(a) A wastewater treatment facility must be designed to prevent the discharge of untreated or partially treated wastewater during electrical power outages.
(b) A wastewater treatment facility must include an audiovisual alarm system. The alarm system must transmit all alarm conditions through the use of an auto-dialer system, a Supervisory Control and Data Acquisition (SCADA) system, or a telemetering system connected to a continuously monitored location. Audiovisual alarms are not required if the SCADA system notifies the operator about communication loss, in addition to all other alarm conditions.
(c) An alarm system must self-activate if:
(1) the power supply is interrupted;
(2) a pump fails; or
(3) a high water level alarm is triggered.
(d) An alarm system must include self-testing capability at the control panel.
(e) An owner shall determine the reliability of the existing commercial power service for a wastewater treatment facility using records from the past 60 consecutive months from the electric utility that serves the wastewater treatment facility. The entire record must be used if 60 months of records are not available. The owner must provide the power outage records and the reliability determination in the engineering report. The records must:
(1) be in writing;
(2) be on the electric utility's letterhead and bear a signature of an electric utility employee who has knowledge of data about power outages;
(3) identify the location of the wastewater treatment facility;
(4) list the total number of power outages that have occurred during the past 60 consecutive months; and
(5) indicate the date and duration of each recorded power outage.
(f) The executive director may consider documentation of commercial power system upgrades and their effects on the reliability of commercial power. Documentation of upgrades and their effects on power reliability must be submitted to the executive director in writing on the electric utility's letterhead and must bear the signature of an electric utility employee.
(g) Systems for preventing discharge of untreated or partially treated wastewater must operate for a duration at least equal to the longest power outage on record for the past 60 consecutive months, or at least 20 minutes, whichever is longer. The design must consider the effects of peak flow, inflow, and infiltration. If the longest power outage on record for the past 60 consecutive months is greater than 48 hours and generators will be used to provide backup power, then the owner must have a contract in place that guarantees fuel supply during an emergency. The owner must also have sufficient storage capacity at the wastewater treatment facility for the fuel for the duration of the emergency.
(h) Systems for preventing discharge of untreated or partially treated wastewater at a wastewater treatment facility must either be permanent features of the wastewater treatment facility, or be temporary power systems that are capable of being made operational before an unauthorized discharge occurs during any electrical power outage. The engineer must describe how a temporary power system will be deployed and operated in the engineering report, and must address deployment during all types of weather events that might reasonably cause a power outage at the wastewater treatment facility.
(i) Systems for preventing discharge of untreated or partially treated wastewater may include any combination of alternate power sources, on-site generators, interceptor systems, on-site retention, collection system storage, portable generators, mechanical backup systems, or other similar systems.
(1) Collection system storage may not be used as a sole means of preventing the discharge of untreated or partially treated wastewater during a power outage.
(2) The main power source and an alternate power source may not be provided by the same power plant.
(3) Portable generators and pumps may only be used to guarantee service if:
(j) The engineering report must include a description of emergency operation of the wastewater treatment facility. Treatment units that require continuous operation during a power outage must be identified in the engineering report. The minimum requirements for the systems that must be operational and additional engineering report requirements are listed in paragraphs (1) - (4) of this subsection.
(1) A wastewater treatment facility must be designed to achieve primary treatment and to disinfect the wastewater to ensure compliance with the bacteria limits established in the wastewater treatment facility's wastewater permit during all power outages, including outages that are longer than outage predicted based on the power reliability determination required in subsection (e) of this section.
(2) All components of the disinfection system, including any reclaimed water used to make a chemical solution, must operate at full capacity during all power outages according to the requirements of §217.37 of the title (relating to Disinfection System Power Reliability), including outages that are longer than outage predicted based on the power reliability determination required in subsection (e) of this section.
(3) Return activated sludge pumps must be operational during any power outage.
(4) If portable generators or pumps are used to guarantee service, the engineering report must include:
Source Note: The provisions of this §217.36 adopted to be effective December 4, 2015, 40 TexReg 8254