Urban waste water treatment per province and river basin district
Explanation of symbols
Table description
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 6 April 2021:
The figures of 2019 has been added.
Within the Topics, the underlying breakdown into type of wastewater treatment is expanded with two new types.
When will new figures be published?
New figures on 2020 will be published by March 2022.
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.
- Total number
- The total number of urban waste water treatment plants in the Netherlands.
- Trickling filters
- Waste water is sprinkled over a layer of porous stones covered with bacteria (biofilm). Thus, organic compounds in the waste water are degraded.
- Aeration tanks
- Pre-settled waste water runs through an intensively aerated basin containing active sludge (bacteria). Organic pollutants are degraded by oxygen and active sludge. The treatment process takes up only a short period of time and the sludge load is high which is typical of aeration basins.
- Oxidation tanks
- Operates by the same principle as the aeration tank but the sludge load is significantly lower. The resulting sludge is highly mineralised and will therefore decompose more slowly.
- Oxidation ditches
- In oxidation ditches, waste water is directed through a aeration circuit several times. The process takes up 2 or 3 days. Consequently, the sludge load is extremely low.
- Carrousels
- This technology is chiefly applied in large installations. Typical of carrousels are the depth (between 2 to 4 metres) and the aeration method.
- Discontinuous systems
- Oxidation basins and oxidation ditches. Waste water is let in batch-controlled.
- Parallel installations
- Various combinations of treatment systems (so-called 'streets') are applied in one installation.
- Multi-stage installations
- A serial process consisting of two systems, for instance, a trickling filter and an aeration basin. The waste water runs through both stages.
- Compact installations
- A system consisting of a basin subdivided into four segments. Waste water flows into the aeration segment. Subsequently, the sludge is separated in the central aeration zone. Then part of the sludge is conditioned in the reaeration zone and led back into the aeration zone. The other part (surplus sludge) is stabilised in the sludge mineralisation zone and subsequently removed.
- Nereda granular sludge reactor
- In the Nereda granular sludge reactor the wastewater is purified by micro-organism clogged in natural granular structures of high density. These granules have a high biological activity and make it easy to separate the micro-organisms from the treated wastewater.
As from 2019 this new treatment type is distinghuished separately in Statline. In the period 2011-2018 already 4 Nereda systems became operational. Until 2019, these installations were classified as oxidation tanks and/or discontinous systems.
- Hybrid Nereda - active sludge system
- System consisting of a parallel operated Nereda granular sludge reactor and activated sludge system.
In the Nereda granular sludge reactor the wastewater is purified by micro-organism clogged in natural granular structures of high density. These granules have a high biological activity and make it easy to separate the sludge from the treated wastewater.
In activated sludge systems the wastewater is treated in bassins with flocculated sludge . This sludge clumps exists of microorganisms that feed on the the organic pollution in wastewater.
As from 2019 this new treatment type is distinghuished separately in Statline. In the period 2013-2018 already 2 hybrid Nereda - activated sludge sytems became operational. Until 2019, these installations were classified as parallel installations.
- 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.- Total capacity pollution equivalents
- Trickling filters
- Waste water is sprinkled over a layer of porous stones covered with bacteria (biofilm). Thus, organic compounds in the waste water are degraded.
- Aeration tanks
- Pre-settled waste water runs through an intensively aerated basin containing active sludge (bacteria). Organic pollutants are degraded by oxygen and active sludge. The treatment process takes up only a short period of time and the sludge load is high which is typical of aeration basins.
- Oxidation tanks
- Operates by the same principle as the aeration tank but the sludge load is significantly lower. The resulting sludge is highly mineralised and will therefore decompose more slowly.
- Oxidation ditches
- In oxidation ditches, waste water is directed through a aeration circuit several times. The process takes up 2 or 3 days. Consequently, the sludge load is extremely low.
- Carrousels
- This technology is chiefly applied in large installations. Typical of carrousels are the depth (between 2 to 4 metres) and the aeration method.
- Discontinuous systems
- Oxidation basins and oxidation ditches. Waste water is let in batch-controlled.
- Parallel installations
- Various combinations of treatment systems (so-called 'streets') are applied in one installation.
- Multi-stage installations
- A serial process consisting of two systems, for instance, a trickling filter and an aeration basin. The waste water runs through both stages.
- Compact installations
- A system consisting of a basin subdivided into four segments. Waste water flows into the aeration segment. Subsequently, the sludge is separated in the central aeration zone. Then part of the sludge is conditioned in the reaeration zone and led back into the aeration zone. The other part (surplus sludge) is stabilised in the sludge mineralisation zone and subsequently removed.
