Nitrogen and carbon removal from anaerobic digester effluents with low carbon to nitrogen ratios under feammox conditions.

Removal of nitrogen and carbon from anaerobic digester (AD) effluents is challenging for currently available technologies. Herein, effective treatment for real AD effluents was achieved via the feammox process by using a Multistage Feammox Bioreactor (MSFB). The reactor achieved the best performance with AD effluent of a low carbon to nitrogen (C/N) ratio of 2.

Ammonium and organic carbon co-removal under feammox-coupled-with-heterotrophy condition as an efficient approach for nitrogen treatment.

Nitrification is the rate limiting step in the nitrogen removal processes since nitrifiers have high oxygen demand, but poorly compete with aerobic heterotrophs. In a laboratory-scaled system, we investigated a process of ammonium oxidation under ferric-iron reducing condition (feammox) in the presence of organic carbon using influents with high NH and COD contents, and ferrihydrite as the only electron acceptor. Batch incubations testing influents with different NH and COD concentrations revealed that the [COD]/[NH] ratio of 1.