? Systems require a larger amount of space and
tankage than other "higher rate" processes,
which have shorter aeration detention times.
Sequencing batch reactors
Advantages
? SBRs can consistently perform nitrification as
well as denitrification and phosphorous removal.
? SBRs have large operational flexibility.
? The ability to control substrate tension within
the system allows for optimization of treatment
efficiency and control over nitrogen removal,
filamentous organisms, and the overall stability
of the process.
? Since all the unit processes are operated in a
single tank, there is no need to optimize aeration
and decanting to comply with power
requirements and lower decant discharge rates.
? Sludge bulking is not a problem.
? Significant reductions in nitrate nitrogen can
occur by incorporating an anoxic cycle in the
system.
? SBRs have little operation and maintenance
problems.
? Systems require less space than extended
aeration plants of equal capacity.
? SBRs can be manned part time from remote
locations, and operational changes can be made
easily.
? The system allows for automatic and positive
control of mixed liquor suspended solids
(MLSS) concentration and solids retention time
(SRT) through the use of sludge wasting.
Disadvantages
? It is hard to adjust the cycle times for small
communities.