Liquid Phase Anaerobic Processes
In this section we are discussing anaerobic processes which are carried out essentially in the liquid. Solid wastes can be treated by many of these processes if the wastes are processed at the inlet to become a slurry with liquid properties.
Anaerobic Suspended Growth Processes
The anaerobic sludge digestors which were installed in sewage treatment works from the early part of the twentieth century, were suspended growth processes. Many plants continue to be based on such processes, however, the following recognised variants have subsequently been designed, and as no one solution excels under all circumstances, each must be considered to be a part of the AD process toolbox:-
- complete mix anaerobic process
- anaerobic contact process
- anaerobic Sequencing Batch Reactor (ASBR).
Generic formula are available in the texts published to enable the production of process designs for each of the above.
Anaerobic Sludge Blanket Processes
These are suspended growth processes of a special type. The USAB process is the best known proprietary process which uses an anaerobic sludge blanket, and over 500 have been built, mostly for water treatment. The main variants are:-
Generic formula are available in the texts published to enable the production of process designs for each of the above.
Fluidized-bed Attached Growth Processes
These include the:-
- anaerobic expanded-bed reactor (AEBR) which is only partially fluidised
- anaerobic fluidised bed reactor.
Downflow Attached Growth Processes
These are anaerobic filters and include trickling type filters in which any one of a wide range of packing materials have been used.
Other Anaerobic Treatment Processes
These include:-
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