Within the framework of environmental statistics, Statistics Netherlands collects data on the treatment of urban waste water and on the private treatment of waste water of mainly industrial origin. Urban or public wastewater treatment concerns the treatment of wastewater that is discharged into the sewer by households and companies. Private wastewater treatment involves companies and institutions that have their own treatment plant. In the treatment plants, the contaminants are removed from the supplied waste water (influent) by means of mechanical, biological and/or physico-chemical treatment techniques. The treated waste water (effluent) is discharged into the surface water. Wastewater treatment produces a residual product, the sewage sludge. In sewage sludge from biological installations, the organic substances can be further broken down (sludge fermentation). This process releases biogas, which can be used for energy generation. The sewage sludge is then optionally stripped of excess water (dewatering). Depending on the quality, the sludge can then be reused (for compost preparation, for example) or it will eventually be dumped or incinerated. This table contains part of the results of the annual wastewater treatment sludge survey of companies and institutions: the quantities and destination of the sewage sludge released by private companies with their own wastewater treatment plant. All data are broken down by company class according to SBI 2008, sludge type, treatment type or class of dry matter. Data available: 1993-2009 Status of the figures: The figures are final. Changes as of August 9, 2012: The table has been discontinued because the data has now been split over 2 new tables. Data for 2010 and later on the discharge of sewage sludge according to the SBI2008 classification are included in the StatLine table Waste water treatment at companies; by industry (SBI 2008). Data on discharge of sewage sludge according to sludge characteristics are included in the StatLine table Waste water treatment at companies; discharge sewage sludge to destination.
