Municipal wastewater

This report summarise the most important findings with regard to status of the municipal wastewater sector in Norway, and covers topics like expenditures and investments, fees, discharges of nitrogen, phosphorus, heavy metals, a few organic pollutants, treatment efficiencies, number of wastewater treatment plants, capacity, number of people connected, heavy metal content in sewage sludge and disposal of sewage sludge.

In 2012 there were 2 685 wastewater facilities in Norway with a capacity of more than 50 population equivalents (pe). They treated wastewater from 84 per cent of Norway’s population. The share of the population connected to advanced treatment plants (chemical and/or biological treatment) were 62 per cent, while 19 per cent had mechanical or other treatment and 3 per cent of the population had direct discharges (untreated wastewater). The remaining population was connected to the around 330 000 small wastewater facilities (less than 50 pe and thus including small individual facilities), which normally constitute a sludge separator, possibly with some sort of filtration device in the end.

In 2012, a total of 824 tonnes of phosphorus and 13 700 tonnes of nitrogen were discharged by wastewater facilities (( 50 pe) into the aquatic environment. Compared to 2002 this constitutes an increase of 13 and 16 per cent in regards to phosphorus and nitrogen respectively.

The main focus in terms of wastewater treatment has from authority levels been directed towards discharges into the water basins leading down to Skagerrak and the North Sea – the location of the most sensitive areas, with low critical loads towards pollution. These areas are bound by stricter discharge regulations compared to the rest of the country (Western-, Mid- and Northern Norway). This is also reflected in the statistics with noticeably lower phosphorus discharges per capita connected to treatment plants in the North Sea counties (0.05 kilogram) compared to the rest of the country (0.41 kilogram). The average treatment efficiency – removal of polluting agents by treatment plants – for phosphorus in the North Sea counties (92 per cent) is also higher compared to the rest of the country (42 per cent). The same picture applies to nitrogen, although the differences are less noticeable. It is particularly the counties of Oslo and Akershus which show low discharges per capita of nitrogen (1.70 kilogram) combined with high treatment efficiency (66 per cent).

Totally, including also small wastewater facilities less than 50 pe and estimated leakage, the discharge from the municipal wastewater sector in 2012 is estimated to around 1 300 tonnes of phosphorus and 17 700 tonnes of nitrogen.

For 2012, it has been roughly estimated a discharge from wastewater treatment plants (( 50 pe) of 27 kilogram mercury, 1 200 kilogram lead and 45 kilogram cadmium. As for organic material it has been estimated a discharge of around 38 100 tonnes of biological oxygen demand (BOD5) or 115 200 tonnes of chemical oxygen demand (COD). This corresponds to 9.0 and 27.2 kilogram per capita of BOD5 and COD, respectively.

For 2012, the total amount of sewage sludge used for different purposes has been estimated to around 122 000 tonnes, measured in dry weight. Approximately 84 per cent of this amount was used in agriculture, in parks and other green spaces or delivered to soil producers.

Municipal wastewater fees are in accordance with full cost regulations set by the municipal authorities. 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 2013, the connection fee was on average NOK 13 680 (VAT excluded). The annual fee was on average NOK 3 433 per year in 2013 (VAT excluded). This is an increase of around 2.7 per cent compared to last year.

In 2012, the municipalities’ annual costs totalled NOK 5.87 billion.