Germany is the European country with the highest waste water reprocessing and recycling rate. More than 96 per cent of the waste water from private households or public facilities is discharged into nearby sewage treatment plants for processing.
In Germany more than five billion cubic metres of sewage water are generated each year by private households, industry and trade. But there is more: Approximately three billion cubic metres of rain water from paved surfaces and roads are also discharged into the sewage treatment plants with a considerable additional amount of infiltration water entering the sewer system through leaks.
In Germany it is not permitted to discharge untreated waste water into rivers and lakes, regardless of whether it originates from private households, trade or large-scale industry. The Federal Water Act (WHG) stipulates that pollutants contained in drainage water must be reduced in line with the best available technology.
According to Article 57, paragraph 1 of the Federal Water Act (WHG) discharges of waste water into water bodies is only permissible if the pollution load of the waste water is kept to the lowest level achievable by means of the best technology available. More detailed and specific requirements are set out in the Waste Water Ordinance (AbwV). An amended version of the Waste Water Ordinance of 1 January 2005 put the new into place provisions. For a total of 53 sectors appendices to the Ordinance now set uniform federal requirements for the discharge of waste water into water bodies. Waste water disposal of private households is a municipal responsibility.
According to the Waste Water Ordinance the interfaces between the environmental media waste, air, soil and water will be jointly assessed in the future. This provision makes sure that protective measures in the water sector will not go be the detriment of the air, waste and soil sectors. The IPPC Directive (integrated pollution prevention and control) established the best available technology standard in all environmental laws as a uniform basis for integrated assessments. The Waste Water Ordinance will therefore align its requirements for waste water discharges more strongly with the best available technology required across all environmental media. For waste water this implies an assessment of the entire sewage chain (input material, preventive measures, sewage system, sewage treatment facility) and the interface to other environmental media.
More than 96 per cent of the German population is connected to the public sewage system. Waste water from private households is collected in the public sewage system covering 540,723 kilometers of sewers and discharged into just under 10,000 waste water treatment facilities. 10.07 billion cubic meter of waste water are annually treated in public sewage treatment facilities - 0.1 per cent receive only mechanical treatment, 1.9 per cent undergo biological treatment without nutrient removal and 98 per cent pass through a biological treatment process with targeted nutrient elimination.
A major challenge for the future will be the elimination of pollutants in waste water which, to date, have not been taken into account such as pharmaceutical residues, antibiotics from animal husbandry or chemicals displaying hormone-like effects even in minute quantities. Current treatment technologies are not able to remove these trace substances. There are first tentative technologies such as special membranes or oxidisation processes which make a removal possible. However, to date there are no legal thresholds which could serve as a guidance for sewage plant operators.
A "trace substance strategy" is currently being developed under the auspices of the BMU