Water reuse: A sustainable solution to the global water crisis

Donau Chemie Water Technology
Global water scarcity and clean drinking water challenges are more pressing today than ever before. In this context, water reuse is gaining importance as a sustainable solution. This article highlights the current water problems, especially in Europe, and shows how water reuse can help alleviate water stress and use water resources more efficiently.

The global water crisis in 2023: Health and economic impacts

According to the WHO's "World Health Statistics 2023", approximately one quarter of the world's population does not have access to clean drinking water. It is assumed that the lack of access to clean water and washing facilities is the cause of 2.5 % of all deaths worldwide. However, lack of water not only has a negative impact on our health, but also impacts agriculture, the economy and the environment. According to the study "Water Resources Across Europe", areas larger than Austria have been affected by droughts in recent years. Nor is it assumed that the stress on our water resources will decrease.

Water resources in Austria: Drinking water quality and challenges

In Austria, we are in the fortunate position of being able to obtain almost all of our drinking water from groundwater and spring water. One exception is Vienna, where Danube bank filtrate can also be provided by the Lobau waterworks in case of extraordinary demand. Drinking water usually reaches households in its natural state. However, in the case of particularly long transport routes or long residence times of the water in the supply network, traces of chlorine are added to ensure that it is still in perfect hygienic condition when consumed.
However, this does not always have to remain the case, for example: the study "Wasser Schatz Österreich" (Water Treasure Austria) comes to the conclusion that under certain unfavorable circumstances – locally limited – the demand for water would exceed the regenerative capacity of our groundwater.

Water sources in Europe: A look at drinking water production

Certainly, drinking water does not necessarily have to be provided from groundwater or spring water. For example, the Lake Constance water supply company treats water from Lake Constance for around four million people in the greater Stuttgart area. In the EU, only about 65 % of drinking water comes from groundwater. The rest comes mainly from surface water, which is taken, for example, via river bank filtration.

Clear water fractions in rivers: The impact on drinking water supplies

The effort required to treat surface water can vary greatly, depending on the quality of the water body. The study "Dynamics of clear water fractions in surface waters and possible challenges for drinking water production in Germany" shows that under low water conditions, the majority of German rivers obtain more than 10 % of their water from wastewater treatment plants. In some cases, more than half of the discharged water already comes from a wastewater treatment plant.
In the study in question, the concentration of selected trace substances was measured. Because these trace substances, such as the active ingredient carbamazepine, can basically only come from domestic wastewater, the concentration can be used to calculate the proportion of wastewater treatment plant effluent in the river. Due to the high quality of wastewater treatment, this need not be a problem yet, but it may well make the treatment of drinking water more costly.
Considerably more effort is required if the rivers flow through regions where the connection rate of the population to modern wastewater treatment plants is sometimes less than 50 % and therefore a considerable proportion of the water still enters the rivers untreated.

Water reuse as a solution: The EU Safe Irrigation Directive

Population concentration in metropolitan areas, climatic changes, and other causes can increase the "stress" on individual water resources and require consideration of how to use water most effectively in the future.
Water reuse can be part of the solution. The EU directive on water reuse refers to the reuse of clarified water in agricultural irrigation. Clarified water is the water that leaves a treatment plant after being purified (effluent). The directive prescribes the treatment and safety measures that must be taken to ensure the safe use of water for crop irrigation. For this purpose, stricter quality requirements are set than for surface water.
Considering the proportion of clarified water in some surface waters during a dry period, it can be assumed that the direct use of clarified water is less hazardous due to the strict testing. For the Federal Environment Agency in Germany, however, the regulation does not yet go far enough, for example with regard to trace substances.
As Donau Chemie AG, we can make our contribution to water reuse by providing the necessary operating resources. Our precipitants are indispensable for the operation of most wastewater treatment plants, for hygienisation we offer a range of disinfectants, and for the removal of trace substances we provide solutions with activated carbon that are unsurpassed in their range and robustness by any established process. 

Sustainable water use: Water reuse in different sectors

In somewhat broader terms, water reuse is already being successfully implemented in industries other than agriculture: Without water reuse, it would take about 100 liters of water to produce one kilogram of paper. Modern recycling reduces this to 10 liters, in some cases even to 2 liters. In Austria alone, more than 400 million cubic meters of water can be saved each year in this way. This is about half of the water consumed in Austrian households.
Since good quality paper can only be produced with pure water, high-quality purification is necessary. For this purpose, Donau Chemie's portfolio includes water technology products. Thus, the use of one liter of Donau PAC papyro can recycle more than 7,000 liters of water.
Mining and tunneling operations can also generate large quantities of wastewater which, after treatment, can either be recycled or returned to natural waters. In the treatment process, water technology products significantly facilitate the separation of mineral substances and do so without the use of organic additives. In this way, not only is the water purified, but a pure mineral residue remains. The soil-like composition also significantly facilitates the landfilling of the separated material.

Donau Chemie Water Technology: Innovative solutions for water reuse

For years, Donau Chemie AG's water technology has been a reliable partner for Europe's water treatment companies. In order to continue to meet the growing demands, we are constantly developing ourselves and our products. In this way, we make our contribution to ensuring that people in Europe continue to have access to clean water. In this sense, the following years will not only be challenging, but certainly also very interesting.
Donau Chemie Water Technology


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