reglab/statecodes huggingface dataset:
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter E - PRELIMINARY TREATMENT UNITS › Section 217.125 - Grit Chambers

Current through Reg. 49, No. 28; July 12, 2024
(a) Horizontal Flow
				  Grit Chambers.
(1) Velocity through a
				  horizontal flow grit chamber must range from 0.8 feet per second to no more
				  than 1.3 feet per second.
(2) A
				  horizontal flow grit chamber channel must minimize turbulence and provide
				  uniform velocity across the channel.
(3) The channel size of a horizontal flow
				  grit chamber must accommodate the grit removal equipment capacity and grit
				  storage.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter E - PRELIMINARY TREATMENT UNITS › Section 217.126 - Grit Handling

Current through Reg. 49, No. 28; July 12, 2024
(a) A grit washing
				  unit or grit storage area must be designed to return recycled water and
				  drainage to the headworks of the wastewater treatment facility.
(b) A grit chamber located below ground level
				  must include mechanical grit handling equipment.
(c) Grit must be stored in a container with a
				  tight-fitting cover and must be managed and disposed of in accordance with
				  §
										217.123
				  of this title (relating to Screenings and Debris Handling).
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter E - PRELIMINARY TREATMENT UNITS › Section 217.127 - Pre-aeration Units

Current through Reg. 49, No. 28; July 12, 2024
(a) Pre-aeration
				  units may be used at a wastewater treatment facility to:
(1) control odor;
(2) reduce septicity;
(3) separate grease; or
(4) promote uniform distribution of solids to
				  clarifiers.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter E - PRELIMINARY TREATMENT UNITS › Section 217.128 - Flow Equalization Basins

Current through Reg. 49, No. 28; July 12, 2024
(a) A
				  wastewater treatment facility must be designed with a flow equalization basin
				  if:
(1) the total daily influent flow volume
				  or total daily influent organic loading occurs during a period less than or
				  equal to ten hours; or
(2) the
				  wastewater treatment facility receives an influent flow of less than 10% of its
				  design flow or an influent organic loading less than 10% of its design organic
				  loading during a period of time equal to or greater than 48 hours in any period
				  of seven consecutive days.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter E - PRELIMINARY TREATMENT UNITS › Section 217.129 - Primary Clarifiers

Current through Reg. 49, No. 28; July 12, 2024
(a) Inlets.
(1) A primary clarifier inlet must provide
				  uniform flow and stilling.
(2)
				  Vertical flow velocity through an inlet stilling well must not exceed 0.15 feet
				  per second at peak flow.
(3) An
				  inlet distribution channel must not have a dead-end corner and must prevent the
				  settling of solids in the channel.
(4) An inlet structure must allow floating
				  material to enter the clarifier.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.151 - Requirements for an Aeration Basin

Current through Reg. 49, No. 28; July 12, 2024
(a)
				  Unless designed for advanced nutrient removal, an aeration basin must be
				  designed to maintain a minimum dissolved oxygen concentration of 2.0 milligrams
				  per liter (mg/l) throughout the aeration basin at the maximum diurnal organic
				  loading rate determined in §217.32(a)(3) and Figure: 30 TAC §
										217.32(a)(3)
				  of this title (relating to Organic Loading and Flows for New Wastewater
				  Treatment Facilities).
(b) The
				  volume of aerated influent wastewater channels and aerated mixed liquor
				  transfer channels of an activated sludge system may be used to meet aeration
				  basin volume requirements, provided the activated sludge system uses aeration
				  by diffused air and the diffuser depth conforms to the requirements of §
										217.155(b)(5)(A)
				  of this title (relating to Aeration Equipment Sizing).
(c) The use of a contact stabilization system
				  for nitrification is prohibited.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.152 - Requirements for Clarifiers

Current through Reg. 49, No. 28; July 12, 2024
(a)
				  Inlets.
(1) A clarifier must have an inlet
				  valve or gate.
(2) A clarifier
				  inlet must provide uniform flow and stilling.
(3) A transfer pipe must not trap or entrain
				  air.
(4) Vertical flow velocity
				  through an inlet stilling well must not exceed 0.15 feet per second at peak
				  flow.
(5) An inlet distribution
				  channel must be designed to prevent the settling of solids in the
				  channel.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.153 - Requirements for Both Aeration Basins and Clarifiers

