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Measures and management challenges

Due to the successful implementation of the Urban Waste Water Treatment Directive (UWWTD), point source pollution pressure from urban waste water has significantly decreased. This is the result of the improved rate of population connected to sewage systems, but also the implementation of second (biodegradation) and third (nutrient removal) treatment levels all over Europe ([5]).

Measures to further reduce point source pollution from urban waste water but also industry include e.g. construction and adaptation, expansion, optimization of existing treatment plants, connection of households to sewer systems or consolidation and closure of non-effective treatment plants.

Improved efforts to retain chemicals in waste water treatment plants should go hand in hand with clear efforts to reduce them at source. Such measures can range from raising consumer awareness, to encouraging industries to adjust the composition of their products, to, over the longer term, fundamentally reviewing our use of chemicals and product design.

One example of source-based measures is the ban of phosphates in consumer detergents to avoid eutrophication in surface waters. The remaining allowed use of phosphates was legally fixed in Regulation 648/2004/EC (EU 2004). The European Parliament proposed a ban of the use of phosphates in consumer laundry detergents as of 30 June 2013 with similar restrictions to automatic dishwasher detergents for consumers as of 1 January 2017 ([6]).  

Furthermore, measures can be assigned to stricter requirements like lower targets for concentrations of specific pollutants in the discharged waste water by the responsible authority. This has been applied to protect drinking water resources of Lake Constance, the biggest lake in Germany. All treatment plants at the tributaries of the lake reduced markedly their phosphorous concentrations in the waste water discharge. Till today, Lake Constance is at good ecological status with drinking water quality (International Commission for water protection of Lake Constance (IGKB), 2014).

Even though considerable success has been achieved to reduce the discharge of pollutants from point sources, more emphasis is needed to protect water quality and human health. Despite varying conditions such as the density of population in European countries, or economic background, treatment has to be further improved in eastern parts of Europe in particular. A lower storm overflow is necessary with the help of nature-based solutions. To increase treatment, the implementation of the fourth treatment level is in progress. This level consists of innovative treatment techniques (e.g. oxidation with ozone, activated carbon filtration, membrane filtration) (UBA, 2014, EEA, 2019c). For example, by 2040, 100 of the 700 wastewater treatment plants in Switzerland will be equipped with a fourth purification level after decision in a plebiscite ([7]). The investment requirement of CHF 1.2 billion will be financed through a nationwide wastewater tax, which is a maximum of CHF 9 per inhabitant and year ([8]).

Furthermore, increasing energy costs, the reuse of high quality waste water and recycling of raw materials to circular economy as well as the consideration of climate change will be challenging tasks for the future (EEA, 2019).

([5]) Source: Source: https://www.eea.europa.eu/data-and-maps/daviz/changes-in-wastewater-treatment-in-8

([6]) Source: https://ec.europa.eu/commission/presscorner/detail/en/IP_11_1542

([7]) Source: https://www.vdi-nachrichten.com/technik/die-vierte-reinigungsstufe/

([8]) Source: https://www.vdi-nachrichten.com/technik/die-vierte-reinigungsstufe/