GPS-X Technical Reference

143 Suspended Growth Models
21. Storage of PHA by PAO using propionate: This is a new process and
describes the storage of PHA by PAO using propionate. The kinetics and
stoichiometry of the process is based on concepts used in describing
process #20.
22. Growth of PAO on PHA using O 2 as electron acceptor: The stoichiometry
and rate expression for this process is the same as ASM2d.
23. Storage of XPP on PHA using O 2 as electron acceptor: The stoichiometry
and rate expression for this process is the same as ASM2d.
24. Growth of PAO on PHA using NO 3 as electron acceptor: This process of
PAO growth takes place in the presence of NO 3-N. The stoichiometry of this
process is developed by considering partial reduction of NO 3-N to NO 2-N.
The rate expression for the process uses an inhibition term for oxygen and a
saturation term for the NO 3-N. The reaction rate expression also reduces the
amount of PAO biomass by the fraction of NO 3-N to total NO X nitrogen
available in the system. It is assumed that when the PAO biomass is
converting NO 3-N to NO 2-N, it is not participating in the conversion of NO 2-
N to N 2 gas.
25. Storage of XPP on PHA using NO 3 as electron acceptor: In this process
the storage of poly-phosphate takes place while the stored PHA compounds
are oxidised using NO 3-N as an electron acceptor. Only partial reduction of
NO 3-N to NO 2-N is considered in process stoichiometry formulation. Similar
to the process #24, a reduction factor equal to the ratio of NO 3-N to NO X-N
concentration is applied to account for fraction of total biomass mediating
this process.
26. Growth of PAO on PHA using NO 2 as electron acceptor: This process of
PAO growth takes place in the presence of NO 2-N. The stoichiometry of this
process is developed by considering partial reduction of NO 2-N to N 2-N.
The rate expression for the process uses an inhibition term for oxygen and a
saturation term for the NO 2-N. The reaction rate expression also reduces the
amount of PAO biomass by the fraction of NO 2-N to total NO X nitrogen
available in the system. It is assumed that when the PAO biomass is
converting NO 2-N to N 2-N, it is not participating in the conversion of NO 3-N
to NO 2-N.
GPS-X Technical Reference