Water supply in Hanau is secured even in dry seasons

A few days ago it was cooler and it rained a bit. But that didn’t do much. It’s still too dry. Way too dry. And the next heat wave is just picking up speed. In many places there are warnings about falling groundwater levels. In the Taunus, for example, citizens are officially called upon to save water.

Hanau – And in the entire Main-Kinzig district, water has not been allowed to be taken from streams or rivers for some time.

So will drinking water soon be scarce in Hanau too? dr Dirk Drescher gives the all-clear. “The drought isn’t a problem for us,” says the head of operations at Stadtwerke Hanau. Even if the levels are a little lower than usual, there is no threat of a bottleneck. Because: Hanau is relatively independent when it comes to supply.

You pump around 75 percent of the water yourself, explains Drescher during a visit to our newspaper in Wasserwerk II on Leipziger Strasse. Because of their location on the other side of the Main, Steinheim and Klein-Auheim have always been supplied by the Offenbach City and District Water Supply Association. Both parts of the city account for around 20 percent of the total demand. “There is no line through the Main,” explains Drescher. According to Drescher, another small proportion is obtained from the Kinzig water association. This supplies the northern Main city area.

The municipal utilities get their water through 79 shallow and 15 deep wells. The former are about ten meters deep, the latter about 150 meters. If the groundwater is too low at a pumping point, another well steps in. Saving is therefore basically not necessary in Hanau, at least not because of the supply. However, it depends: If you wash your car on a sealed, for example asphalted surface, the water does not seep away. “It ends up in the sewers, then in the Main and finally in the North Sea. It will be a while before it gets back here,” explains the division manager.

The groundwater is pumped from the wells with powerful pumps into the city’s six waterworks – with locations from Mittelbuchen via Wilhelmsbad to the Bruchwiesen in Großauheim. Once there, it is first ventilated. “Since the water is initially low in oxygen, it has to be supplied,” explains Drescher. Incidentally, the quality of the water varies from pumping point to pumping point. “The hardest water comes out of the ground in the Hohe Tanne, it’s softest in the city center,” he says. The calcium, sodium and magnesium content also differs.

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The later drinking water then runs through several huge filter systems that work on a bacterial and mechanical basis. Among other things, iron and manganese are released, but also carbon dioxide, which is dissolved in deep water. The substances collect in the respective filters, which have to be cleaned from time to time. Jochen Häfner has this and many other things in mind at Wasserwerk II. From the control center he can not only look at the pumps. Several displays show him whether everything is in order with the water and his way through the plant. Häfner is the main plant engineer responsible for waterworks II and VI (Bruchwiesen). He is one of eight employees of the municipal utility who take care of the water in the Brothers Grimm City.

After the water – well over five million cubic meters per year – has been filtered, it flows to the households via a connection system that is around 360 kilometers long. A portion is always kept available in one of the drinking water reservoirs. With a capacity of 10,000 cubic meters, the location on Leipziger Strasse is home to the largest storage facility in the city. To visit it, we even have to get in the car. It’s on the other side of the train tracks. First it goes down many steps, then under the attic, finally up a long spiral staircase again. Then we got to the top. Water as far as the eye can see. “The good Hanau drop. This can cover half of the drinking water requirement for the whole of Hanau for one day,” reveals Drescher when looking down on the gigantic round pool, which is quite similar to a swimming pool. Except for the temperature, because the water comes out of the ground at only eight to ten degrees. This cools the entire building down to almost refrigerator temperature – not unpleasant given the hot temperatures.

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There is a constant splashing all around you, as the coveted raw material is constantly being circulated. There shouldn’t be a corner where the water is standing, that’s the rule, explains Drescher. Some operators even placed small rubber ducks on the surface so that this could be observed.

The reservoir is not the only thing to see on the extensive grounds of the waterworks. An old drinking water basin has been left to nature and created as a pond. Lots of plants grow there, even fish swim in it. “It’s been very well received. Do you also see the crocodile?” asks system engineer Häfner and laughs. In fact, a deceptively real reptile swims in the middle of the pool. Häfner placed it there. He likes the place and likes to spend his lunch break there. The area on Leipziger Strasse also has something of a recreational feel to it. Lots of green, lots of peace and quiet – the animals also appreciate that, as Drescher and Häfner report.

While both make it clear on our tour that there is no water shortage in Hanau, the municipal utilities are confronted with other problems. “Maintaining quality is the challenge of the future,” says Dirk Drescher. Above all, perfluorinated and polyfluorinated chemicals, so-called PFAS, cause trouble. They are contained in impregnation and pesticides, for example.

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“It becomes problematic when we exceed certain limit values,” says Drescher. Then the filters clogged up faster and more frequent replacement would be necessary. “Instead of an exchange every one to two years, we’re talking about once a month. And such a load costs 30,000 euros,” says the Head of Operations. The inevitable consequence: higher water prices.

By Christian Dauber

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