Much has been written about the unacceptably high non- revenue water losses suffered by most municipalities and it is common knowledge that there are few water supply authorities that can claim a water loss of less than 30% of their purified water input. It is being claimed that one of the primary factors for this incredible water loss is aging reticulation infrastructure. Two primary components of a water reticulation infrastructure are pipework and meters. A number of municipalities have recognised the importance of accurate metering, both from the view point of increased revenue recovery from billing and, perhaps even more importantly, with respect to identifying where the water losses are occurring.It is a fact that the accuracy of volumetric type mechanical water meters used mainly for domestic metering deteriorates over time. This deterioration results in ever-increasing volumes of water not being measured. Some municipalities have identified this and are actively embarking on meter replacement programs. In Germany for example, the legal requirement for the replacement of mechanical domestic meters is six years. The South African Water Meter Manufacturers’ Association has proposed legislation setting the target at every 10 years. The reality at present is that the vast majority of meters in this country have been in service for between 10-15 years. Besides some tweaking, the fundamental components and basic principle of commonly used volumetric domestic meters have not changed in over 30 years. The question needs to be asked as to the effectiveness of meter replacement programs given the relatively short accurate lifespan of the replacement meters.A project undertaken by one of the largest and most proactive municipalities in South Africa revealed an average improvement of nine percent in billing, after replacing the older mechanical meter technologies with new and improved technologies. These findings indicate that staying with meters where technologies have remained basically static for decades is a costly exercise.At the recent international Water Berlin Exhibition, it was interesting to note that all of the major meter manufacturers were exhibiting the next generation of “smart meters” which, in most cases, extended beyond the smart meters to a so-called “smart grid” capable of assimilating and transferring data on both water and electricity meters directly to a central database in near real time.The new generation of smart meters incorporates two basic features: a measuring technology having no moving parts and an electronic RF interface allowing for remote reading of the meters. The fact that smart meters are not subject to wear means that their accurate service life can extend to 10 years and in the case of the new SensusiPerl, a guaranteed accurate service life of 15 years.
The downside of the new technology is the initial capital outlay which could be three or more times that of conventional mechanical meters. Although the electronic meter is more expensive, the cost of installation and ownership is greatly reduced. These meters do not require a protective housing, nor the cleaning of strainer blockages or replacement due to stoppages. They can be installed off the verge within the customer’s property, resulting in less tampering and vandalism. Additionally, meter reading errors are eliminated as these meters are read remotely. Despite incontrovertible evidence reflecting a staggering drop in water loss coupled with a substantial increase in revenue it requires a “leap of faith” to make the change to smarter metering technology.
The interim solution is to opt for a newer generation volumetric meter which has been “smart meter enabled”. Typically this entails a volumetric meter employing the very latest construction materials which are lighter, more sensitive and with better wear resistance, but more importantly, can be fitted with an “intelligent” RF module. The module replaces the old and unreliable reed switch, which is not suitable for billing purposes, with an accurate, high resolution inductive interface. The module incorporates the intelligence normally associated with a true smart meter such as meter serial number, total recorded volume, forward/reverse flow, leak detection etc. This information is transmitted at frequent intervals to the central database. Besides ensuring accurate billing, it allows water supply authorities to warn consumers of possible leaks and excessive consumption in near real time.