Current through Reg. 49, No. 28; July 12, 2024
(a) Construction. Construction material for
				  aeration basins and clarifiers must be resistant to the effects of a corrosive
				  wastewater environment.
(1) Aeration basins
				  and clarifiers must not be buoyant when empty.
(2) Structures using a common wall must be
				  designed to accommodate the stresses generated when one basin is full and an
				  adjacent basin is empty.
(3)
				  Aeration basin and clarifier walls must be watertight.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.154 - Aeration Basin and Clarifier Sizing-Traditional Design

Current through Reg. 49, No. 28; July 12, 2024
(a) This section applies to the traditional
				  approach for sizing an aeration basin and clarifier, and is based on
				  empirically-derived design values that have been used historically as standard
				  engineering practice.
(b) Aeration
				  Basin Sizing.
(1) An aeration system must be
				  designed to maintain a minimum dissolved oxygen concentration of 2.0 milligrams
				  per liter (mg/l) throughout the aeration basin at the maximum diurnal organic
				  loading rate determined in §217.32(a)(3) and Figure: 30 TAC §
											217.32(a)(3)
				  of this title (relating to Organic Loading and Flows for New Wastewater
				  Treatment Facilities). The executive director may consider alternative
				  dissolved oxygen specifications for designs that include biological nutrient
				  removal or tapered aeration for energy conservation, which must be approved in
				  writing.
(2) Based on the
				  calculated organic load, the aeration basin volume must be designed to ensure
				  that the organic loading on the aeration basin does not exceed the organic
				  loading rates in the following table:
Attached Graphic
(3) When identifying the aeration
				  basin temperature for the process design in Table F.1. in Figure: 30 TAC
				  §217.154(b)(2), the owner must use the average of the lowest consecutive
				  seven-day mean aeration basin temperature from a wastewater treatment facility
				  with similar characteristics. For purposes of this subsection, a similar
				  wastewater treatment facility:
(A) is located
				  within 50 miles of the wastewater treatment facility where the planned aeration
				  basin or system will be installed;
(B) uses the same placement of the aeration
				  basin (in-ground or above-ground); and
(C) has any other characteristics required by
				  the executive director in writing.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.155 - Aeration Equipment Sizing

Current through Reg. 49, No. 28; July 12, 2024
(a)
				  Oxygen Requirements (O2R) of Wastewater.
(1) An aeration system must be designed to
				  provide a minimum dissolved oxygen concentration in the aeration basin of 2.0
				  milligrams per liter (mg/l).
(2)
				  Mechanical and diffused aeration systems must supply the
				  O2R calculated by Equation F.2. in Figure: 30 TAC
				  §217.155(a)(3), or use the recommended values presented in Table F.3. in
				  Figure: 30 TAC §217.155(a)(3), whichever is greater.
(3) The O2R values in
				  Table F.3. in Figure: 30 TAC §217.155(a)(3) use concentrations of 200 mg/l
				  five-day biochemical oxygen demand (BOD 5) and 45 mg/l
				  ammonia-nitrogen (NH3-N) in Equation F.2. in Figure: 30 TAC
				  §217.155(a)(3):
Attached Graphic
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.156 - Sequencing Batch Reactors

Current through Reg. 49, No. 28; July 12, 2024
(a)
				  System Sizing and Reliability.
(1) A
				  sequencing batch reactor (SBR) must meet the reliability requirements in §
											217.155(b)
				  and (c)(3) of this title (relating to
				  Aeration Equipment Sizing), and power source reliability requirements in §
											217.36
				  of this title (relating to Emergency Power Requirements).
(2) An SBR must have a minimum decantable
				  volume that is sufficient to pass the design flow, and must be capable of
				  meeting permitted effluent limits, with the largest basin out of
				  service.
(3) A two-basin wastewater
				  treatment facility without removable aeration devices is required to have
				  aerated storage of mixed liquor separate from the SBR tank(s).
(4) An SBR with a fixed level decanter must
				  have more than two basins and additional decantable storage volume.
(5) An equalization basin is required if an
				  SBR has fixed decant equipment and decant volumes that do not accommodate the
				  peak flow.
(6) Organic loadings
				  must conform to the values in Table F.1. in Figure: 30 TAC §
											217.154(b)(2)
				  of this title (relating to Aeration Basin and Clarifier Sizing--Traditional
				  Design). Organic loadings must be below 35 pounds of five-day biochemical
				  oxygen demand per 1,000 cubic feet of tank volume.
(7) The reactor mixed liquor suspended solids
				  (MLSS) level at the normal operating level must range from at least 3,000
				  milligrams per liter (mg/l) to not more than 5,000 mg/l.
(8) The minimum depth of the MLSS during a
				  react phase is 9.0 feet.
(9) The
				  minimum side water depth of an SBR tank is 12 feet.
(10) An SBR must include sludge digestion
				  pursuant to the requirements in Subchapter J of this chapter (relating to
				  Sludge Processing).
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.157 - Membrane Bioreactor Systems

