14 aug 2003Metering Brazil’031 Metering, Billing, CRM/CIS Americas 2003 Medição, Faturamento, CRM/CIS Brasil 2003 12-14 August 2003 Crowne Plaza Hotel,

14 aug 2003 Metering Brazil’03 1

Metering, Billing, CRM/CIS Americas 2003 Medição, Faturamento, CRM/CIS Brasil 2003

12-14 August 2003Crowne Plaza Hotel, Sao Paulo, Brazil

Indirect sewage billing, by water consumption balance and

telemetry

Jorge Gomez SanchezEngineering & Systems

Invensys Metering do Brasil


Sewage billing In Brazil, Sanitary companies are usually

responsible for water distribution and sewage collection services

In water supply the water consumption is billed by the volume read on watermeters

The sewage is much more difficult to be billed : There is no characterised “product” to base the bill It is not easy to measure the discharged volume and

flowrate It is not easy establish the “cost” of the discharged sewage

Sewage billing is a potencial source of controversy with consumers


Sewage billing

Ways to refer and establish the sewage bill :

Charge a fixed fee, according to consumer categories (industrial, residential, commercial)

Industrial billing based in categories related to parameters, like size, kind of activity and product, level of production

Sewage bill based only on water consumption

Sewage bill based on the water consumption together to other parameters related to pollution burden

Bill based on direct sewage measurement


Billing by fixed fee, based or not on external parameters

AdvantagesEasy billing and

controlDoes not rely on

meters and periodic reading

No inspection or checking is necessary

ProblemsInduce consumer complain

(even who does not produce sewage pays the same fee)

Does not identify consumers that overcharge the system

Does not incentive rationalisation of resources

The tariff is the same, independent on discharged sewage

Adequate to places with low variability


Sewage bill based only on water consuption

AdvantagesFair: Usually, the higher is

the water consumption, the higher is the sewage discharge

It is easier to express the sewage bill together with the water bill

Industries, that usually charges more the systems, pay higher tariff

Problemshigh water consumption not

always means high generation of sewage

The proportion water /sewage can be questioned

The consumer fells that the water is expensive: It tents to use alternatives suppliers.

Alternative water suppliers, like wells and rain collectors, have to be metered as well

It is a good alternative to charge fixed fees, but the consumer sometimes does not agree and goes to judicial claim


Bill is proportional to water consumption and other fixed

parameters Discounts can be applied in order to not

characterise that water consumption = sewage discharge

Multipliers can be applied according to the potential pollution burden examples :leather and food industries

multipliers and discount parameters can be established with water consumption and sewage surveys


Bill proportional to water consumption and fixed

parameters water comsumption parametrization Example: generic industry

Water inlet (watermeter)

Sewage outlet

factory

Office

Colling towers Steam generator

(boiler)Incorporated

water processesrefectory

Gardens (irrigation)


Bill proportional to water consumption and fixed

parametersAdvantages

Survey allows sewage characterization and makes the bill clear Identify the sewage generators: incentive to conservation actions Incentive sewage treatment by the consumerIdentify alternative water supply

problemsSurvey takes an instant

“picture” but the parameters can change

The consumer know when the survey is carried on na can change the activity

The sewage emission sometimes is not proportional to the water consumption

The survey is expensive and sometimes difficult

This method is been used by consumer demand, that hire consultant companies to do the surveys.


Direct measurement of sewage volume

Consists in install a meter in the sewage outlet of the consumer, in order to have the actual sewage volume that is discharged

Metering technologies that is been developed to measure sewage flowrate: Eletromagnetic Ultrasonic Open chanel Ultrasonic meters Weirs and flumes

Direct measurement of sewage volume is a frequent consumer demand


Direct measurement of sewage volume

AdvantagesDirect metering is clear for the consumer

Does not depends on water consumption surveys

Makes the water consumption and the sewage bill separate : The consumers really perceive the cost of the water and the sewage

ProblemsThere is no meters accepted by Brazilian metrological authority (INMETRO)

Sewage is not a well defined fluid: the measurement carries high uncertainty

It is not possible to be sure that the measured outlet is the only one.

