Section 604.1335  Treatment Plant Storage

Treatment plant storage must meet the following requirements.

a)         Clearwell storage must:

1)         provide contact time, when required, under Section 604.715;

2)         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)         be sized in conjunction with distribution system storage, to relieve the filters from having to follow fluctuations in water use;

4)         provide an overflow and vent; and

5)         provide a minimum of two clearwells or clearwell compartments.

b)         Single wall separation of raw and treated water is prohibited.

c)         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)         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.