Nitrification in Fixed Bed Reactors Treating Saline Wastewater Zur Erlangung des akademischen Grades eines DOKTOR-INGENIEURS Von der Fakultät für Bauingenieur-, Geo- und Umweltwissenschaften, Karlsruher Institut für Technologie (KIT) genehmigte DISSERTATION von Sudarno, MSc Boyolali - Indonesien Tag der mündlichen Prüfung : 6. May 2011 Hauptreferent : Prof. Dr. rer.nat. J. Winter Korreferent : Prof. Dr.-Ing. E.h. H. H. Hahn, PhD Karlsruhe 2011 Chapter 1 INTRODUCTION 1.1 Background Eutrophication describes a condition of water bodies having high nutrient contents especially of nitrogen and phosphorus compounds. An excessive content of nutrients stimulates biomass formation by algal blooms, which may excrete very toxic biocides and during decay can lead to oxygen starvation in water ecosystems. Oxygen deficiency leads to a reduced biodiversity of the macro- and microorganism populations. Fishes suffocate, the fish production is drastically diminished and the use of the water bodies is highly restricted. Eutrophication becomes a serious problem in many fresh water habitats and coastal areas throughout the world (UNEP 2006). Within 10 years, from 1987 to 1997, Germany successfully decreased 25 % of the total nitrogen emission into the water body of catchment areas. Nevertheless, the international goal of reducing nutrient emissions by 50 % from 1985 to 1995 could not be reached (Behrendt et al. 2002).