Current through Reg. 49, No. 28; July 12, 2024
(a)
				  Applicability.
(1) This section contains
				  criteria for low-pressure, vacuum, and gravity ultrafiltration or
				  microfiltration membrane bioreactors (MBRs).
(2) Other types of MBRs are considered
				  innovative technology and are subject to the requirements of §
											217.7(b)(2)
				  of this title (relating to Types of Plans and Specifications
				  Approvals).
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.158 - Solids Management

Current through Reg. 49, No. 28; July 12, 2024
(a) Solids
				  Recycling and Monitoring.
(1) A return sludge
				  system must operate as designed in all flow conditions.
(2) A monitoring and control system must
				  provide a means to control return and waste sludge flows from each clarifier,
				  to control return sludge flows into each aeration basin, to meter return sludge
				  flows, and to measure waste sludge flows.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.159 - Process Control

Current through Reg. 49, No. 28; July 12, 2024
(a) Solids
				  Retention Time Control.
(1) A wastewater
				  treatment facility design must include equipment for a wastewater treatment
				  facility operator to control the solids retention time (SRT) in the aeration
				  tanks by wasting a measured volume of surplus activated sludge.
(2) The engineering report and the operation
				  and maintenance manual must provide the formulas used for determining the
				  SRT.
(3) The SRT required for
				  nitrification applies to the aerobic portion of the wastewater treatment
				  facility.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.160 - Operability and Maintenance Requirements

Current through Reg. 49, No. 28; July 12, 2024
(a) All equipment must either be able to
				  operate at the temperature extremes of the wastewater treatment facility
				  location, or must be located in a temperature controlled enclosure.
(b) All equipment must be accessible for
				  inspection, maintenance, and operation.
(c) An enclosure that houses equipment must
				  have sufficient clearance and working room to safely remove and reinstall
				  equipment. The enclosure must be accessible to portable lifting devices or must
				  be equipped with overhead lifting eyes, hoists, trolleys, or cranes to
				  facilitate the safe removal of equipment.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.161 - Electrical and Instrumentation Systems

Current through Reg. 49, No. 28; July 12, 2024
(a) All three-phase motors must have phase
				  failure protection.
(b)
				  Instrumentation and monitoring equipment must have power surge
				  protection.
(c) A wastewater
				  treatment facility must conduct fault monitoring to notify the operator of high
				  wet well level, power interruption, disinfection failure, blower failure,
				  clarifier failure, return sludge pumping failure, and any other conditions that
				  the executive director may require an owner to monitor as a condition for
				  project approval.
(d) For a
				  wastewater treatment facility not staffed 24 hours per day, a telemetry with
				  battery back-up or supervisory control and data acquisition system with battery
				  backup must be able to notify an operator of a malfunction identified in
				  subsection (c) of this section within one minute of the malfunction.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.162 - Air Lift Pump Design

Current through Reg. 49, No. 28; July 12, 2024
(a)
				  Required Calculations.
(1) The engineering
				  report must include calculations to determine static and dynamic pressure head
				  necessary for operation of each air lift pump. Static and dynamic pressure head
				  requirements for the suction line must be considered in the
				  calculations.
(2) Air lift pump
				  systems must be designed to meet the range of required flow rates.
(3) The engineering report must include the
				  number of air lift pumps required and the minimum and maximum:
(A) design airflow rate for each air lift
				  pump;
(B) design flow rate for each
				  air lift pump; and
(C) design flow
				  rate for the system.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.163 - Advanced Nutrient Removal

