Standard ATV-DVWK-A 281E Dimensioning of Trickling Filters and Rotation Biological Contactors

The biological stage of wastewater treatment plants, employing trickling filters and rotating biological contactors
without sludge return feed, is dealt with in this Standard. The standard applies only for rotating biological
contactors without artificial aeration for the supply of the biofilm with the required oxygen.
A detailed description of the theoretical basic elements and practical application of both the fixed bed processes
is contained in the ATV Handbook „Biologische und weitergehende Abwasserreinigung“ [“Biological
and Advanced Wastewater Treatment”] and „Mechanische Abwasserreinigung“ [“Mechanical Wastewater
Treatment”]. The development of the trickling filter process and the rotating biological contactor as well as
the factors on their treatment efficiency are covered in advanced literature.
As with all aerobic processes for biological wastewater treatment, the contact between biomass and
wastewater is to be established and the biomass is to be supplied with oxygen. With the trickling filter process
the wastewater is spray irrigated over the filter material so that, during the dripping process, the contact
between biomass and wastewater is established. In general, aeration is without application of further energy.
With rotating biological contactors the partially submerged filter material is rotated about its longitudinal
axis with the application of energy. During the emergent phase of the material the biofilm can take up
oxygen from the surrounding air and in the submerged phase the pollutants from the wastewater.