The largest source of water supply and agricultural product contamination is wastewater from homes, businesses, and municipalities. As a result, this book chapter focused on wastewater treatment methods for safe agriculture, notably the Trickling Filter (TF) technology. Next, the kinetics and physical mechanisms of mass change in biofilm reactors were examined. Biological processes that contribute to pollution biodegradation include the removal of organic waste, nitrification or partial nitrification, denitrification, and anammox. Wastewater treatment also requires an analysis of model data. The activated sludge and biofilm diffusion models are completed, the Retention Time Distribution analysis for hydrodynamic modeling is examined, and some of the most recent hydraulic models are presented. Furthermore, to build and design new TF systems and retrofit current TFs, the answers to the TF system's operational and performance issues are extensively analyzed and resolved.