Section 58.01.16.440 - FACILITY AND DESIGN STANDARDS FOR MUNICIPAL WASTEWATER TREATMENT OR DISPOSAL FACILITIES: WASTEWATER PUMPING STATIONS01.General. Section 440 regulates both public and private municipal wastewater collection pump stations and does not regulate individual residence pump stations, individual residence grinder pump stations, or individual residence septic tank effluent pump stations. See Section 441 for regulation of those types of pump stations.a. Flooding. Wastewater pumping station structures and electrical and mechanical equipment shall be protected from physical damage by the one hundred (100) year flood. Wastewater pumping stations shall remain fully operational and accessible during the twenty-five (25) year flood. Regulations of state and federal agencies regarding flood plain obstructions shall be considered.b. Accessibility and Security. The pumping station shall be accessible by maintenance vehicles during all weather conditions.c. Grit. The wet well and pump station piping shall be designed to avoid operational problems from the accumulation of grit.d. Safety. Provisions shall be made to consider the protection of maintenance personnel and visitors from typical and foreseeable hazards in accordance with the engineering standards of care. See also Subsection 450.07.02.Design. Design of wastewater pumping stations shall meet the applicable requirements of Subsections 440.02.a. through 440.02.i.a. Type. Wastewater pumping stations in general use fall into four types: wet well/dry well, submersible, suction lift, and screw pump.b. Structures. i. Separation. Dry wells shall be completely separated from the wet well. Common walls must be gas tight.ii. Equipment Removal. Provision shall be made to facilitate removing pumps, motors, and other mechanical and electrical equipment. Individual pump and motor removal must not interfere with the continued operation of remaining pumps.iii. Access and Safety Landings. (1) Access. Suitable means of access for maintenance personnel wearing self-contained breathing apparatus shall be provided to dry wells and to wet wells. See also Subsection 450.07.(2) Safety Landings. Section 009 provides a reference to requirements of the Occupational Safety and Health Administration (OSHA), compliance with which may be required by other law.iv. Buoyancy. Where high groundwater conditions are anticipated, buoyancy of the wastewater pumping station structures shall be considered and, if necessary, adequate provisions shall be made for protection.v. Construction Materials. Materials shall be selected that are appropriate under conditions of exposure to hydrogen sulfide and other corrosive gases, greases, oils, and other constituents frequently present in wastewater. This is particularly important in the selection of metals and paints.c. Pumps. i. Multiple Units. Multiple pumps shall be provided. Units shall have capacity such that, with any unit out of service, the remaining units will have capacity to handle the design peak hourly flow.ii. Protection Against Clogging. Pumps (except screw pumps) handling separate sanitary wastewater from thirty (30) inch or larger diameter sewers shall be protected by bar racks. Appropriate protection from clogging shall also be considered for small pumping stations.iii. Pump Openings. Pumps handling unscreened raw wastewater shall be capable of passing spheres of at least three (3) inches in diameter or be a grinder pump.iv. Priming. The pump shall be placed so that, under normal operating conditions, it will operate under a positive suction head, except as specified in Subsection 440.03.v. Electrical Equipment. Section 009 provides a reference to the requirements of the National Electrical Code, compliance with which may be required by other law.vi. Intake. Section 008 provides a reference to the American National Standard Institute/Hydraulic Institute ANSI/HI 9.8, American National Standard for Centrifugal and Vertical Pump Intake Design.vii. Dry Well Dewatering. Dry wells shall be equipped with a positive means for dewatering.viii. Pumping Rates. The pumps and controls of main pumping stations shall be selected to operate with varying rates. The pump control system design shall take into account, and minimize as needed, downstream impact of pump discharge hydraulic surges. The station design capacity shall be based on peak hourly flow as determined in accordance with Section 411 and shall be adequate to maintain a velocity in the force main sufficient to avoid solids deposition. See Subsection 440.09.d. Controls. Water level control sensing devices shall be designed to allow for automatic control of pumps.e. Valves. i. Suction Line. Suitable shutoff valves shall be placed on the suction lines of dry pit pumps.ii. Discharge Line. Suitable shutoff and check valves shall be placed on the discharge line of each pump (except on screw pumps). The check valve shall be located between the shutoff valve and the pump. Check valves shall be suitable for the material being handled and shall be placed on the horizontal portion of the discharge piping except for ball checks, which may be placed in the vertical run. Valves shall be capable of withstanding normal pressure and water hammer. All shutoff and check valves shall be operable from the floor level and accessible for maintenance. Outside levers are recommended on swing check valves.f. Wet Wells. i. Section 008 provides a reference to the American National Standard Institute/Hydraulic Institute ANSI/HI 9.8, American National Standard for Centrifugal and Vertical Pump Intake Design as a guidance document.ii. Air Displacement. Covered wet wells shall have provisions for air displacement to the atmosphere, such as an inverted "j" tube or other