Section 58.01.16.450 - FACILITY AND DESIGN STANDARDS FOR MUNICIPAL WASTEWATER TREATMENT OR DISPOSAL FACILITIES: WASTEWATER TREATMENT FACILITIES: GENERAL01.Plant Location. a. General. The preliminary engineering report or facility plan shall include a detailed discussion for new facilities regarding site selection criteria and alternatives considered. See Sections 410 and 411.b. Flood protection. The treatment plant structures, electrical, and mechanical equipment shall be protected from physical damage by the one hundred (100) year flood. Treatment plants shall be designed to remain fully operational and accessible during the one hundred (100) year flood. This requirement applies to new construction and to existing facilities undergoing major modification. Local, state and federal flood plain regulations shall be considered.c. Setback distances. Facilities open to the atmosphere such as lagoons, open clarifiers, open aeration basins, and other such facilities shall be placed a minimum of two hundred (200) feet from residential property lines. If such open facilities are adjacent to property zoned as commercial or industrial, a lesser setback will be considered by the Department on a case by case basis. For totally enclosed facilities with noise and odor controls, the minimum setback shall be fifty (50) feet if approved by the Department. Neighboring property owners may grant long term easements or other types of legal documents tied to the land to allow for similar setbacks from future development or public use.02.Quality of Effluent. The required degree of wastewater treatment shall be based on the effluent requirements and water quality standards established by the responsible state agency and appropriate federal regulations including discharge permit requirements. Combined sewer overflows are not allowed.03.Design. a. Type of Treatment. The preliminary engineering report or facility plan shall include a detailed discussion regarding criteria and alternatives considered in selection of the appropriate type of treatment. See Sections 410 and 411. The plant design shall provide the necessary flexibility to perform satisfactorily within the expected range of waste characteristics and volumes.b. Required Engineering Data for New Process and Application Evaluation. The policy of the Department is to encourage rather than obstruct the development of any valid methods or equipment for treatment of wastewater. The lack of inclusion in these standards of some types of wastewater treatment processes or equipment should not be construed as precluding their use. The Department may approve other types of wastewater treatment processes and equipment that meet the performance standards set forth in these rules under the condition that the operational reliability and effectiveness of the process or device shall have been demonstrated under similar conditions with a suitably-sized unit operating at its design load conditions, to the extent required. To determine that such new processes and equipment or applications have a reasonable and substantial chance of success, the Department may require the following:i. Monitoring observations, including test results and engineering evaluations, demonstrating the efficiency of such processes.ii. Detailed description of the test methods.iii. Testing, including appropriately-composited samples, under various ranges of strength and flow rates (including diurnal variations) and waste temperatures over a sufficient length of time to demonstrate performance under climatic and other conditions which may be encountered in the area of the proposed installations.iv. Other appropriate information. The Department may require that appropriate testing be conducted and evaluations be made under the supervision of a competent process engineer other than those employed by the manufacturer or developer.c. Design period. The design period shall be clearly identified in the preliminary engineering report or facility plan as required in Sections 410 and 411.d. Design Loads. i. Hydraulic Design. (1) Critical Flow Conditions. Flow conditions critical to the design of the treatment plant shall be as described in the preliminary engineering report required by Section 411. Initial low flow conditions must be evaluated in the design to minimize operational problems with freezing, septicity, flow measurements and solids dropout. The appropriate design flows must be considered in evaluating unit processes, pumping, piping, etc.(2) Treatment Plant Design Capacity. The treatment plant design capacity shall be as described in Section 411. The plant design flow selected shall meet the appropriate effluent and water quality standards that are set forth in the discharge or other appropriate permit. For plants subject to high wet weather flows or overflow detention pump-back flows, the design maximum flows that the plant is to treat on a sustained basis shall be specified.