Washington Administrative Code › Title 173 - Ecology, Department of (See also Titles 197, 317, 372, and 508) › Chapter 173-219 - RECLAIMED WATER › Section 173-219-210 - Engineering report

Current through Register Vol. 24-14, July 15, 2024
(1) Submission
			 of engineering report to lead agency. The engineering report is the technical
			 basis for the design of a proposed reclaimed water facility. A generator must
			 comply with the requirements of WAC 173-219-180(1)(b) and (c)    and include a
			 section or stand-alone engineering report meeting the requirements of WAC
			 173-240-060 for the wastewater
			 treatment facility or chapter 246-272B WAC, Part 4, for the on-site sewage
			 systems, that will provide source water for the proposed reclaimed water
			 facility. This does not apply if the source water is raw sewage.
(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.