Development of a chemical fate model for trickling filters based on the activated sludge model Simple Treat: A case study for LAS

A new chemical fate model for trickling filter wastewater treatment plants was developed, using the same principles as the steady-state nonequilibrium activated sludge model SimpleTreat, in combination with an existing biofil m model. To test the new model in detail, a pilot-scale (200 L) trickling f ilter was built and operated. Using this setup, removal of the surfactant L AS was measured under different well-characterized operating conditions. Th e new model could be fitted to data on LAS removal in the pilot-scale filte r as well as in two full-scale domestic treatment plants. The same biodegra dation rate coefficient (derived from activated sludge data) could be used in all cases, except for one laboratory experiment with higher LAS influent concentrations. It is concluded that the effect of high influent concentra tions on the biodegradation rate should be further investigated.