Engineer Stadtwerke Gleisdorf
What is the water supply like in Gleisdorf? Does the issue of "non-revenue water" also pose a challenge in East Styria? If so, how are water losses detected? We wanted an answer to this and much more from Mirjam Mautner, an engineer at the Stadtwerke Gleisdorf (public utilities). In an in-depth interview, she gives us an intriguing insight into her work and tells us why there are no more illegal water withdrawals in Gleisdorf.
How long have the Stadtwerke Gleisdorf been in existence?
The Stadtwerke Gleisdorf have been around since 2000. Before that, the supply of water and district heating was the responsibility of the municipality or the Feistritzwerke, the electricity network operators in the region. A period of restructuring in 2000 led to the founding of the Stadtwerke Gleisdorf, which are owned exclusively by the municipality. In 2005, we took over another large area of business, namely waste management which meant we were now responsible for the entire waste disposal in the town.
How many residents do you supply with water?
Gleisdorf used to have about 6,000 inhabitants. In 2015, a municipal merger took place which saw the incorporation of four additional municipalities. As a result of this merger, the number of residents who had to be supplied with water suddenly shot up to 10,500. This also affected waste disposal.
Where does the water supply for Gleisdorf come from?
We produce about 25 percent of the water needed ourselves from wells and springs. The rest is purchased from the water reservoirs located further afield in Weiz or Graz and from the Hochschwab mountains, and then transported via pipelines operated by the TLO (East Styria transport pipeline) and WOR associations. There are large water reservoirs in the Weiz mountains, the Graz basin and on the Hochschwab mountain. To supply water, we have 218 km of water pipelines, 5 drinking water reservoirs, 6 wells and 6 springs, which we operate ourselves.
How do you locate leaks in service connections?
We detect leaks by recording the water consumption of our networks at night between 1 a.m. and 4 a.m. To do this, we have accurate water meters installed at our major support points, such as at the elevated tanks or pumping stations. These meters and installations are connected to a telecontrol system, which means that every morning we can refer to the night log to see how much water was consumed during this period.
This is the time when water consumption is at its lowest, and so if there is a sudden jump in consumption or a slow increase, it's a sign of a burst pipe. If this does happen, we immediately set about searching for the leak. By the way, we always completely renew the service connections. This means that we don't just replace the damaged (pipe) part, but the entire connection, including the meter unit and so on.
How big does the leakage have to be for any deviations in the water flow to be detected?
Very small indeed. In the city centre we use an additional 200 acoustic data loggers to monitor the piping network. We can pinpoint a 0.1 litre/second pipe burst. Often the smallest pipe bursts, which are just a spray on the outside, are the loudest when located. A larger pipe burst can be quickly localised using the night log and the acoustic data loggers.
We also have warning systems which alert us via SMS in the event of a violent rupture, i.e. a massive pipe burst. This SMS is also sent to our on-call service, which is available 24 hours a day, 7 days a week.
How do you repair leakages in service connections?
As I mentioned earlier, we're pursuing a new strategy here. This means that when a road is repaired or a pipe bursts, we renew the entire pipework, including the service connections - absolutely everything, irrespective of the age of the fittings and pipes. Not only are the water pipes replaced, but also the electricity lines and the optical fibre network. If it is appropriate for the area, district heating will also be extended.
This involves closing the road for up to three quarters of a year, but then everything is really brand new. Only after these construction works will the road be asphalted and renovated not only from "above" but also from "below".
What products do you use for leaks in the water mains?
If it is not possible to dig up the entire road (as is the case when replacing a service connection or restoring a road), we fix it using pipe repair clamps. If there are longitudinal cracks, for example, we have to cut two metres out of the pipe and install Synoflex or System 2000 fittings, depending on the pipe material.
What do you see as the main difference between repairs today and about 15 years ago?
In the past, repairs were minimalistic. If an iron pipe broke in a service connection 10 - 15 years ago, a small clamp was placed on it. If the same pipe burst again two years later at an adjacent point, another clamp was mounted. Eventually there were as many as five clamps on a service connection pipe. All in all, this approach was costly. Now this money is being spent to replace everything in one go.
This approach is challenging because we have to react at short notice, but ultimately it is more effective.
Is climate change having an impact on drinking water supplies?
Definitely in terms of water as a resource. In this case, for example, we are seeing a higher demand for watering gardens. We sell around 1 million m³ of water to our customers every year. Of this, 50 per cent is supplied to industry and community facilities such as swimming pools and football stadiums. The other 50 per cent we sell to households, and here we are noticing a higher demand, especially in the summer months.
We used to have one or two daily peaks when 3,000-3,500 m³ of water were needed. Today, we often have 10 times as many daily peaks, and these long dry spells are becoming more frequent. We are also finding that pools, especially small above-ground pools, are mushrooming.
Is illegal tapping an issue for the Stadtwerke Gleisdorf?
No. We are in fact staunch users of S.CAP, the smart remote monitoring system for hydrants. About 1.5 - 2 years ago, we retrofitted all of our hydrants, more than 320 in total, with S.CAP.
What do you do to prevent hydrant leakage?
We have our hydrants checked every five years by Hawle Service GmbH. Thanks to this regular maintenance, we have a good idea of the condition our hydrants are in. In addition, our hydrants are only activated by the fire brigade and our trained personnel in the event of a fire.
This means that no outside personnel or private individuals are permitted to use the hydrants for purposes such as filling the pool. To do this, we send a member of our trained staff to open the hydrant and close it again properly. Then, every time the hydrant is re-closed, we use a listening device to check whether it is really shut and leak-proof. We have been keeping a very close eye on this for several years.
Why do you trust in Hawle?
Because Hawle products have enjoyed a consistent quality for decades and we can rely on them. The entire approach, from service to product, makes perfect sense. We have a very good basis for communication and together we always find a solution. Hawle has never disappointed us, which explains why we are very satisfied customers.
Thank you very much Ms Mautner for your time and for giving us this fascinating insight into the activities of the Stadtwerke Gleisdorf.
Hawle visits Stadtwerke Gleisdorf (public utilities)
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