Plant types, anaerobic processes
Fig 9.10 Fixed anaerobic filter. Suitable for pretreatment of(warm) wastewater from the food
industry. Gas is collected from the top of the filter.
problems are reinforced by anaerobic processes producing gas bubbles which can
inhibit the separation of water and granules at the top of the filter. The gas bubbles
may also cause problems in the form of adhesion of the biofilm as they can be
produced between the film and the carrier and thus causing sloughing off of the
biofilm.
In fluidized filters, the filter media are cleaned mechanically for the adhered biomass whereas it is the aim of the function of the expanded filter that the treatment
takes place in the filter itself in that the filter particles rub against each other. In the
rotating disc, the sloughing off of the slime is controlled by the rotation rate of the
disc.
recycle
Fluidized filter
sludge
raw wastewater
Expanded filter
sludge
Rotating discs
Fig 9.11 Exotic anaerobic filter processes. Normally used without final settling. The height of
the filter layer in the fluidized filter is controlled by withdrawal of filter grains (not
shown in the figure) which are returned in the column after the treatment. The treated
sludge can be treated separately or be mixed in the treated flow of water.
294
Fig 9.10 Fixed anaerobic filter. Suitable for pretreatment of(warm) wastewater from the food
industry. Gas is collected from the top of the filter.
problems are reinforced by anaerobic processes producing gas bubbles which can
inhibit the separation of water and granules at the top of the filter. The gas bubbles
may also cause problems in the form of adhesion of the biofilm as they can be
produced between the film and the carrier and thus causing sloughing off of the
biofilm.
In fluidized filters, the filter media are cleaned mechanically for the adhered biomass whereas it is the aim of the function of the expanded filter that the treatment
takes place in the filter itself in that the filter particles rub against each other. In the
rotating disc, the sloughing off of the slime is controlled by the rotation rate of the
disc.
recycle
Fluidized filter
sludge
raw wastewater
Expanded filter
sludge
Rotating discs
Fig 9.11 Exotic anaerobic filter processes. Normally used without final settling. The height of
the filter layer in the fluidized filter is controlled by withdrawal of filter grains (not
shown in the figure) which are returned in the column after the treatment. The treated
sludge can be treated separately or be mixed in the treated flow of water.
294