As part of the European Economic Area (EEA-agreement), Norway has implemented EUs directive on Urban Waste Water Directive (91/271/EEC and 98/15/EEC) into Norwegian law.
In 2023 there were 2 758 wastewater facilities in Norway with a capacity of more than 50 population equivalents (pe) according to the municipalities reports to the Norwegian Environment Agency. They treated wastewater from 88 per cent of Norway’s population. The share of the population connected to advanced treatment plants (chemical and/or biological treatment) were 65 per cent, while 21 per cent had mechanical or other treatment and 2 per cent of the population had direct discharges (untreated wastewater). The remaining population of around 740 000 was connected to the around 320 000 small wastewater facilities (less than 50 pe and thus including small individual facilities), which normally constitute a sludge separator, possibly with some additional filtration device in the end.
In total, the discharge from the municipal wastewater sector in 2023 is estimated to around 1 440 tonnes of phosphorus and 19 800 tonnes of nitrogen including also small wastewater facilities less than 50 pe and estimated leakage.
The strictest treatment permits of municipal wastewater were set in place in the 1990s, in attempts to reduce discharges of phosphorous and nitrogen into the coastal area Swedish boarder to Lindesnes. This originate from the North Sea Protocol, signed in 1987. Strict permits are also reflected in the statistics in the way that this area also show the highest percentage of inhabitants connected to high-grade treatment. Sensitive areas – as defined in EUs, draining into the North Sean/Skagerrak show a 90 percent off people living in the area connection rate to high-grade treatment, compared to normal areas of 80 percent and less sensitive areas 29 percent.
Discharges of wastewater along the coast from Lindesnes to Grense Jakobs elv (Russian boarder) undergo more laxed treatment permits, which is reflected in the statistics by a large number of mechanical treatment plants.
Compliance with treatment permits constitutes an important part of wastewater management, and the statistics show that out of 4.9 million people connected to moderate or large wastewater facilities (50 pe or larger) in 2023, around 72 per cent belong to a facility which comply with their treatment permits, 23 per cent where the facility do not comply and 5 per cent where there is unknown compliance (due to missing data about treatment requirements).
For 2023, the total amount of sewage sludge used for different purposes has been estimated to around 134 000 tonnes, measured in dry weight. Approximately 80 per cent of this amount was used in agriculture, in parks and other green spaces or delivered to soil producers.
Municipal wastewater fees set by the municipal authorities are in accordance with full cost regulations. The fee level generally varies due to differences in type of settlement patterns and geographical characteristics. The connection fee is a one-time payment by the user at the time of connecting to the existing wastewater pipeline-system. In 2023, the connection fee was on average NOK 13 455 (VAT excluded). The annual fee was on average NOK 5 266 per year in 2023 (VAT excluded).
In 2023, the municipalities’ annual costs totalled NOK 12.6 billion. The costs in the municipal wastewater sector are capital costs and operating expenditures.