Effect of COD/N Ratio on Growth and Adaptation of Nitrifying Bacteria

Document Type: Original Article


1 Department of Environmental Health Engineering, Kermanshah University of Medical Sciences, Kermanshah, Iran.

2 Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.


Acclimation of nitrifying bacteria using inorganic carbon source (bicarbonate) and organic
carbon source (bicarbonate + glucose) was performed in this study. Sequential batch reactors
were inoculated by activated sludge (mixed culture of heterotrophic and nitrifying bacteria), and
fed by synthetic wastewater contain high concentration of ammonium (1000 mg·L
-1). Adapted
nitrifying bacteria, only using bicarbonate as carbon source, caused nitrification at a rate of 41
mg L
-1 h-1. The second reactor, which using bicarbonate and glucose as carbon source due to
high C/N ratio resulting high growth of heterotrophic bacteria and result revealed a minor effect
on nitrifying bacteria, and complete removal of ammonium occurred.