Urban waste water treatment per province and river basin district
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
- Influent waste water
- Data on concentrations and quantities of pollutants in the waste water running into urban waste water treatment plants (influent).
- Quantities
- 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.
- Concentrations
- The arithmetic mean of concentrations.
- 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.
- 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
- 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.
- Concentrations
- The arithmetic mean of concentrations.
- 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.
- 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).
- Landfill
- Dumping of sludge on regional landfill sites or special sludge depots.
- 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.
- Landfill
- Dumping of sludge on regional landfill sites or special sludge depots.
- 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