The meters frequently over range when it rains (weirs overflow)

The consumer can concentrate the sewage (reduce the flow but not the pollution burden)

Direct measurement is not yet a reliable technology to be used as a reference for sewage billing


A proposal: simultaneous measurement of the consumed water that is not discharged

as sewage Instead of estimate the sewage by the

volume of consumed water, it is measured the amount of water that goes to processes that does not produce sewage : Water consumed in steam generation Water consumed in cooling tower (air conditioned) Water that is incorporated to the product (ex.

Beverage industries, concrete pre manufactured) The water bill is still based on the main

meter, but the sewage bill is based on the difference between the main meter and the process meters


Measuring the consumed water that does not generate sewage

Generic industry

m

m

m

Water inlet (watermeter)

Sewage outlet

factory

Office

Colling towers Steam generator

(boiler)

Incorporated water processes

refectory


m



Advantages The process is directly metered: There is not a fixed

relationship between sewage and consumed water There is no problem in previsions of season variation and

change in production Is the consumer that declares the process that consume

water but not discharge sewage: No judicial claims . Use of alternative sources can be verified on the balance Does not incentive sewer by passes or sewage

concentration Common water meters, certified by INMETRO, can be used Parameter surveys are not necessary The direct metering can be accessed by the consumer, that

knows the billing process, and can work to reduce it



Problems

Sometimes the meters have to be installed in places with not easy access for maintenance and reading

It is possible to get water from the process after the process meters

Eventual inconsistencies due to broken meters or variations in the activities can be noticed just after some readings (months)

It is still necessary to evaluate the consumer process to confirm the processes that consumes water but not discharge sewage



water use balance by on line reading and telemetry

Central metering (meter + telemetry) Sewage

outlet

Factory

Offices

Cooling towers Steam generator

(boiler)Incorporated water

process

refectory


m

m

m

m

CM

Parcial meter

Parcial meterParcial meter

Parcial meter

Comunication lines




All the meters are read simultaneously by telemetry

The reading of the partial meters is transmitted by wires or radio to a metering centre, that processes the readings and presents partial readings and the water consumption and sewage volume to be billed.

The metering centre can be directly connected to the utility by phone, mobile phone (GSM) radio on even optical cable (cable TV)




Examples:

Discount of water consumption on cooling towers Commercial offices with central air conditioning Shopping centres Industries with large heat exchanges

Companies that uses steam intensively Commercial and industrial consumers with

large loans and irrigated gardens


Added featuresWaste and pollution burden control

Other measurement devices can be connected on line to the system: Mesurement of sewage characteristics: temperature,

pressure, PH, conductivity, composition na even flow rate.

Other meters can be added to the system to be used as conservation feed back and management of the resources

The readings and evaluation can be available to the consumer by Internet


Detailing the system telemetry with communication on line

System architetureCommunication

media MBUSTelemetry

centre

Main meter

Partial meters

...

Net up to 250 meters, 4 km

wire

Pair of wiresM-Bus

A/D converter (Mbus)

Sewage meter (Weir)Pressure sensor

Other devices

-temperature

-PH

-composition



Metering centre



Metering centre



Metering centre


Evaluation software


Detailing the systemencoded meters and Intelligent pulser (HRI)


Conclusions The preset proposal of sewage billing based on water

consumption balance is closer to reality than other ways of billing, reduces consumer complains and the perception of high water price

Use of telemetry and evaluation software allows a better use of water, leak detection and identification of irregular water sources or even changes in consumer characteristics m

The system is available and is in use by SABESP The cost of the system can be partially supported by the

consumer, that has real interested in be billed by real sewage volume and not by the water consumption


Invensys: Technology for an intelligent world

Invensys Metering do BrasilJorge Gomez Sanchez - Engenharia & sistemas

Fabrício Mardegan

Robson Madsen - Vendas e aplicações

f. 0xx19 34666611

[email protected]

Documents

14 aug 2003Metering Brazil’031 Metering, Billing, CRM/CIS Americas 2003 Medição, Faturamento, CRM/CIS Brasil 2003 12-14 August 2003 Crowne Plaza Hotel,