Current through August 31, 2023
01.
Plant Location. (3-31-22)
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. (3-31-22)
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. (3-31-22)
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. (3-31-22)
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. (3-31-22)
03.
Design. (3-31-22)
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. (3-31-22)
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: (3-31-22)
i. Monitoring observations, including test
results and engineering evaluations, demonstrating the efficiency of such
processes. (3-31-22)
ii. Detailed
description of the test methods. (3-31-22)
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.
(3-31-22)
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.
(3-31-22)
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. (3-31-22)
d. Design Loads. (3-31-22)
i. Hydraulic Design. (3-31-22)
(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.
(3-31-22)
(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. (3-31-22)
(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. (3-31-22)
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. (3-31-22)
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.
(3-31-22)
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. (3-31-22)
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. (3-31-22)
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. (3-31-22)
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. (3-31-22)
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. (3-31-22)
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. (3-31-22)
04.
Plant Details. (3-31-22)
a. Unit
Bypasses. (3-31-22)
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. (3-31-22)
ii. Unit Bypass During Construction. Unit
bypassing during construction shall be in accordance with the preliminary
engineering report required by Section
411. (3-31-22)
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. (3-31-22)
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. (3-31-22)
d.
Painting. The contents and direction of flow shall be identified on the piping
in a contrasting color. (3-31-22)
e. Operating equipment. Tools, accessories,
and spare parts necessary for the plant operator's use shall be provided.
(3-31-22)
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. (3-31-22)
g. Erosion control during construction.
Effective site erosion control shall be provided during construction.
(3-31-22)
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. (3-31-22)
05.
Plant Outfalls. (3-31-22)
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. (3-31-22)
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.
(3-31-22)
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. (3-31-22)
06.
Essential Facilities.
(3-31-22)
a. Emergency Power Facilities.
(3-31-22)
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: (3-31-22)
(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. (3-31-22)
(2) In-place internal combustion engine
equipment which will generate electrical or mechanical energy.
(3-31-22)
(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.
(3-31-22)
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). (3-31-22)
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. (3-31-22)
b.
Water Supply. Section
009 provides a reference to the
Uniform Plumbing Code, compliance with which may be required by other law.
(3-31-22)
c. Sanitary Facilities.
Section 009 provides
a reference to the Uniform Plumbing Code, compliance with which may be required
by other law. (3-31-22)
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.).
(3-31-22)
e. Flow Measurement.
(3-31-22)
i. Location. Flow measurement
devices shall be provided to measure the following flows: (3-31-22)
(1) Plant influent or effluent flow.
(3-31-22)
(2) If influent flow is
significantly different from effluent flow, both shall be measured or otherwise
accounted for by other flow measurement facilities. (3-31-22)
(3) Other flows required to be monitored
under the provisions of the discharge permit. (3-31-22)
(4) Other flows such as return activated
sludge, waste activated sludge, and recycle required for plant operational
control. (3-31-22)
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.
(3-31-22)
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. (3-31-22)
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. (3-31-22)
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.
(3-31-22)
07.
Safety. (3-31-22)
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. (3-31-22)
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.
(3-31-22)
08.
Laboratory. (3-31-22)
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.
(3-31-22)
b. Treatment plant
laboratory needs may be divided into the following three (3) general
categories: (3-31-22)
i. Plants performing
only basic operational testing; this typically includes pH, temperature,
dissolved oxygen, and chlorine residual. (3-31-22)
ii. Plants performing more complex
operational and permit laboratory tests including biochemical oxygen demand,
suspended solids, and fecal coliform analysis. (3-31-22)
iii. Plants performing more complex
operational, permit, industrial pretreatment, and multiple plant laboratory
testing. (3-31-22)
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. (3-31-22)
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. (3-31-22)
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. (3-31-22)