01.
Scope. Section
455 includes additional
requirements for approval of private municipal wastewater treatment plants.
Individual extended treatment package systems for on-site systems are not
covered by these rules, but are covered by IDAPA 58.01.03,
"Individual/Subsurface Sewage Disposal Rules." See Technical Guidance Manual
for Individual and Subsurface Sewage Disposal Systems at
http://www.deq.idaho.gov/.
Private municipal wastewater treatment plants may be considered if no other
viable alternative is available. (3-31-22)
02.
Preliminary Engineering
Report. A preliminary engineering report as described in Section
411 must be submitted to the
Department for review and must be approved by the Department prior to submittal
of plans and specifications. The preliminary engineering report for private
municipal wastewater treatment plants shall include the information listed in
Subsections 455.02.a. and 455.02.b., as
well as information specified in Section
411. (3-31-22)
a. The preliminary engineering report shall
evaluate the following alternatives: (3-31-22)
i. Wastewater treatment plants (possibly
several technologies). (3-31-22)
ii. Self-contained lagoon.
(3-31-22)
iii. Conventional septic
tank and drainfield (or alternate drainfield design). (3-31-22)
iv. Surface water discharge including impact
on TMDLs. (3-31-22)
v. Gravity or
pressure sewer into nearby community (see Subsection
455.04.e. for distances to
community systems and required hook-up.) (3-31-22)
vi. Recirculating or intermittent sand
filter. (3-31-22)
vii. Annual
operation and maintenance costs. (3-31-22)
viii. Land application/reuse.
(3-31-22)
b. The
preliminary engineering report must thoroughly analyze the effect of the
treatment plant discharge on ground water quality, especially bacteria,
viruses, phosphorus and nitrates as compared to the alternatives listed in
Subsection 455.02.a.
(3-31-22)
03.
Plan
and Specification Approval. (3-31-22)
a. Plans and specifications for the
collection and treatment systems will not be approved until the owner is in
receipt of one of the following (whichever is applicable): (3-31-22)
i. A draft NPDES permit from EPA for proposed
surface water discharges; or (3-31-22)
ii. A draft wastewater land application/reuse
permit from the Department for proposed land application or reuse of the
effluent. See the Guidance for Reclamation and Reuse of Municipal and
Industrial Wastewater at
http://www.deq.idaho.gov.
(3-31-22)
b. For a
subsurface treatment and dispersal system (SSDS): (3-31-22)
i. The plans and specifications for the
dispersal system must receive approval from the Department prior to receipt of
the SSDS permit from the district health department having jurisdiction; and
(3-31-22)
ii. The plans and
specifications for the collection system will not be approved by the Department
until the owner is in receipt of the SSDS permit from the district health
department having jurisdiction. (3-31-22)
c. For private municipal wastewater treatment
plants storing their treated effluent prior to irrigation or surface water
discharge, the following additional items shall be considered by the
Department, prior to approving either the treatment systems or the disposal
option. These include, but are not limited to, sealing of storage ponds,
filtration and disinfection requirements prior to use or discharge, the degree
of treatment, and the intended type and area of irrigation. See IDAPA 58.01.17,
"Recycled Water Rules." (3-31-22)
04.
Private Municipal Wastewater
Treatment Plants. (3-31-22)
a. The
private municipal wastewater treatment plant shall have at least two (2) full
years of operating data on five (5) separate installations in the United
States. The data submittal shall include the name, address, and telephone
number for a regulatory agency contact person familiar with the performance of
each reported installation. (3-31-22)
b. The owner shall provide for a wastewater
system operator in responsible charge of the facility. The operator license
classification requirement will depend on the classification of the system
based on Section 202 and the
licensure requirements of Section
203. If the operator is provided by
contract, the contract shall be submitted to the Department for review and
approval. (3-31-22)
c. A sludge
management plan must be submitted to and approved by the Department. The plan
must include collection, treatment and disposal of the sludge. Additionally, a
signed contract that provides for ultimate legal disposal of the sludge shall
be submitted to the Department prior to plan and specification approval.
(3-31-22)
d. The private municipal
wastewater treatment plant shall be a dual train type (or equivalent/greater)
with redundant pumps and blowers from influent works to the disposal site and
provide sufficient redundancy to continue processing incoming wastewater at
peak flows while any one (1) component or process is out of service. Standby or
emergency power shall be provided to fully operate the wastewater treatment
plant during a power outage unless the water system would also be out during a
power outage. (3-31-22)
e. A
compliance agreement schedule authorized by Section
39-116A, Idaho Code, shall be
required for each private municipal wastewater treatment plant approved unless
specifically waived by the Department in writing. If a private municipal
wastewater treatment plant installation is only a temporary or interim measure
in a long-term plan, a compliance agreement schedule will include a sunset
clause with a date for the private municipal wastewater treatment plant to
cease operation and will require the plant owner to fund and construct the
eventual hookup to the public municipal wastewater collection system when the
system becomes reasonably accessible. The compliance agreement schedule shall
address such things as operation and maintenance requirements and monitoring,
reporting requirements, and other project-specific items as applicable. The
owner shall be responsible for complying with the requirements of the
compliance agreement schedule. The compliance agreement schedule must be
renewed every five (5) years; when ownership of the treatment plant changes; or
at the request of the owner(s) or Department, so long as the system is in
operation. (3-31-22)
f. If the
Department determines that a proposed private municipal wastewater treatment
plant is reasonably accessible to a public municipal wastewater collection
system, the use of the private municipal wastewater treatment plant may be
denied. (3-31-22)
g. Minimum Size.
The minimum size of a private municipal wastewater treatment plant allowed
under these rules is twenty-five thousand (25,000) gallons per day design
capacity based on average day flows. (3-31-22)
i. The minimum size requirements do not apply
to proposed systems with suitably configured passive wastewater treatment
technologies including, but not limited to, facultative lagoons, free water
surface wetlands, and vegetated submerged beds. (3-31-22)
ii. The Department may approve private
municipal wastewater treatment plants smaller than twenty-five thousand
(25,000) gallons per day design capacity, based on average day flows, provided
the treatment plant will be maintained under original ownership.
(3-31-22)
iii. For the Department
to approve the transfer of ownership of a private municipal wastewater
treatment plant smaller than twenty-five thousand (25,000) gallons per day
design capacity, based on average day flows, to another entity, the technical,
financial, and managerial requirements in Section
409 must be demonstrated by the
proposed new owner. (3-31-22)
05.
Private Municipal Wastewater
Treatment Plants with Drainfields. In addition to the applicable
requirements of these rules, the subsurface sewage disposal design,
construction and operation shall comply with IDAPA 58.01.03,
"Individual/Subsurface Sewage Disposal Rules." The exception to this is for
Class A reclaimed wastewater reuse facilities that discharge to the subsurface.
These reuse facilities are regulated by IDAPA 58.01.17, "Recycled Water Rules."
(3-31-22)