Current through Reg. 49, No. 28; July 12, 2024
(a)
				  For a wastewater treatment facility designed to provide advanced nutrient
				  removal, the engineering report must specify the process units needed to
				  achieve the effluent limits established in the wastewater treatment facility's
				  wastewater permit.
(b) Biological
				  nutrient removal using an activated sludge process, membrane filtration, sand
				  filtration, or a combination of these processes may be used for advanced
				  nutrient removal without applying for the executive director's approval under
				  the innovative or non-conforming technology criteria in §
										217.7(b)(2)
				  of this title (relating to Types of Plans and Specifications Approvals). A
				  biological nutrient removal process that involves fixed-film treatment is
				  subject to the executive director's determination under §
										217.7(b)(2)
				  of this title.
(c) If a biological
				  nutrient removal unit is proposed, the engineering report must include the:
(1) anticipated food to microorganism ratio
				  in both the anoxic and anaerobic zones;
(2) volatile fatty acid recycle ratio;
				  and
(3) design of a foaming control
				  system.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter F - ACTIVATED SLUDGE SYSTEMS › Section 217.164 - Aeration Basin and Clarifier Sizing-Volume-Flux Design Method

Current through Reg. 49, No. 28; July 12, 2024
(a) A volume-flux
				  design must size an aeration basin and clarifier on the relationship between
				  the volume-flux of solids in the secondary clarifier, the sludge volume index
				  (SVI), and the sludge blanket depth. The following design approach may be used
				  as an alternative to the traditional design approach. If the volume-flux design
				  approach is used, it must be used consistently throughout the design. No other
				  design method may be used in combination with the volume-flux design method.
(1) A design may base the aeration tank
				  volume and the clarifier volume on a mixed liquor suspended solids (MLSS) and
				  floc volume (at SVI of 100) for the required minimum solids retention
				  time.
(2) Larger values of MLSS
				  require less aeration tank volume and greater clarifier volume.
(3) By examining a range of values of the
				  MLSS and the floc volume, the most favorable arrangement for a wastewater
				  treatment facility may be selected.
(4) When using the volume-flux design method,
				  the size of an aeration basin and a clarifier must be in accordance with the
				  requirements of this section.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.181 - Applicability

Current through Reg. 49, No. 28; July 12, 2024
This subchapter establishes the requirements for trickling
					 filters, rotating biological contactors, submerged biological contactors, and
					 filtration systems.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.182 - Trickling Filters-General Requirements

Current through Reg. 49, No. 28; July 12, 2024
(a) Trickling filters are classified
				  according to applied hydraulic loading, including recirculation, in million
				  gallons per day per acre of filter media surface area and influent organic
				  loadings in pounds of five-day biochemical oxygen demand
				  (BOD5) per day per 1,000 cubic feet of filter media. The
				  following factors must be used as the basis for the selection of the design
				  hydraulic and influent organic loadings:
(1)
				  BOD5 concentration of the influent wastewater;
(2) effectiveness of pretreatment;
(3) type of filter media; and
(4) treatment efficiency required.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.183 - Nitrifying Trickling Filters-Additional Requirements

Current through Reg. 49, No. 28; July 12, 2024
(a) Ventilation. A nitrifying trickling
				  filter must include forced ventilation to distribute airflow throughout the
				  underdrain area. The minimum design airflow rate must be the greater of:
(1) 50 pounds of oxygen provided per pound of
				  oxygen required at average organic loading, based on stoichiometry;
				  or
(2) 30 pounds of oxygen provided
				  per pound of oxygen required at peak organic loading, based on
				  stoichiometry.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.184 - Dual Treatment Using Trickling Filters

