The practice of using the wastewater of the city of Braunschweig for irrigation on the surface areas of the Braunschweig Wastewater Association, over decades, starting in 1954, has changed from being a disposal of raw wastewater to a sprinkle irrigation of biologically treated wastewater including the use of the nutrients from sewage sludge. Future requirements on the disinfection of wastewater and also the expansion of agricultural crop growing portfolios could require the installation of a wastewater disinfection system. For this various processes have been tested in pilot trials. Generally, UV disinfection with long project run times and high average usage of the processing capacity are advantageous whereas short project run times or a lower utilisation of the maximum capacity rather favour a dosing of performic acid. A near-natural secondary treatment on the other hand proved itself to be not reliable enough.