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
0.001 0.01 0.1 1 10
Error[%]
Q [m3/h]
CLASS 0 - New AMR

Customer Night Use Estimate
Unipa worked in the determination of customer demand patterns
and legitimate night use by customers
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 2 4 6 8 10 12 14 16 18 20 22 24
Domestic Consumption Pattern

2.2. unipa vincenza notaro - management of apparent losses

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2.2. unipa vincenza notaro - management of apparent losses