CENSUS – Wastewater Treatment

Detect and quantify bacteria responsible for biological nitrogen removal

The CENSUS technology can be used to characterize and quantify specific bacteria and microbial processes responsible for biological nitrogen removal.  Typically, nitrogen removal is a two step process of oxidation of ammonia nitrogen to nitrate (nitrification) and reduction of nitrate to nitrogen gas (denitrification).  Nitrifying bacteria are generally sensitive organisms susceptible to inhibition by organic compounds, inorganic agents, and pH values outside a relatively narrow optimum range (7.5 to 8.6).  Furthermore, growth rates of nitrifying bacteria are frequently lower than those of heterotrophs responsible for carbonaceous BOD removal so competition between nitrifying bacteria and heterotrophs can be an issue in single sludge wastewater treatment designs.  Although system configurations vary considerably, the second step in nitrogen removal, denitrification, is performed in a separate, anoxic chamber or zone where recycled or endogenous BOD fuels the denitrification process.

CENSUS – Wastewater Targets include:

Ammonia Oxidizing Bacteria (AMO): Quantification of ammonia oxidizing bacteria responsible for nitrification, the first step in biological nitrogen removal.

Ammonia Oxidizing Archaea (AOA): Quantification of ammonia oxidizing Archaea responsible for nitrification, the first step in biological nitrogen removal.

Denitrifying Bacteria (DNF): During the second step of biological nitrogen removal, the nitrate produced during nitrification is used as a terminal electron acceptor by denitrifying bacteria converting nitrate to nitrogen gas.

Archaeal Nitrite Reducers (ADNF): Similiar to the DNF assay, this targets denitrifying archaeal organisms.

Anaerobic Ammonia Oxidizing Bacteria (AMX):  Quantifies the two types of nitrite reductase genes (nirS and nirK) found in anaerobic ammonia oxidizing bacteria.