means.g. Safety Ventilation. Adequate ventilation shall be provided for all pump stations unless access is provided using confined space entry procedures. Where the dry well is below the ground surface, mechanical ventilation is required. If screens or mechanical equipment requiring maintenance or inspection are located in the wet well, permanently installed ventilation is required. There shall be no interconnection between the wet well and dry well ventilation systems. Section 008 provides a reference to guidance documents; see Subsection 008.11.h. Flow Measurement. Suitable methods for measuring wastewater flow shall be addressed at all pumping stations.i. Water Supply. There shall be no physical connection between any potable water supply and a wastewater pumping station which, under any conditions, might cause contamination of the potable water supply. If a potable water supply connection is made to the station, the connection shall comply with IDAPA 58.01.08, "Idaho Rules for Public Drinking Water Systems."03.Suction Lift Pump Stations - Special Considerations. Suction lift pumps shall meet the applicable requirements of Subsection 440.02. a. Pump Priming and Lift Requirements. Suction lift pumps shall be of the self-priming or vacuum-priming type. Suction lift pump stations using dynamic suction lifts exceeding the limits outlined in Subsections 440.03.b. through 440.03.d. may be approved upon submission of factory certification of pump performance and detailed calculations indicating satisfactory performance under the proposed operating conditions.b. Self-Priming Pumps. Self-priming pumps shall be capable of rapid priming and re-priming at the "lead pump on" elevation. Such self-priming and re-priming shall be accomplished automatically under design operating conditions.c. Vacuum-Priming Pumps. Vacuum-priming pump stations shall be equipped with dual vacuum pumps capable of automatically and completely removing air from the suction lift pump. The vacuum pumps shall be adequately protected from damage due to wastewater. The combined total of dynamic suction lift at the "pump off" elevation and required net positive suction head at design operating conditions shall not exceed twenty-two (22) feet.d. Equipment, Wet Well Access, and Valving Location. The pump equipment compartment shall be above grade or offset and shall be effectively isolated from the wet well to prevent a hazardous and corrosive sewer atmosphere from entering the equipment compartment. Wet well access shall not be through the equipment compartment and shall be at least twenty-four (24) inches in diameter. Gasketed replacement plates shall be provided to cover the opening to the wet well for pump units removed for servicing. Valving shall not be located in the wet well.04.Submersible Pump Stations - Special Considerations. Submersible pump stations shall meet the applicable requirements of Subsection 440.02, except as modified in Subsection 440.04. a. Construction. Submersible pumps and motors shall be designed specifically for raw wastewater use, including totally submerged operation during a portion of each pumping cycle. An effective method to detect shaft seal failure or potential seal failure shall be provided.b. Pump Removal. Submersible pumps shall be readily removable and replaceable without personnel entering or dewatering the wet well, or disconnecting any piping in the wet well.c. Electrical Equipment. Section 009 provides a reference to the requirements of the National Electrical Code, compliance with which may be required by other law. i. Power Supply and Control Circuitry. Electrical supply, control, and alarm circuits shall be designed to provide strain relief and to allow disconnection from outside the wet well. Terminals and connectors shall be protected from corrosion by location outside the wet well or through use of watertight seals.ii. Controls. The motor control center shall be located outside the wet well, be readily accessible, and be protected by a conduit seal or other appropriate measures to prevent the atmosphere of the wet well from gaining access to the control center. The seal shall be located so that the motor may be removed and electrically disconnected without disturbing the seal. When such equipment is exposed to weather, it is recommended that it meet the requirements of weatherproof equipment NEMA 3R or 4.iii. Power Cord. Pump motor power cords shall be designed for flexibility and serviceability under conditions of extra hard usage. Ground fault interruption protection shall be used to de-energize the circuit in the event of any failure in the electrical integrity of the cable. Power cord terminal fittings shall be corrosion-resistant and constructed in a manner to prevent the entry of moisture into the cable, shall be provided with strain relief appurtenances, and shall be designed to facilitate field connecting.d. Valves. Valves required under Subsection 440.02 shall be located in a separate valve chamber. Provisions shall be made to remove or drain accumulated water from the valve chamber. The valve chamber may be dewatered to the wet well through a drain line with a gas and water tight valve. Check valves that are integral to the pump need not be located in a separate valve chamber provided that the valve can be removed from the wet well in accordance with Subsection 440.04. Access shall be provided in accordance with Subsection 440.02.05.Screw Pump Stations - Special Considerations. Screw pump stations shall meet the applicable requirements of Subsection 440.02.a. Covers. Covers or other means of excluding direct sunlight shall be provided as necessary to eliminate adverse effects from temperature changes.b. Pump Wells. A positive means of isolating