(3) Flow Equalization. Facilities for the equalization of flows and organic shock load shall be considered at all plants which are critically affected by surge loadings.ii. Organic Design. Organic loadings for wastewater treatment plant design shall be based on the information provided in the preliminary engineering report required by Section 411. The effects of septage flow which may be accepted at the plant shall be given consideration and appropriate facilities shall be included in the design. See Section 520.iii. Shock Effects. The shock effects of high concentrations and diurnal peaks for short periods of time on the treatment process, particularly for small treatment plants, shall be considered.e. Conduits. All piping and channels shall be designed to carry the maximum expected flows. Conduits shall be designed to avoid creation of pockets and corners where solids can accumulate.f. Gates or Valves. Suitable gates or valves shall be placed in channels to seal off unused sections which might accumulate solids. The use of shear gates, stop plates or stop planks is permitted where they can be used in place of gate valves or sluice gates. Non-corrodible materials shall be used for control gates and conduits.g. Arrangement of Units. Component parts of the plant shall be arranged for appropriate operating and maintenance convenience, flexibility, economy, continuity of maximum effluent quality, and ease of installation of future units.h. Flow Division Control. Flow division control facilities shall be provided as necessary to ensure organic and hydraulic loading control to plant process units and shall be designed for easy operator access, change, observation, and maintenance. Appropriate flow measurement facilities shall be incorporated in the flow division control design.i. Odor Management. An odor management plan shall be submitted to and approved by the Department as a part of the preliminary engineering report described in Section 411. The Water Environment Federation Guidance referenced in Section 008 of these rules provides guidance for use in developing an odor management plan that is inclusive of the facilities being designed.j. Cold Weather. Facilities shall be designed with regard for proper operation and maintenance and protection during cold weather temperatures expected at the specific location. The Water Environment Federation Guidance referenced in Section 008 of these rules provides guidance for use in designing, operating and maintaining facilities in cold weather.04.Plant Details.a. Unit Bypasses. i. Removal from Service. Properly located and arranged bypass structures and piping shall be provided so that each unit of the plant can be removed from service independently. The bypass design shall facilitate plant operation during unit maintenance and emergency repair so as to minimize deterioration of effluent quality and ensure rapid process recovery upon return to normal operational mode. The actuation of all bypasses shall require manual action by operating personnel. All power-actuated bypasses shall be designed to permit manual operation in the event of power failure.ii. Unit Bypass During Construction. Unit bypassing during construction shall be in accordance with the preliminary engineering report required by Section 411.b. Unit dewatering, flotation protection, and plugging. Drains or sumps shall be provided to completely dewater each unit to an appropriate point in the process. Due consideration shall be given to the possible need for hydrostatic pressure relief devices to prevent flotation of structures. Pipes subject to plugging shall be provided with means for mechanical cleaning or flushing.c. 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.d. Painting. The contents and direction of flow shall be identified on the piping in a contrasting color.e. Operating equipment. Tools, accessories, and spare parts necessary for the plant operator's use shall be provided.f. Storage and work space facilities. Readily accessible storage and work space facilities shall be provided, and consideration shall be given to provision of a garage for large equipment storage, maintenance, and repair.g. Erosion control during construction. Effective site erosion control shall be provided during construction.h. Grading and landscaping. Upon completion of the plant, the ground shall be graded and landscaped in accordance with the preliminary engineering report developed in the preliminary engineering report required by Section 411.05.Plant Outfalls. a. Discharge impact control. The outfall shall be designed to discharge to the receiving stream in a manner acceptable to various reviewing authorities including, but not limited to, EPA, the Idaho Department of Environmental Quality, U.S. Army Corp of Engineers, Idaho Department of Water Resources, and local jurisdictions.b. Protection and Maintenance. The outfall shall be so constructed and protected against the effects of floodwater, ice, or other hazards as to reasonably ensure its structural stability and freedom from stoppage. Hazards to navigation shall be considered in designing outfalls.c. Sampling Provisions. All outfalls shall be designed so that a sample of the effluent can be obtained at a point after the final treatment process and before discharge to or mixing with the receiving waters.06.Essential Facilities. a. Emergency Power Facilities. i. General. All wastewater treatment plants shall be provided with an alternate source of electric power or pumping capability to allow continuity of operation during power failures. Refer to Subsection 440.07.c. for design requirements. Methods of providing alternate sources include:(1) The connection of at least two (2) independent power sources such as substations. A power line from each substation is required if this method is used. The determination of the independent power sources shall be done by the appropriate power provider and stated in a letter from that provider.