Urban waste water treatment per province and river basin district

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Regions Urban waste water treatment plants Numbers by type Mechanical treatment (number) Urban waste water treatment plants Capacity pollution equivalents by type Mechanical treatment (1 000 pollution equivalent) Urban waste water treatment plants Capacity inhabitant equivalents by type Mechanical treatment (1 000 inhabitant equivalents) Influent waste water Quantities Volume waste water (1 000 m3) Discharge of waste water (effluent) Quantities Volume waste water (1 000 m3) Sewage sludge Wet sewage sludge by destination Co-incineration at power plants (1 000 kg) Sewage sludge Dry solids by destination Co-incineration at power plants (1 000 kg)
Nederland 0 0 0 2,229,171 2,229,171 406,585 73,682
Noord-Nederland (LD) 0 0 0 246,983 246,983 54,708 12,337
Oost-Nederland (LD) 0 0 0 444,237 444,237 254,875 39,692
West-Nederland (LD) 0 0 0 955,693 955,693 80,740 17,341
Zuid-Nederland (LD) 0 0 0 582,258 582,258 16,262 4,311
Groningen (PV) 0 0 0 82,343 82,343 49,030 10,875
Fryslân (PV) 0 0 0 101,801 101,801 0 0
Drenthe (PV) 0 0 0 62,839 62,839 5,678 1,463
Overijssel (PV) 0 0 0 144,870 144,870 29,157 1,142
Flevoland (PV) 0 0 0 30,922 30,922 12,188 2,849
Gelderland (PV) 0 0 0 268,445 268,445 213,530 35,702
Utrecht (PV) 0 0 0 137,004 137,004 18,522 4,478
Noord-Holland (PV) 0 0 0 313,465 313,465 59,768 12,336
Zuid-Holland (PV) 0 0 0 446,895 446,895 2,450 527
Zeeland (PV) 0 0 0 58,329 58,329 0 0
Noord-Brabant (PV) 0 0 0 395,100 395,100 5,417 1,311
Limburg (PV) 0 0 0 187,158 187,158 10,846 3,000
The river Eems 0 0 0 87,564 87,564 49,030 10,875
The river Rijn (North Rijn) 0 0 0 117,644 117,644 0 0
The river Rijn (East Rijn) 0 0 0 429,921 429,921 235,686 35,000
The river Rijn (Central Rijn)
The river Rijn (West Rijn) 0 0 0 942,525 942,525 105,607 23,496
The river Maas 0 0 0 548,198 548,198 16,262 4,311
The river Schelde 0 0 0 103,319 103,319 0 0
Source: CBS.
Explanation of symbols

Table explanation


This table presents the most significant results of the annual survey Public treatment of urban waste water. The results are presented per province and river basin district (Rijn, Maas, Eems and Schelde) and include:
- number and capacity of the urban waste water treatment plants by type of treatment;
- the volume and concentration of organic matter, nutrients and heavy metals in the waste water running into waste water treatment plants (influent) and the volume of treated waste water (effluent). As of 2017, data on heavy metals are only inventoried for even years.
- the volume and destination of the sludge released, with nutrients and heavy metals. As of 2017, sludge data are only inventoried for even years.
Additional data on urban waste water treatment plants, process technology, energy consumption, generation of energy and sludge dewatering can be accessed on the Dutch version of StatLine.

Data available from: 1981

Status of the figures:
The figures in this table are definitive.

Changes as of 29 May 2026:
The figures of 2024 has been added.

When will new figures be published?
New figures on 2025 will be published by March 2027.

Description topics

Urban waste water treatment plants
The number and capacity of urban waste water treatment plants in the Netherlands where nearly all domestic waste water and waste water from the private sector is treated. The plants are all operated by regional water quality control authorities.
Numbers by type
Number of sewage water treatment plants broken down by method of treatment.
Mechanical treatment
Installation where suspended matter is extracted from waste water by settlement.
Capacity pollution equivalents by type
Capacity urban waste water treatment plant:
A value that indicates how much organic pollution theoretically can be treated by a waste water treatment plant.

The pollution equivalent is the official unit that quantifies the pollution in waste water; one pollution equivalent = 150 g TOD (Total Oxygen Demand).
One pollution equivalent is the daily quantity of oxygen-demanding material in the waste water of one person. The degree of pollution in the waste water produced by the private sector is also expressed in pollution equivalents.
This unit is used as of 2010, so for previous years no values are available.
Mechanical treatment
Installation where suspended matter is extracted from waste water by settlement.
Capacity inhabitant equivalents by type
Capacity urban waste water treatment plant:
A value that indicates how much organic pollution theoretically can be treated by a waste water treatment plant.

The capacity expressed in Inhabitant Equivalents is determined on basis of: one inhabitant equivalent = 54 g BOD (Biological Oxygen Demand).
One inhabitant equivalent is the daily quantity of oxygen-demanding, organic substances in the waste water of one person.
Nowadays, the use of the unit inhabitant equivalent is decreasing. The most common unit is the pollution equivalent.
Mechanical treatment
Installation where suspended matter is extracted from waste water by settlement.
Influent waste water
Data on concentrations and quantities of pollutants in the waste water running into urban waste water treatment plants (influent).
Quantities
Volume waste water
The annual volume of influent waste water.
Discharge of waste water (effluent)
Data on concentrations and quantities of pollutants in treated waste water (effluent) discharged from urban waste water treatment plants.
Quantities
Volume waste water
The annual volume of effluent waste water.
Sewage sludge
Residue of treated waste water consisting of suspended solids and excess active sludge (biomass). Sewage sludge is measured including water (see Total wet sludge) or as dry solids.
Wet sewage sludge by destination
The volume of wet sewage sludge, i.e. including water by destination (processing method).
Co-incineration at power plants
Sewage sludge used as a secondary fuel at a power plant.
Dry solids by destination
Discharged sewage sludge in kilogrammes of dry solids by destination (processing method). Dry solid is the residue of sewage sludge after evaporation at 105 degrees centigrade.
Co-incineration at power plants
Sewage sludge used as a secondary fuel at a power plant.