Current through Register Vol. 24-06, March 15, 2024
(2) Engineering report contents. All
engineering reports required under this chapter must reflect acceptable
engineering practices and demonstrate the capacity of the generator to protect
public health and the environment. The lead and non-lead agencies will
determine the scope of the engineering report. Reports must include:
(a) Sufficient detail for a professional
engineer to complete plans and specifications without substantial
changes.
(b) Name and contact
information for the owner and the owner's authorized
representative(s).
(c) A project
description and location maps. The maps must include:
(i) Location of all wastewater treatment and
reclaimed water generation facilities, as well as all reclaimed and
inadequately treated water storage facilities under direct control of the
generator.
(ii) All additional
facilities that may be under control of the generator, such as for storage and
distribution of reclaimed water.
(iii) All potable water supply sources,
wellhead protection areas for municipal water sources, and system facilities
within one thousand feet of all identified potential reclaimed water
generation, reclaimed water storage, and inadequately treated water storage
facility areas, and any proposed use areas.
(d) Proposed quantity and quality of the
reclaimed water generated by the reclaimed water facility, including an
assessment that the proposed water quality meets the requirements for all
proposed beneficial uses included in Table 3 of WAC 173-219-390.
(e) Description of who will operate and
maintain the reclaimed water facility.
(f) Documentation of contact with potable
water systems and their concerns, if any, as required in WAC
173-219-180(1)(c).
(g) Applicable
requirements of chapter 51-56 WAC, including pipe colors and
labeling.
(h) Design information
for the reclaimed water distribution system directly under the control of the
generator to demonstrate compliance with the requirements of WAC 173-219-360,
and if applicable, consistent with pressurized distribution systems in the most
recent edition of health's Water System Design
Manual.
(i) The
anticipated amount, characteristics, and strength of the source water to be
treated, including BOD5, DO, TSS, and nitrate levels,
and the degree of treatment required to generate proposed reclaimed water
quality, and other influencing factors.
(j) Descriptions of proposed treatment
processes, including preliminary flow diagrams of critical reclaimed water unit
processes, as well as anticipated reliability features and controls. The report
must contain sufficient detail to verify that the proposed facility will comply
with the water quality and reliability requirements of this chapter.
(k) Description of alternative design options
considered.
(l) Hydraulic, organic,
and influent loading rates to the reclaimed water treatment facility.
(m) Summary of preliminary engineering design
criteria for reclaimed water treatment processes, if required, including:
(i) Aeration/anaerobic organic carbon
reduction.
(ii) Nutrient reduction,
if required.
(iii) Disinfection
system selection meeting the requirements of WAC 173-219-340.
(iv) Contact time within the disinfectant
reactor.
(v) Coagulation and
filtration processes, if required.
(vi) Reverse osmosis or comparable technology
process, if required.
(n) A description of compliance with
treatment reliability standards in WAC 173-219-350.
(o) A statement regarding or demonstration of
compliance with:
(i) State Environmental
Protection Act (SEPA), State Environmental Review Process (SERP), or National
Environmental Protection Act (NEPA).
(ii) Any applicable state or local water
quality management plan or any plan adopted under the Federal Water Pollution
Control Act as amended.
(iii)
RCW
90.46.130, including any compensation or
mitigation plans.
(iv) Governor's
Executive Order 05-05 Archaeological and Cultural Resources.
(p) A pilot study proposal, if
required. The lead agency may require a pilot reclaimed water facility study to
evaluate the ability of the proposed facility to meet all reclaimed water
quality requirements applicable to the project. The generator must include
discussion and determination of the need for a pilot study in the engineering
report and include the proposal for it, if required.
(q) Proposed pipeline separation distances,
both horizontal and vertical, consistent with the most recent edition of
ecology's and health's Pipeline Separation Design and Installation
Reference Guide, in order to ensure trench stability and adequate
access for repair and replacement, to minimize impacts to nearby utility pipes,
and to protect public health.
(r)
Wetlands. If a proposed beneficial use of the reclaimed water is
for a wetland, or wetland restoration and/or enhancement, the reclaimed water
engineering report must include the following:
(i) The wetland-rating category, size,
hydrogeomorphic class, and vegetation class of the existing and proposed
wetlands.
(ii) The beneficial uses
of the existing and proposed wetland.
(iii) The hydrologic regime of the existing
and proposed wetland, including depth and duration of inundation, average
monthly water level fluctuations, and annual loadings of reclaimed water to the
wetlands.
(iv) Demonstration that
the proposed quality of reclaimed water meets the requirements for this
beneficial use.
(v) Any studies
conducted or additional information applicable to the specific project or
site.
(vi) Information to support a
claim of net environmental benefit, if proposed. At a minimum, a claim of net
environmental benefit must demonstrate that the use of reclaimed water:
(A) Provides full and uninterrupted
protection of all significant beneficial uses existing in the wetland prior to
the use of reclaimed water.
(B)
Creates new, or enhances existing, beneficial uses of the wetland.
(s)
Surface water
augmentation. If a proposed beneficial use of the reclaimed water is for
surface water augmentation, the engineering report must also include the
following:
(i) The location and proposed
augmentation uses of the reclaimed water.
(ii) Demonstration of how the reclaimed water
meets water quality standards at the point of release.
(iii) If applicable, identify potable water
supply intakes that are within one thousand feet of the reclaimed water use
area, and discuss whether a two hundred foot minimum separation distance
between them is sufficient to protect the potable water supply intake(s) from
physical impairment potentially created from a reclaimed water use for surface
water augmentation. Include demonstration that reclaimed water quality and
quantity will not cause need for intake modifications or additional treatment
requirements for the production of potable water.
(t)
Groundwater/aquifer
recharge. If a proposed beneficial use of the reclaimed water is for
aquifer recharge, the engineering report must also include the following:
(i) Information requested by the lead agency
necessary to assess the specific treatment and use of reclaimed water for
application to recharge groundwater.
(ii) Site-specific information presented in
the following:
(A) Project operation
plan.
(B) Conceptual model of the
hydrogeologic system.
(C)
Description of the legal framework.
(D) Environmental assessment and analysis of
any potential adverse conditions or potential impacts to the surrounding
ecosystem.
(E) Project mitigation
plan, if required by the lead agency.
(F) Project monitoring plan.
(G) Pilot demonstration of project
performance.
(u)
Recovery of reclaimed water stored
in an aquifer. Aquifer recharge and recovery projects will be evaluated
based on the information provided in the engineering report under (t) of this
subsection using the following criteria:
(i)
Aquifer vulnerability and hydraulic continuity.
(ii) Aquifer boundaries and
characteristics.
(iii) Geotechnical
impacts of project operation.
(iv)
Chemical compatibility of surface waters and groundwater.
(v) Recharge and recovery treatment
procedures.
(vi) System
operation.
(vii) Potential
impairment of existing water rights.
(viii) Environmental impacts.
(ix) Pilot demonstration project
performance.
(v)
On-site sewage treatment. If the generator is or will be operating
an on-site sewage treatment system, the generator may reference an approved
engineering report, but the reclaimed water engineering report must also
include the on-site sewage treatment system predesign report, site and
environmental review, and engineering report as required under chapter 246-272B
WAC, Parts 3 and 4.
(w)
Conveyance in waters of state. For projects proposing conveyance
in waters of the state, the engineering report must include the technical basis
for the proposal.