Comparison of combined and separated biological aerated filter (BAF) performance for pre-denitrification/ nitrification of municipal wastewater

Abstract

The performance of two systems of semi-industrial up-flow biological aerated filters (BAF) with pre-denitrification followed by nitrification was studied and compared under various operating and loading conditions. The first system consisted of two separate reactors for the denitrification and the nitrification step, whereas in the second system the aerobic nitrification zone was packed on top of the anoxic denitrification zone in one reactor. The second system potentially offers substantial savings in investment costs and space requirements for a large scale treatment plant. Regarding the elimination of carbonaceous pollution and denitrification the systems did not show significant differences. However, nitrification in the combined system suffered from the mixing of different biocenosis by daily backwashing and was reduced to 50-70% of the separated system's performance. Factors such as oxygen concentration, raw water composition and loading rates affected both systems' nitrification rates in similar ways. Since it is impossible to optimise the nitrification and denitrification processes separately, the combined system should only be considered for large scale applications if space is very scarce and if a stable raw water composition can be expected. If strict limit values for nitrate have to be met in the effluent, a combination of pre- and post-denitrification is advantageous and advisable.

Comparative study of the nitrification characteristics of two different nitrifier immobilization methods

“…Fixed biofilm systems have generally been the preferred method of immobilization in wastewater treatment because of their simple, reliable and stable characteristics and ease of use in small-scale treatment (Zhu and Chen 2002). The examples of fixedfilm reactors including trickle filters (Kamstra et al 1998), submerged biological aerated filters (Rother et al 2002), rotating biological contactors (Chen et al 2006a, b), fluidized bed reactors (Pruden et al 2003) and suspended carrier biofilm reactors (Wang et al 2005) have been investigated to remove nutrients and other pollutants from both household and industrial wastewater.…”

Estudio Del Proceso De Nitrificación Y Desnitrificación Vía Nitrito Para El Tratamiento Biológico De Corrientes De Agua Residual Con Alta Carga De Nitrógeno Amoniacal

“…Estos sistemas involucran la filtración con la degradación de la materia orgánica, y la nitrificación o desnitrificación. Muchas de las aplicaciones industriales operan en flujo ascendente y se destinan a la nitrificación del efluente de un sistema de fangos activados, y a la postdesnitrificación mediante la adición de carbono orgánico (Rother et al, 2002).…”