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3.1 tonnes of lead from municipal wastewater
statistikk
2012-12-14T10:00:00.000Z
Nature and the environment;Nature and the environment
en
avlut, Municipal wastewater, sewer system, treatment plant, sludge, grey water, black water, sewage, discharges to water, nitrogen emissions, phosphorus emissions, heavy metals, organic pollutants, organic material (COF and BOF5), waste feesWater and waste water , Pollution and climate, Nature and the environment
false

Municipal wastewater, 2011

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3.1 tonnes of lead from municipal wastewater

Estimates for 2011 show that Norwegian wastewater facilities discharged around 1.3 tonnes of lead into fresh waterways and coastal areas, while 1.8 tonnes absorbed into sewage sludge.

This is revealed in the new report Municipal wastewater: Expenditures, investments, discharges, treatment and disposal of sewage sludge 2011 - Wastewater fees 2012 (in Norwegian only, English abstract).

In comparison to national discharge and emission data, lead from wastewater constitutes around 3 per cent of the total (according to Miljøstatus the total discharges and emissions in 2009 were around 118 tonnes). Lead is considered to be acutely and chronically poisonous to animals and humans, and the authorities aim to continuously reduce discharges and use, with the aim of achieving a complete stop to discharges by 2020.

Furthermore, in 2011, the total level of mercury from wastewater amounted to 79 kg, while cadmium totalled 123 kg.

Estimated amount of heavy metals in sewage sludge and treated wastewater. The whole country. 2011. Kilogrammes
 
 Total amount
in sewage
sludge and
treated
wastewater		Amount in
treated
wastewater		Amount in
sewage
sludge 1
 
  Kilogrammes
Arsenic (As). 520.
Cadmium (Cd) 1235271
Chromium (Cr)5 7003 0002 700
Copper (Cu)32 90012 00020 900
Mercury (Hg)792950
Nickel (Ni)5 4003 8001 600
Lead (Pb)3 1001 3001 800
Zinc (Zn)72 70032 00040 700
 
1  Estimation based on average content of heavy metals
in sewage sludge and amount of sludge disposed.

Where do heavy metals in wastewater come from and where do they go?

Heavy metals in wastewater originate mainly from storm water (run-off from roads and streets) and cleaning and maintenance of cars and bikes, and washing of clothes. Wastewater is generally a minor source for heavy metals. At the treatment plants, part of the heavy metals will absorb into the sewage sludge - removed from the water phase - while another part will pass through the plant, released into the waterways together with treated wastewater.

Three out of five connected to high-grade treatment

In 2011, 60 per cent of Norway’s population were connected to high-grade treatment plants - biological and/or chemical treatment. This constitutes an increase from 58 per cent in 2009 and 59 per cent in 2010. Chemical/biological treatment as opposed to mechanical treatment can remove more of the pollutants from the wastewater before being discharged into rivers and water systems. This applies in particular to phosphorous and organic material, but also other types of pollutants.

Furthermore, the statistics show that 19 per cent of the population were connected to mechanical or other types of treatment, 4 per cent had direct discharges and the remaining 17 per cent of the population were connected to small wastewater facilities (less than 50 pe).

2 704 wastewater facilities serving 83 per cent of us

Estimates for 2011 show that a total of 2 704 municipal wastewater facilities (capacity 50 pe or more) were in operation for the whole or part of the year. These wastewater facilities treat wastewater for approximately 83 per cent of the population, which is around the same level as last year.

Number of wastewater facilities according to type of treatment and size. Facility with capacity 50 pe or more. 2011.

75 per cent of wastewater facilities under municipal control

Close to 75 per cent of the 2 704 municipal wastewater facilities are organised directly under the municipality. Private facilities in comparison constitute around 14 per cent, and are usually small in size (low capacity/few people connected).

Wastewater facilities, capacity and inhabitants connected by type of organisation. Wastewater facility 50 pe or more. The whole country. 2011]
 
OrganisationNumber of
wastewater
facilities		Number of
inhabitants
connected		Capacity
     (1 000 pe)
 
Total2 704       4 135 7376 714
 Per cent
Municipal departement/unit74.965.267.2
Inter-municipal cooperation with separate accounts0.113.911.9
Municipal business enterprice3.13.83.5
Inter-municipal company0.915.715.1
Municipal limited company1.90.60.6
Municipally owned party, foundation etc.0.00.00.0
Private limited company, party, foundation, public entity etc14.50.41.2
Unknown4.60.40.5
 

Furthermore, only a few facilities treat really large quantities of wastewater. Fifteen per cent of the wastewater facilities are 2 000 pe or larger, while 64 per cent have a capacity of 50-499 pe.

825 tonnes of phosphorous

For 2011, the discharges of phosphorous (tot-P) from the municipal wastewater sector have been estimated at 825 tonnes. This constitutes a 1.6 per cent increase compared to the year before. Per inhabitant connected, this discharge corresponds to 0.20 kg per year.

The phosphorous treatment efficiency of the wastewater sector as a whole has been estimated at 68.6 per cent.

Distribution in contribution margin ratio and full cost ratio. 2011. Per cent

Slight increase in costs of wastewater services

In 2011, the total cost for all municipalities was NOK 5.68 billion. This constitutes an increase of 4.5 per cent compared to 2010. The costs related to the wastewater sector are made up of capital costs and operating costs. The increase mentioned is due to an increase in operating and capital costs. The figures for the entire country are calculated based on the data reported in KOSTRA, with estimates for data missing. The estimates are based on data reported last year and average figures from the groups of municipalities in KOSTRA.

Wastewater fees are determined by the municipalities in accordance with the full cost principle. Local conditions such as patterns of built-up areas, topography, bedrocks in the ground, the need for pumping stations and treatment requirements are all factors behind the variation in fees.

A total of 45 per cent of the population live in municipalities with a contribution margin ratio of less than 100 per cent, which means that the incomes from fees are below the fee calculation basis.

At the same time, a total of 68 per cent of the municipalities have a full cost ratio between 98 and 102 per cent, and these municipalities are home to 76 per cent of the population. A major part of the population lives in municipalities where the costs for wastewater services are covered by fees.

The full cost ratio reflects the relationship between the income from fees and the fee calculation basis, and includes fund provisions and purchases from funds.