Comparison of the Nitrification Rate for Different Unit Processes

In Table 2.4 a comparison is made between the different nitrification rates as a function of the temperature, from data found in the literature. The results shown are presented either with the surface rate in g N/ m2 * day or the media volume rate in kg N/ m3 * day.

Results show that the submerged filters generally has high nitrification rates; in particular the submerged filter named biocarbone, developed by OTV in France, is among the unit processes with the highest nitrification rate. Generally the biofilm unit processes appear to have a higher nitrification rate than the activated sludge processes, expressed with the above indicated units.

Table 2.3 Comparison of the developed amount of suspended solids and yield coefficients in the different nitrifying and denitrifying unit processes. For comparison, data for heterotrophs are added to the list.

Process

Yield coefficient volatile suspended solids (VSS)

Sludge Production g VSS / m3 sewage

Activated sludge with nitrification

Trickling filter

Separate stage nitrification

Comb, suspended nit/denit

Separate stage denitri-fication with suspended unit

Separate stage denitri-fication with biofilter unit

0.6 g VSS / g BOD 0.4 g VSS / g BOD 0.1 g VSS / g NH4+ - N 0.5 g VSS / g BOD

120 80 2 100

Table 2.4 A comparison of the peak nitrification rate for various units, both attached and suspended growth processes, at different temperatures, a).

Volumetric nitrification rates (kg N/m3 • d) at various temperatures °C Reactor type The RBC reactor is indicated as kg N/m2 ■ d (superficial nitrification rate)

and results indicated in brackets.

Simultaneous nitrification and denitrification pilot plant b)

Biofilm-Controlled Nitrifying Trickling Filter (BCNTF)

Biocarbone (BAF and I. Kruger)

Linpor (foam cubes in suspension)

Packed bed reactor gravel (5 mm gravel)

Fluidized bed reactor High porosity medium, activated carbon

Activated sludge 0,12

Partly from Parker et al. (1990)

Halling-Serensen and Hjuler (1993)

Parker etat. (1989)

Gujer and Boller (1989)

Antonie (1974)

Rogella and Payraudeau (1987)

Rogella and Payraudeau (1987)

Gasser etat. (1974)

Metealf and Eddy (1991)

Wild etat. (1971) Starnberg etat. (1974)

processes are to be applied, pilot denitrification.

a) Data are reported for comparative purposes only. If any of these plant testing is recommended to verify removal rates.

b) Only reactor type that can perform simultaneous nitrification and

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