Current through Reg. 49, No. 28; July 12, 2024
(a) Classification. A trickling filter or
				  other attached-growth treatment unit in series with a suspended-growth process
				  is considered a dual treatment process that is classified as an Activated
				  Biological Filter (ABF) System, a Trickling Filter/Solids Contact (TF/SC)
				  System, a Roughing Filter/Activated Sludge (RF/AS) System, an Activated
				  Biological Filter/Activated Sludge (ABF/AS) System, or a Trickling
				  Filter/Activated Sludge (TF/AS) System.
(1)
				  ABF System. An ABF system consists of a tricking filter and a final clarifier.
				  An ABF system recirculates settled solids from the final clarifier through the
				  trickling filter with no separate aeration basin or solids contact
				  basin.
(2) TF/SC System. A TF/SC
				  system consists of a trickling filter sized to remove the majority of the
				  soluble five-day biochemical oxygen demand (BOD5),
				  followed by an aerated solids contact basin sized to provide polishing and
				  improved sludge settleability, followed by a final clarifier. A TF/SC system
				  recirculates activated sludge to a solids contact basin. The design of a TF/SC
				  system may include a sludge re-aeration basin.
(3) RF/AS System. An RF/AS system consists of
				  a trickling filter sized to perform primary treatment, followed by an aeration
				  basin sized to remove the majority of the soluble BOD5,
				  followed by a final clarifier. An RF/AS system circulates activated sludge to
				  the aeration basin.
(4) ABF/AS
				  System. An ABF/AS system consists of a trickling filter sized to perform
				  primary treatment, followed by an aeration basin sized to remove the majority
				  of the soluble BOD5, followed by a final clarifier. An
				  ABF/AS system recirculates activated sludge to the trickling filter.
(5) TF/AS System. A TF/AS system consists of
				  a trickling filter sized to perform roughing and concentration dampening,
				  followed by an intermediate clarifier, followed by an aeration basin sized to
				  remove the majority of the soluble BOD5, followed by a
				  final clarifier. A TF/AS system circulates activated sludge to the aeration
				  basin.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.185 - Rotating Biological Contactors

Current through Reg. 49, No. 28; July 12, 2024
(a)
				  Pretreatment.
(1) Pretreatment to remove
				  grit, debris, and excess oil and grease must precede a rotating biological
				  contactor (RBC). Grit, debris, and excess oil and grease must be handled and
				  disposed of in accordance with §
											217.123
				  and §
											217.126
				  of this title (relating to Screenings and Debris Handling; and Grit
				  Handling).
(2) The executive
				  director may require primary clarifiers, fine screens, or grit removal chambers
				  prior to an RBC to control high levels of grease, oil, grit, or other debris in
				  the influent waste stream.
(3)
				  Hydrogen sulfide concentration must be considered to determine whether an RBC
				  system requires pre-aeration.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.186 - Nitrifying Rotating Biological Contactors

Current through Reg. 49, No. 28; July 12, 2024
(a) A rotating biological contactor (RBC)
				  system designed for five-day biochemical oxygen demand
				  (BOD5) removal and nitrification of domestic wastewater
				  in a single system must include four stages and have a maximum overall organic
				  loading rate of 1.6 pounds of BOD5 per day per 1,000
				  square feet of media.
(b) A
				  nitrifying RBC must be designed to allow chemical addition if the influent pH
				  is below 7.0 standard units.
(c)
				  The engineering report must justify the nitrification rate of a system using
				  calculations.
(d) A nitrifying RBC
				  system may be subject to the requirements of §
										217.7(b)(2)
				  of this title (relating to Types of Plans and Specifications
				  Approvals).
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.187 - Dual Treatment Utilizing Rotating Biological Contactors

Current through Reg. 49, No. 28; July 12, 2024
(a) A rotating
				  biological contactor (RBC) may be used in conjunction with other treatment as a
				  dual treatment system.
(b) An RBC
				  may be used as a roughing unit, as described in §
										217.182(b)(1)
				  of this title (relating to Trickling Filters--General Requirements, regarding
				  trickling filter classifications), in series with an activated sludge
				  system.
(c) The engineering report
				  must include supporting data, calculations, process descriptions, and vendor
				  information to describe how a proposed RBC system will meet the permitted
				  effluent limitations.
(d) Combined
				  systems may be subject to the requirements of §
										217.7(b)(2)
				  of this title (relating to Types of Plans and Specifications
				  Approvals).
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.188 - Submerged Biological Contactor

Current through Reg. 49, No. 28; July 12, 2024
(a) A
				  submerged biological contactor (SBC) must be air driven and does not require a
				  cover. An SBC is any biological contactor where more than 60% of the surface is
				  below the water level at design flow.
(b) An SBC system requires the same
				  pretreatment as a rotating biological contactor system and must meet the
				  criteria in §
										217.185
				  of this title (relating to Rotating Biological Contactors), except as described
				  in paragraphs (1) and (2) of this subsection.
(1) Each SBC unit must include two air
				  headers - one to provide rotation of the unit, and one to provide dissolved
				  oxygen for biological activity.
(2)
				  Submerged bearings must be sealed to prevent intrusion of wastewater.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.189 - Dual Treatment Systems Using Submerged Biological Contactor

