Lowering of Ammonia Nitrogen Concentration in the Nitrification Effluent - The Lower, the Better?

The fraction of electron donor that is coupled with electron acceptor and the fraction of electron donor captured through cell synthesis in the tertiary denitrification (DN) system using methanol (MEOH) as the exogenous electron donor have been demonstrated in the field or laboratory (Dawson and Murphy, 1975; Engberg and Schroeder, 1975; Odegaard, et al., 1995; Mokhayeri et al., 2006). The quantification of mass of electron donor COD required to reduce a given mass of electron acceptor nitrate nitrogen (ΔC/ΔN) has also been demonstrated in the field or laboratory (Engberg and Schroeder, 1975; Koopman and Wonderlick, 1990). Despite the fact that DN stoichiometric and kinetic parameters for heterotrophic denitrifiers using MEOH has been well known and documented (Koopman and Wonderlick, 1990; Christensson et al., 1994; Mokhayeri et al., Nyberg et al., 1996; Dold et al., 2005), it has not yet been demonstrated that how different N-sources affect the portion of the electrons used for cell synthesis and portion of electrons used for respiration reaction, especially in the full-scale tertiary DN system, and accurately determining ΔC/ΔN ratio without MEOH COD breakthrough are poorly understood when ammonia nitrogen(NH4+-N) is not available for heterotrophic denitrifies cell synthesis.