- (a) Sequencing batch reactor (SBR) design shall be based on experience at comparable facilities and meet the applicable requirements of Env-Wq 713.01 through Env-Wq 713.05 except as modified in this section.
- (b) SBRs shall be designed and constructed to allow for static fill, mixed fill, and aerated fill to allow for operational flexibility.
(c) More than 2 tanks shall be provided, unless one of the following is provided:
- (1) An influent flow equalization tank sized to hold a minimum of 2 design capacity decantable volumes; or
- (2) Provisions to allow SBR tanks to operate in a continuous flow-through mode during emergency operations.
- (d) System sizing shall be based on aerated SRT.
- (e) System reliability with any single SBR tank out of service and the instantaneous flow delivery shall be evaluated in the design of decanter weirs and approach velocities.
- (f) The decanter shall not create a vortex or take in floatables or sludge.
- (g) Scum removal shall be provided.
- (h) The SBR design shall include in-place dewatering capability and provisions for transferring mixed liquor between the SBR tanks.
- (i) Each SBR tank shall be capable of wasting sludge during each cycle.
- (j) If blowers are provided, blowers shall meet the requirements of Env-Wq 713.02 through 713.05.
- (k) Mechanical mixing independent of aeration shall be provided for all systems where biological phosphorous removal or denitrification is required, with mixing equipment sized to thoroughly mix the entire basin from a settled condition within 3 minutes without aeration.
(l) Post-SBR tank flow equalization shall be provided to equalize flow variations and designed to meet the following criteria:
- (1) Hold a minimum of one design capacity decantable volume;
- (2) Provide a means to return the decanted effluent to the headworks for additional treatment; and
- (3) Provide a means to remove solids from the tank bottom.
- (m) An automatic process control having an uninterruptible power supply with electrical surge protection shall be provided.
- (n) Manual override shall be provided in addition to automatic process control. Both automatic and manual controls shall allow independent operation of each tank.
- (o) Controls shall allow at least 20 minutes of settling between the react and decant phases.
Source. (See Revision Note at chapter heading for Env-Wq 700) #8590, eff 3-25-06; ss by #10693, eff 10-15-14; ss by #14258, eff 7-1-25, EXPIRES: 7-1-35