Current through Reg. 49, No. 28; July 12, 2024
(a) A submerged
				  biological contactor (SBC) may be used in conjunction with other treatment
				  systems.
(b) An SBC may be used as
				  a roughing unit, as described in §
										217.182(b)(1)
				  of this title (relating to Trickling Filters--General Requirements), in series
				  with activated sludge.
(c) SBC
				  units may be installed in existing activated sludge basins to create a
				  combination of fixed and suspended growth processes.
(d) If a dual treatment system employs an
				  SBC, the engineering report must include supporting data, calculations, process
				  descriptions, and vendor information to describe how the proposed dual
				  treatment system will provide the required treatment levels.
(e) These designs may be subject to the
				  requirements of §
										217.7(b)(2)
				  of this title (relating to Types of Plans and Specifications
				  Approvals).
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.190 - Filtration

Current through Reg. 49, No. 28; July 12, 2024
(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.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.191 - Additional Requirements for Deep Bed, Intermittently Backwashed, Granular Media Filters

Current through Reg. 49, No. 28; July 12, 2024
(a) Application
				  Rates. With one unit out of service, the peak application rate to any deep bed,
				  intermittently backwashed, granular media (deep bed) filtration unit must not
				  exceed twice the design application rate.
(1)
				  Single Media (Sand).
(A) The design
				  filtration rate for single media (sand) filters must not exceed three gallons
				  per minute per square foot (gpm/sf) of media surface.
(B) The maximum filtration run time between
				  backwash periods is 6.0 hours.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.192 - Additional Design Requirements for Multi-Compartmented, Low Head, Automatically Backwashed Filters

Current through Reg. 49, No. 28; July 12, 2024
(a) Application
				  Rates.
(1) With one unit out of service, the
				  peak application rate to any multi-compartmented, low head, automatically
				  backwashed (multi-compartmented) filter unit must not exceed twice the design
				  application rate.
(2) The
				  engineering report must include manufacturer's recommended filtration and
				  application rates with test data.
(3) Single Media. A single media
				  multi-compartmented filter must have a maximum design filtration rate of 3.0
				  gallons per minute per square foot of media surface.
(4) Dual Media. A dual media
				  multi-compartmented filter must have a maximum design filtration rate of 4.0
				  gallons per minute per square foot of media surface.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.193 - Cloth or Disk Filter Systems

Current through Reg. 49, No. 28; July 12, 2024
(a)
				  Cloth or disk filter systems must meet the requirements in §
										217.190 of
				  this title (relating to Filtration).
(b) Media Design.
(1) The average pore size of cloth or disk
				  filter media must not exceed 30 microns.
(2) The media thickness must be based on the
				  manufacturer's recommendations, considering frequent pressure changes. The
				  manufacturer's recommendations must be included in the engineering
				  report.
(3) The media must be
				  disinfectant-resistant if the filter will be exposed to
				  disinfectants.
(4) The media must
				  be chlorine-resistant if the filter will be exposed to chlorine.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter G - FIXED FILM AND FILTRATION UNITS › Section 217.194 - Alternative Designs for Effluent Polishing

Current through Reg. 49, No. 28; July 12, 2024
The executive director shall review alternative processes
					 for tertiary suspended solids removal, other than filters, as non-conforming
					 technologies subject to the requirements of §
										217.7(b)(2)
					 of this title (relating to Types of Plans and Specifications
					 Approvals).
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.201 - Applicability

Current through Reg. 49, No. 28; July 12, 2024
This subchapter establishes the minimum requirements for
					 Imhoff tanks, constructed wetlands, and all lagoons used to store treated,
					 untreated, or partially treated domestic wastewater, including facultative
					 lagoons, aerated and partially aerated lagoons, stabilization lagoons, raw
					 influent storage lagoons, treated effluent storage lagoons, evaporative lagoon
					 systems, and overland flow processes, except that lagoons used for reclaimed
					 water under Chapter 210 of this title (relating to Use of Reclaimed Water) must
					 comply with the requirements of that chapter.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.202 - Primary and Secondary Treatment Units

Current through Reg. 49, No. 28; July 12, 2024
(a) A primary treatment unit may be an
				  aerated lagoon, a partially aerated lagoon, a facultative lagoon, an
				  evaporative lagoon, or an Imhoff tank.
(b) A secondary treatment unit may be a
				  stabilization lagoon, a constructed wetland, an evaporative lagoon, or an
				  overland flow process. A secondary treatment unit may be used for polishing and
				  tertiary treatment.
(c) A treated
				  effluent storage lagoon downstream of the sampling location in the wastewater
				  treatment facility permit is not considered a treatment unit for the purposes
				  of this chapter.
(d) A secondary
				  treatment unit must be preceded by a primary treatment unit.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.203 - Design Criteria for Natural Treatment Units

