35 Ill. Adm. Code 604.1335
Treatment Plant Storage
Section 604.1335Â Treatment Plant Storage
Treatment plant storage must meet the following
requirements.
a)Â Â Â Â Â Â Â Â Clearwell
storage must:
1)Â Â Â Â Â Â Â Â provide
contact time, when required, under Section 604.715;
2)Â Â Â Â Â Â Â Â ensure
adequate disinfectant contact time by sizing the clearwell to include extra
volume to accommodate depletion of storage during the nighttime for
intermittently operated filtration plants with automatic high service pumping
from the clearwell during non-treatment hours;
3)Â Â Â Â Â Â Â Â be sized
in conjunction with distribution system storage, to relieve the filters from
having to follow fluctuations in water use;
4)Â Â Â Â Â Â Â Â provide
an overflow and vent; and
5)Â Â Â Â Â Â Â Â provide
a minimum of two clearwells or clearwell compartments.
b)Â Â Â Â Â Â Â Â Single
wall separation of raw and treated water is prohibited.
c)Â Â Â Â Â Â Â Â Other
treatment plant storage tanks/basins, including detention basins, backwash
reclaim tanks, receiving basins and pump wet wells for treated water, must be
designed as finished water storage structures, unless otherwise approved by the
Agency under Section 604.145(b).
d)Â Â Â Â Â Â Â Â When
provided, filter washwater tanks must be sized to provide adequate treated
water for the duration of the backwash cycle, including the sequential backwash
of several filters.