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 biofilm model. To test the new model in detail, a pilot-scale (200 L) trickling filter was built and operated. Using this setup, removal of the surfactant LAS was measured under different well-characterized operating conditions. The new model could be fitted to data on LAS removal in the pilot-scale filter as well as in two full-scale domestic treatment plants. The same biodegradation 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 concentrations on the biodegradation rate should be further investigated.