individual screw pump wells shall be provided.c. Bearings. Submerged bearings shall be lubricated by an automated system without pump well dewatering.06.Alarm Systems. Alarm systems with a backup power source shall be provided for pumping stations. The alarm shall be activated in cases of power failure, dry well sump and wet well high water levels, pump failure, unauthorized entry, or other cause of pump station malfunction. Pumping station alarms, including identification of the alarm condition, shall be transmitted to a twenty-four (24) hour response center. Audio-visual alarm systems may be acceptable in some cases in lieu of a transmitting system depending upon location, station holding capacity, and inspection frequency.07.Emergency Operation. a. Objective. The objective of emergency operation is to prevent the unintended discharge of raw or partially treated wastewater to any waters or land surface and to protect public health by preventing back up of wastewater and subsequent discharge to basements, streets, and other public and private property.b. Emergency Pumping Capability. Emergency pumping capability is required for all new lift stations constructed after April 15, 2007. Emergency pumping capability is required for all existing lift stations that undergo a material modification or expansion unless overall system reliability can be proven adequate to the Department as shown in Subsections 440.07.b.i. and 440.07.b.ii. or overflow prevention is provided by adequate emergency storage capacity as defined in these rules. If required, emergency pumping capability shall be accomplished by connection of the station to at least two (2) independent utility substations as determined by and stated in a letter from the appropriate power provider, by provision of portable or in-place internal combustion engine equipment which will generate electrical or mechanical energy, or by the provision of portable pumping equipment. Such emergency standby systems shall have sufficient capacity to start up and maintain the total rated running capacity of the station. Regardless of the type of emergency standby system provided, a portable pump connection to the force main with rapid connection capabilities and appropriate valving shall be provided outside the dry well and wet well.i. System reliability is considered adequate if power grid outages average three (3) or less per year based on data for the three (3) previous years with no more than six (6) outages in a single year.ii. Outage duration averages less than four (4) hours based on data for the three (3) previous years, with not more than one (1) outage during the three (3) previous year period exceeding eight (8) hours. Power loss for at least thirty (30) minutes qualifies as an outage.c. Equipment Requirements.i. General. The following general requirements shall apply to all internal combustion engines used to drive auxiliary pumps, service pumps through special drives, or electrical generating equipment:(1) Engine Protection. The engine must be protected from operating conditions that would result in damage to equipment. Unless continuous manual supervision is planned, protective equipment shall be capable of shutting down the engine and activating an alarm on site and as provided in Subsection 440.06. Protective equipment shall monitor for conditions of low oil pressure and overheating, except that oil pressure monitoring will not be required for engines with splash lubrication.(2) Size. The engine shall have adequate rated power to start and continuously operate under all connected loads.(3) Fuel Type. Reliability and ease of starting, especially during cold weather conditions, shall be addressed in the selection of the type of fuel.(4) Fuel Storage. Fuel storage and piping facilities if provided shall be constructed in accordance with applicable state and federal regulations.(5) Engine Ventilation. The engine shall have adequate ventilation of fuel vapors and exhaust gases.(6) Routine Start-up. All emergency equipment shall be provided with instructions indicating the need for regular starting and running of such units at full loads.(7) Protection of Equipment. Emergency equipment shall be protected from damage at the restoration of regular electrical power.ii. Engine-Driven Pumping Equipment. Where permanently-installed or portable engine-driven pumps are used, the following requirements in addition to general requirements shall apply. (1) Pumping Capacity. Engine-driven pumps shall meet the design pumping requirements unless storage capacity is available for flows in excess of pump capacity. Pumps shall be designed for anticipated operating conditions, including suction lift if applicable.(2) Operation. The engine and pump shall be equipped to provide automatic start-up and operation of pumping equipment unless manual start-up and operation is justified. Provisions shall also be made for manual start-up. Where manual start-up and operation is justified, storage capacity and alarm system must meet the requirements of Subsection 440.07.c.ii(3).(3) Portable Pumping Equipment. Where part or all of the engine-driven pumping equipment is portable, adequate emergency storage capacity with alarm system shall be provided to allow time for detection of pump station failure and transportation and hookup of the portable equipment.iii. Engine-Driven Generating Equipment. Where permanently-installed or portable engine-driven generating equipment is used, the following requirements shall apply in addition to the general requirements of Subsection 440.07.(1) Generating Capacity.(a) Generating unit size shall be adequate to provide power for pump motor starting current and for lighting, ventilation, and other auxiliary equipment necessary for safety and proper operation of the lift station.