Current through Reg. 49, No. 28; July 12, 2024
(a) This section applies to all earthen
				  lagoons and earthen treatment units in a wastewater treatment facility,
				  including constructed wetlands, facultative lagoons, aerated lagoons, partially
				  aerated lagoons, stabilization lagoons, evaporative lagoons, and storage
				  lagoons. Storage lagoons are considered treatment units for the purposes of
				  this chapter if they hold wastewater that is not final treated effluent, such
				  as raw influent or wastewater that has received intermediate
				  treatment.
(b) Flow Distribution.
The shape and size of a treatment unit must ensure uniform
					 distribution of the wastewater flow.
(c) Windbreaks and Screening.
(1) A windbreak or vegetative screening must
				  be used if operation of the treatment system could cause spray to drift off of
				  the property.
(2) The use, type,
				  and extent of windbreaks or vegetative screening must be approved in writing by
				  the executive director.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.204 - Imhoff Tanks

Current through Reg. 49, No. 28; July 12, 2024
(a) Settling
				  Compartment.
(1) The minimum length-to-width
				  ratio of a settling compartment is 2.0 to 1.0.
(2) A tank inlet must provide uniform flow
				  distribution across the width of a settling compartment.
(3) The septum walls must slope to the center
				  of a compartment at an angle of at least 50 degrees but not more than 60
				  degrees from horizontal. The septum walls must create an overlap with a
				  continuous slot that is at least 8.0 inches wide between the walls to allow
				  solids to be dispersed into the digestion compartment. To prevent gases from
				  escaping through the slot, one of the septum walls must continue past the slot
				  to create a slot overhang of at least 8.0 inches.
(4) The depth between the water level at
				  design flow and the plane of a slot must not be more than 9.0 feet.
(5) At least 18 inches of freeboard must be
				  provided above the normal water level.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.205 - Facultative Lagoons

Current through Reg. 49, No. 28; July 12, 2024
(a) Configuration,
				  Inlets, and Outlets.
(1) The length-to-width
				  ratio of a facultative lagoon must be 3.0 to 1.0.
(2) The flow in a facultative lagoon must be
				  from an inlet along one end of the lagoon to an outlet at the opposite end of
				  the lagoon.
(3) The length of a
				  facultative lagoon must be oriented in the direction of the prevailing winds
				  with the inlet side located such that debris will be blown toward the
				  inlet.
(4) A facultative lagoon
				  must have inlet baffles to collect floatable material when no pre-screening is
				  provided.
(5) An outlet must be
				  adjustable to allow the water level of a facultative lagoon to vary under
				  normal operating conditions.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.206 - Aerated Lagoons

Current through Reg. 49, No. 28; July 12, 2024
(a) The
				  requirements of this section apply to both completely mixed aerated lagoons and
				  partially mixed aerated lagoons, unless otherwise specified.
(b) A minimum of 1.6 pounds of oxygen per
				  pound of influent five-day biochemical oxygen demand
				  (BOD5) must be maintained in an aerated lagoon system,
				  even with the largest single aeration unit in a lagoon system out of
				  service.
(c) The aeration equipment
				  must have an audio-visual alarm system. If a wastewater treatment facility is
				  not staffed 24 hours per day, the alarm system must be connected to a telemetry
				  system, such as an auto dialer or Supervisory Control and Data Acquisition
				  system, with battery backup.
(d)
				  The BOD5 removal in each aerated lagoon must be
				  calculated using the following equation:
Attached Graphic
(1) The value of K for domestic wastewater in
				  a completely mixed lagoon is 0.50 day-1 at 20
				  degrees Celsius. The value of K for domestic wastewater in a partially mixed
				  lagoon is 0.28 day-1 at 20 degrees
				  Celsius.
(2) The value of K must be
				  adjusted for the minimum monthly water temperature using the following
				  equation:
Attached Graphic
(3) The value of K must be
				  determined for high-strength or industrial wastewater by either a laboratory
				  study or an evaluation of an existing wastewater treatment facility treating
				  wastewater with similar organic strength and industrial
				  contributions.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.207 - Stabilization Lagoons