- Nereda granular sludge reactor
- In the Nereda granular sludge reactor the wastewater is purified by micro-organism clogged in natural granular structures of high density. These granules have a high biological activity and make it easy to separate the micro-organisms from the treated wastewater.
As from 2019 this new treatment type is distinghuished separately in Statline. In the period 2011-2018 already 4 Nereda systems became operational. Until 2019, these installations were classified as oxidation tanks and/or discontinous systems.
- Hybrid Nereda - active sludge system
- System consisting of a parallel operated Nereda granular sludge reactor and activated sludge system.
In the Nereda granular sludge reactor the wastewater is purified by micro-organism clogged in natural granular structures of high density. These granules have a high biological activity and make it easy to separate the sludge from the treated wastewater.
In activated sludge systems the wastewater is treated in bassins with flocculated sludge . This sludge clumps exists of microorganisms that feed on the the organic pollution in wastewater.
As from 2019 this new treatment type is distinghuished separately in Statline. In the period 2013-2018 already 2 hybrid Nereda - activated sludge sytems became operational. Until 2019, these installations were classified as parallel installations.
- 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.
- Pollution Equivalents
- 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.
- Chemical oxygen demand (COD)
- Chemical oxygen demand (COD). Measure of the amount of oxygen consumed when a substance is degraded chemically.
- Biochemical oxygen demand (BOD)
- Biological oxygen demand (BOD). Measure of the amount of oxygen consumed when a substance is biodegraded.
- Nitrogen compounds as N (total)
- The total amount of nitrogen in organic compounds (e.g. proteins) and inorganic compounds (e.g. nitrate and ammonium)
- Phosphorus compounds as P (total)
- The total amount of phosphates and other phosphorus compounds in waste water, measured as phosphorus (P).
- Copper
- Chromium
- Zinc
- Lead
- Cadmium
- Nickel
- Mercury
- Arsenic
- 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.
- Pollution Equivalents
- 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.
- Chemical oxygen demand (COD)
- Chemical oxygen demand (COD). Measure of the amount of oxygen consumed when a substance is degraded chemically.
- Biochemical oxygen demand (BOD)
- Biological oxygen demand (BOD). Measure of the amount of oxygen consumed when a substance is biodegraded.
- Nitrogen compounds as N (total)
- The total amount of nitrogen in organic compounds (e.g. proteins) and inorganic compounds (e.g. nitrate and ammonium).
- Phosphorus compounds as P (total)
- The total amount of phosphates and other phosphorus compounds in waste water, measured as phosphorus (P).
- Copper
- Chromium
- Zinc
- Lead
- Cadmium
- Nickel
- Mercury
- Arsenic
- 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).
- Total wet sludge
- Total wet sludge discharged.
- Agriculture
- Application of manure or soil improver in agriculture. Due to rigid legislation impossible since 1995.
- Wet oxidation
- Wet oxidation of sludge in so-called VerTech installations: the sludge is oxidised under high pressure in a deep shaft.
- Composting
- Landfill
- Dumping of sludge on regional landfill sites or special sludge depots.
- Incineration
- Incineration of sludge in special sludge incineration plants or in household waste incinerators.
- Cement industry
- Co-incineration in cement ovens.
- Co-incineration at power plants
- Sewage sludge used as a secondary fuel at a power plant.
- Other destinations
- Mainly reuse.
- 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.
- Total dry solids
- Agriculture
- Application of manure or soil improver in agriculture. Due to rigid legislation impossible since 1995.
- Wet oxidation
- Wet oxidation of sludge in so-called VerTech installations: the sludge is oxidised under high pressure in a deep shaft.
- Composting
- Landfill
- Dumping of sludge on regional landfill sites or special sludge depots.
- Incineration
- Incineration of sludge in special sludge incineration plants or in household waste incinerators.
- Cement industry
- Co-incineration in cement ovens.
- Co-incineration at power plants
- Sewage sludge used as a secondary fuel at a power plant.
- Other destinations
- Mainly reuse.
- Nutrients and heavy metals
- The total weight of nutrients and heavy metals removed with the sludge. Most heavy metals adsorb strongly to the sludge particles.
- Ashes
- The residue of non-inflammable, inorganic matter after incineration.
- Nitrogen compounds as N
- The total amount of nitrogen in organic compounds (e.g. proteins) and inorganic compounds (e.g. nitrate and ammonium).
- Phosphorus compounds as P
- The total amount of phosphorus in sewage sludge is analysed as P205 (diphosphorus pentoxide) converted to P total.
- Copper
- Chromium
- Zinc
- Lead
- Cadmium
- Nickel
- Mercury
- Arsenic