(b) The operation of only one pump during periods of auxiliary power supply must be justified. Such justification may be made on the basis of the design peak hourly flows relative to single-pump capacity, anticipated length of power outage, and storage capacity.(c) Manual or special sequencing controls shall be provided to start pump motors unless the generating equipment has capacity to start all pumps simultaneously with auxiliary equipment operating.(2) Operation. Provisions shall be made for automatic and manual startup and load transfer unless only manual start-up and operation is justified. Automatic transfer switches shall be UL listed and meet NEC requirements. The generator must be protected from operating conditions that would result in damage to equipment. Provisions shall be made to allow the engine to start and stabilize at operating speed before assuming the load. Where manual start-up and transfer is justified, storage capacity and alarm system must meet the requirements of Subsection 440.07.c.iii.(3).(3) Portable Generating Equipment. Where portable generating equipment and manual transfer is provided, adequate emergency storage capacity with alarm system shall be provided to allow time for detection of pump station failure and transportation and connection of generating equipment. Special electrical connections and double throw switches shall be provided for connecting portable generating equipment. Manual transfer switches shall be UL listed and meet NEC requirements.iv. Independent Utility Substations. Where independent substations are used for emergency power, each separate substation and its associated transmission lines shall be capable of starting and operating the pump station at its rated capacity.08.Instructions and Equipment. Wastewater pumping stations and portable equipment shall be supplied with a complete set of operational instructions, including emergency procedures, maintenance schedules, tools, and such spare parts as may be necessary.09.Operation and Maintenance. a. An operation and maintenance manual shall be submitted to and approved by the Department as required by Section 425. Adherence to the terms of this approved manual shall be required. The owner shall be responsible for maintaining the wastewater facility in a manner that assures its designed operation.b. For private municipal wastewater collection pump stations, documents that detail the technical, managerial, and financial capabilities of the private entity to properly operate and maintain said pump station for the long term shall be submitted to the Department for approval prior to operation.10.Force Mains. a. Velocity and Diameter. At design pumping rates, a cleansing velocity of at least two (2) feet per second shall be maintained.b. Air and Vacuum Relief Valve. An air relief valve shall be placed at high points in the force main to prevent air locking. The force main configuration and head conditions shall be evaluated as to the need for and placement of vacuum relief valves.c. Termination. The force mains from other than individual grinder pump stations shall enter a receiving manhole. Corrosion protection for the receiving manhole shall be provided. Control of odors at such discharge points shall be evaluated.d. Pipe and Design Pressure. Pipe and joints shall be equal to water main strength materials suitable for design conditions. The force main, reaction blocking, thrust restraint, and station piping shall be designed to withstand water hammer pressures and associated cyclic reversal of stresses that are expected with the cycling of wastewater lift stations. The use of surge valves, surge tanks, or other suitable means to protect the force main against severe pressure changes shall be evaluated.e. Special Construction. Force main construction near streams or water works structures and at water main crossings shall meet applicable provisions of Section 430.f. Design Friction Losses. i. Friction Coefficient. Friction losses through force mains shall be based on the Hazen and Williams formula or other acceptable methods. When the Hazen and Williams formula is used, the friction losses for varying values of "C" shall be evaluated for different types and ages of pipe.ii. Maximum Power Requirements. When initially installed, force mains will have a significantly higher "C" factor. The effect of the higher "C" factor shall be considered in calculating maximum power requirements and duty cycle time to prevent damage to the motor. The effects of higher discharge rates on selected pumps and downstream facilities shall also be considered.g. Identification. Where force mains are constructed of material which might cause the force main to be confused with potable water mains, the force main shall be appropriately identified using trench tape saying "raw sewage," "biohazard," or other appropriate wording.h. Leakage Testing. Leakage tests shall be specified including testing methods and leakage limits. Testing shall conform with Sections 401.3.6 and 505.3.3 of the "Idaho Standards for Public Works Construction," incorporated by reference into these rules at Section 004.i. Thrust Blocking or Restraint. Thrust blocking or restraint shall conform with Sections 401.3.4 of the "Idaho Standards for Public Works Construction," incorporated by reference into these rules at Section 004, or specific calculations reviewed and approved by the Department.j. Maintenance Considerations. Isolation valves shall be used if force mains connect into a common force main.k. Cover. Force mains shall be covered with sufficient earth or other insulation to prevent freezing or other physical damage.Idaho Admin. Code r. 58.01.16.440