Current through Reg. 49, No. 28; July 12, 2024
(a) Primary
				  treatment must remove the settleable and floatable solids in the influent prior
				  to the wastewater entering a stabilization lagoon.
(b) Odor Management.
(1) A stabilization lagoon must be located so
				  that odors from the stabilization lagoon will not cause a nuisance.
(2) If uncontaminated water is available, a
				  stabilization lagoon must be pre-filled with uncontaminated water to the 2.0
				  foot level at start-up.
(3) A
				  stabilization lagoon system must include a piping arrangement that allows the
				  recirculation of effluent from a final lagoon to the influent side of an
				  initial stabilization lagoon.
(4) A
				  stabilization lagoon may return recirculation water by surface spray to assist
				  in maintaining aerobic conditions at the lagoon surface and to reduce potential
				  odor.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.208 - Evaporative Lagoons

Current through Reg. 49, No. 28; July 12, 2024
(a) Design.
(1) If evaporative lagoons are used, the
				  wastewater treatment facility must have at least two evaporative
				  lagoons.
(2) The primary
				  evaporative lagoon must provide at least 60% of the total surface area of the
				  total evaporative lagoon system.
(3) The number and size of evaporative
				  lagoons must provide adequate evaporation for the design flow during periods of
				  low evaporation. For the purposes of this chapter, the low evaporation rate
				  used in design must be the lowest annual evaporation rate in the past 25 years
				  from the Texas Water Development Board's precipitation and lake evaporation
				  dataset for the quadrangle where the evaporation lagoon is located.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.209 - Constructed Wetlands

Current through Reg. 49, No. 28; July 12, 2024
(a) Types of
				  Constructed Wetlands. A constructed wetland may be either a free water surface
				  system or subsurface flow system.
(b) Natural Wetlands. The use of natural
				  wetlands for wastewater treatment is prohibited. For the purposes of this
				  chapter, a natural wetland is an area which was not constructed for wastewater
				  treatment that meets the definition of wetlands in 40 Code of Federal
				  Regulations, Part 230.
(c)
				  Constructed Wetland Design.
(1) A constructed
				  wetland must be preceded by primary treatment or secondary treatment.
(2) A primary treatment system that precedes
				  a constructed wetland must be designed to control odor and algae.
(3) A primary treatment system must produce
				  an effluent quality with no more than 150 milligrams per liter of five-day
				  biochemical oxygen demand to discourage anaerobic conditions and stress on
				  vegetative communities in any subsequent wetland treatment unit.
(4) A wastewater treatment facility that uses
				  a constructed wetland as the means of complying with a permit effluent limit
				  must be sized and designed to ensure that the permit limitations will be met
				  even when any one wetland cell is out of service. The engineering report must
				  include water balance calculations and the potential effect of evaporation on
				  the predicted effluent concentrations.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.210 - Constructed Wetlands-Free Water Surface Design

Current through Reg. 49, No. 28; July 12, 2024
(a) Areas of emergent vegetation in a free
				  water surface (FWS) wetland must have a maximum water depth less than or equal
				  to 24 inches at design flow.
(b)
				  Plants.
(1) Emergent plant spacing must be no
				  more than 66 inches on center.
(2)
				  If floating plants are used in a FWS wetland, the wetland must also contain
				  emergent plants.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.211 - Constructed Wetlands-Subsurface Flow System General Design

Current through Reg. 49, No. 28; July 12, 2024
(a) A wetted
				  subsurface media must allow adequate root penetration. The type of subsurface
				  media must be identified in the engineering report.
(b) The operational water depth of a
				  subsurface flow system (SFS) wetland must not exceed the lesser of:
(1) 18 inches at design flow; or
(2) the maximum normal root depth of the
				  emergent plant species used in the SFS wetland.
Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 217 - DESIGN CRITERIA FOR DOMESTIC WASTEWATER SYSTEMS › Subchapter H - NATURAL TREATMENT FACILITIES › Section 217.212 - Overland Flow Process

Current through Reg. 49, No. 28; July 12, 2024
(a) An overland
				  flow process is a non-conforming technology and is subject to the requirements
				  of §
										217.7(b)(2)
				  of this title (relating to Types of Plans and Specifications
				  Approvals).
(b) The distribution
				  system for an overland flow process must ensure uniform sheet flow of the
				  wastewater onto and across the overland flow terraces.