11. Nitrification can also occur in drinking water.12. Nitrification is the process by which ammonia ( ) is converted to nitrate ( ).13. Nitrification is the term describing the conversion of ammonia into nitrite and then into nitrate.14. The addition of chlorite ion to chloramine-treated water has been shown to control nitrification . 15. The biological aerated filter ( BAF ) system allows for year-round nitrification of wastewater. 16. Bacterioplankton play critical roles in global nitrogen fixation, nitrification , denitrification, remineralisation and methanogenesis. 17. Any remaining ammonium in the environment can undergo nitrification and denitrification to yield nitrate and nitrite. 18. Influence of oxic / anoxic fluctuations on ammonia oxidizers and nitrification potential in a wet tropical soil. 19. The first step of nitrification in the biofilter consumes alkalinity and lowers the pH of the system. 20. Heterotrophic microorganisms are important in oxidising carbon ( decomposition ) whereas autotrophic microorganisms are important in nitrification .