(2) In-place internal combustion engine equipment which will generate electrical or mechanical energy.(3) Portable pumping equipment when only emergency pumping is required. 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.ii. Power for Aeration. Standby generating capacity normally is not required for aeration equipment used in the activated sludge process. In cases where a history of chronic, long-term (four (4) hours or more) power outages have occurred, auxiliary power for minimum aeration of the activated sludge will be required as provided in Subsections 450.06.a.i.(1) or 450.06.a.i.(2).iii. Power for Disinfection. Standby generating capacity, as provided in Subsections 450.06.a.i.(1) or 450.06.a.i.(2), is required for disinfection facilities and dechlorination facilities.b. Water Supply. Section 009 provides a reference to the Uniform Plumbing Code, compliance with which may be required by other law.c. Sanitary Facilities. Section 009 provides a reference to the Uniform Plumbing Code, compliance with which may be required by other law.d. Stairways. Stairways shall be installed in lieu of ladders for top access to units requiring routine inspection and maintenance (such as digesters, trickling filters, aeration tanks, clarifiers, tertiary filters, etc.).e. Flow Measurement.i. Location. Flow measurement devices shall be provided to measure the following flows: (1) Plant influent or effluent flow.(2) If influent flow is significantly different from effluent flow, both shall be measured or otherwise accounted for by other flow measurement facilities.(3) Other flows required to be monitored under the provisions of the discharge permit.(4) Other flows such as return activated sludge, waste activated sludge, and recycle required for plant operational control.ii. Devices. Indicating, totalizing, and recording flow measurement devices for all influent or effluent flows shall be provided for all plants. Any other flow measurement device may be indicating and totalizing only. All flow measurement equipment must be sized to function to a satisfactory level of accuracy over the full range of flows expected and shall be protected against freezing.iii. Hydraulic Conditions. Flow measurement equipment including approach and discharge conduit configuration and critical control elevations shall be designed to ensure the required hydraulic conditions necessary for the measurement accuracy needed for the specific application.iv. Calibration and Certification. The flow measurement devices specified in Subsections 450.06.e.i.(1) through 450.06.e.i.(3) shall be calibrated and certified at manufacturer-specified frequencies.f. Sampling Equipment. Effluent composite sampling equipment shall be provided at all mechanical plants and at other facilities where necessary to meet discharge permit monitoring requirements. Composite sampling equipment shall also be provided as needed for influent sampling and for monitoring plant operations. The influent sampling point shall be located prior to any process return flows.07.Safety. a. General. 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. Enclosure of the plant site with a fence and signs designed to discourage the entrance of unauthorized persons and animals is required.b. Hazardous Chemical Handling. The materials utilized for storage, piping, valves, pumping, metering, splash guards, etc., shall be specially selected considering the physical and chemical characteristics of each hazardous or corrosive chemical.08.Laboratory. a. All treatment plants shall include a laboratory for making the necessary analytical determinations and operating control tests, except for those plants utilizing only processes not requiring laboratory testing for plant control and where satisfactory off-site laboratory provisions are made to meet the permit monitoring requirements. The laboratory shall have sufficient size, bench space, equipment, and supplies to perform all self-monitoring analytical work required by discharge permits, and to perform the process control tests necessary for good management of each treatment process included in the design.b. Treatment plant laboratory needs may be divided into the following three (3) general categories:i. Plants performing only basic operational testing; this typically includes pH, temperature, dissolved oxygen, and chlorine residual.ii. Plants performing more complex operational and permit laboratory tests including biochemical oxygen demand, suspended solids, and fecal coliform analysis.iii. Plants performing more complex operational, permit, industrial pretreatment, and multiple plant laboratory testing.c. Expected minimum laboratory needs for the three (3) plant classifications set out in Subsection 450.08.b. must be addressed in the preliminary engineering report.09.Instructions and Equipment. Wastewater treatment 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.10.Operation and Maintenance. 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.Idaho Admin. Code r. 58.01.16.450