The Standard is published in May 2018, base on the German Edition from November 2017. This Standard sets out a common basis for the design, construction, and operation of planted and unplanted filters for biological treatment of municipal wastewater. Wastewater treatment with planted and unplanted filters is characterized by a simple structural design, a simple mode of operation, a low production of biomass and secondary sludge, a low use of external energy, and a high treatment efficiency, even for treatment systems with a small number of sewer connections. Limiting factors for the use of such processes are the comparatively large area requirements and the resulting costs. Due to the low specific area requirement, in particular vertical filters were realized for this reason. Conventional horizontal flow filters are described in this Standard only as a downstream (tertiary) treatment stage, no longer as a main (secondary) biological treatment stage.
In recent years, a large number of findings have been gained from the use of these procedures in Germany and Europe which were taken into account in the new version of the Standard. Newer test results for Primary treatment in multicompartment septic tanks were taken into account and new planted and unplanted filters were added. In addition, plants with raw wastewater filters for processing wastewater from combined sewer networks, a two-stage process with vertical flow filters, artificially aerated planted and unplanted filters, specifications for seasonally loaded treatment systems and systems for greywater treatment are described in detail.