30 Tex. Admin. Code § 217.190

Current through Reg. 49, No. 45; November 8, 2024
Section 217.190 - Filtration
(a) Reasons for Use.
(1) Permit Requirements. A wastewater treatment facility that requires tertiary effluent limitations must use filtration as a unit of operation to supplement suspended solids removal. Tertiary effluent limits are any limits less than or equal to five milligrams per liter for five-day biochemical oxygen demand or total suspended solids.
(2) Specific Water Quality Requirements. A wastewater treatment facility designed for secondary or advanced secondary treatment effluent limitations may use filtration as a unit of operation to supplement suspended biological floc removal. Filters may be designed for intermittent operation if filters are not necessary to meet permitted effluent limitations.
(b) Redundancy.
(1) A wastewater treatment facility using filtration to provide tertiary treatment to comply with a permit requirement must have a minimum of two independent, fully functional filter basins with independent, fully functional equipment.
(2) The design of a filtration system must specify the submerged filter surface area required to treat the peak flow with the largest filter unit out of service.
(3) If a filter is provided solely to polish wastewater in situations where permit compliance does not depend on the use of a filter, such as in some cases of reclaimed water use, one filter is allowed.
(c) Source of Backwash Water. A filtration system must use filtered effluent as the source of backwash water.
(d) Disposition of Backwash Water. A filtration system must return backwash water containing material cleaned from a filter to the headworks of the wastewater treatment facility or to the influent lift station for processing.
(e) Sequence of Treatment Units.
(1) A final clarifier must precede a filter.
(2) A filter system may be used in conjunction with a disinfection tank to provide additional detention time, provided the filter is backwashed to the headworks of the wastewater treatment facility or to the influent lift station.
(f) Overload Conditions. A design must prevent effluent or partially treated effluent from overflowing from any filtration unit.
(g) Control of Slime Growth. A filtration system must provide periodic disinfectant in the influent stream to control slime growth in the filter and backwash storage tank.

30 Tex. Admin. Code § 217.190

The provisions of this §217.190 adopted to be effective August 28, 2008, 33 TexReg 6843; Amended by Texas Register, Volume 40, Number 47, November 20, 2015, TexReg 8324, eff. 12/4/2015