Design of biological phosphorus removal
accumulate or release phosphate and do not normally influence the phosphorus
removal process ..
A shortage of easily degradable matter can be compensated for in several ways:
a.
external input of acetic acid,
b.
external supply of industrial wastewater,
c.
increased hydrolysis/fermentation in the anaerobic tank by increasing the
retention time,
d.
separate hydrolysis of sludge or wastewater which is subsequently supplied
to the anaerobic tank, see Fig 8.5.
The input of oxygen to the anaerobic tank will have the same effect as the input of
nitrate, that is, there will be a consumption of easily degradable organic matter. The
input of oxygen can take place with the flow of recycle sludge (normally it is no
problem), or by aeration of the anaerobic tank in connection with the mixing/turbulence which is necessary to keep the biomass suspended.
A third problem for the biological phosphorus removal may be the release of
phosphorus from the sludge before it is removed from the plant. This may take
place if anaerobic conditions occur in some of the other tanks simultaneously with
the presence of easily degradable organic matter. It will be a risk in connection with
the input of an external carbon source in excess for the denitrification. When nitrate
has been removed, a release of phosphorus from the sludge will take place. The
aerobic sludge age should be kept as low af possible. The higher ex,aerobict the less
efficient the bio-P process will be.
References
/1/ Ramadori, R. (ed.) (1987): Biological Phosphate Removal from Wastewater.
Proceedings of an IAWPRC Specialized Conference held in Rome 28-30
September 1987. Pergamon Press, London. (Advances in Water Pollution
Control).
/2/ Henze, M., Gujer, W. Mino, T., Matsuo, T., Wentzel, M.C. and G. v. R. Marais
(1995): Activated Sludge Model No.2. IAWQ. Sci. and Techn. Report. No.3,
IAWQ, London.
284
accumulate or release phosphate and do not normally influence the phosphorus
removal process ..
A shortage of easily degradable matter can be compensated for in several ways:
a.
external input of acetic acid,
b.
external supply of industrial wastewater,
c.
increased hydrolysis/fermentation in the anaerobic tank by increasing the
retention time,
d.
separate hydrolysis of sludge or wastewater which is subsequently supplied
to the anaerobic tank, see Fig 8.5.
The input of oxygen to the anaerobic tank will have the same effect as the input of
nitrate, that is, there will be a consumption of easily degradable organic matter. The
input of oxygen can take place with the flow of recycle sludge (normally it is no
problem), or by aeration of the anaerobic tank in connection with the mixing/turbulence which is necessary to keep the biomass suspended.
A third problem for the biological phosphorus removal may be the release of
phosphorus from the sludge before it is removed from the plant. This may take
place if anaerobic conditions occur in some of the other tanks simultaneously with
the presence of easily degradable organic matter. It will be a risk in connection with
the input of an external carbon source in excess for the denitrification. When nitrate
has been removed, a release of phosphorus from the sludge will take place. The
aerobic sludge age should be kept as low af possible. The higher ex,aerobict the less
efficient the bio-P process will be.
References
/1/ Ramadori, R. (ed.) (1987): Biological Phosphate Removal from Wastewater.
Proceedings of an IAWPRC Specialized Conference held in Rome 28-30
September 1987. Pergamon Press, London. (Advances in Water Pollution
Control).
/2/ Henze, M., Gujer, W. Mino, T., Matsuo, T., Wentzel, M.C. and G. v. R. Marais
(1995): Activated Sludge Model No.2. IAWQ. Sci. and Techn. Report. No.3,
IAWQ, London.
284