Municipal wastewater 2015

This report summarizes 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 2015 there were 2 688 wastewater facilities in Norway with a capacity of more than 50 population equivalents (pe). They treated wastewater from 85 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 18 per cent had mechanical or other treatment and 2 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 additional filtration device in the end.

In 2015, a total of 910 tonnes of phosphorus and 15 500 tonnes of nitrogen were discharged by wastewater facilities ((≥ 50 pe) into the aquatic environment. Compared to 2002 this constitutes an increase of 1 and 31 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 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 (0.06 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 (90 per cent) is also higher compared to the rest of the country (41 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 (2.08 kilogram) combined with high treatment efficiency (58 per cent).

Totally, including also small wastewater facilities less than 50 pe and estimated leakage, the discharge from the municipal wastewater sector in 2015 is estimated to around 1 420 tonnes of phosphorus and 19 610 tonnes of nitrogen.

For 2015, it has been roughly estimated a discharge from wastewater treatment plants ((≥ 50 pe) of 17 kilogram mercury, 800 kilogram lead and 37 kilogram cadmium. As for organic material it has been estimated a discharge of around 43 800 tonnes of biological oxygen demand (BOD5) or 104 500 tonnes of chemical oxygen demand (COD). This corresponds to 9.8 and 23.5 kilogram per capita of BOD5 and COD, respectively.

For 2015, the total amount of sewage sludge used for different purposes has been estimated to around 141 900 tonnes, measured in dry weight. Approximately 78 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 2016, the connection fee was on average NOK 14 700 (VAT excluded). The annual fee was on average NOK 3 781 per year in 2016 (VAT excluded).

In 2015, the municipalities’ annual costs totaled NOK 7 billion. The costs in the municipal wastewater sector are capital costs and operating expenditures.